Service Ready Architecture for Schools Design Guide

Service Ready Architecture for Schools Design Guide
Cisco Service Ready Architecture for Schools Design Guide
Last Updated: July 9, 2010
Building Architectures to Solve Business Problems
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Cisco Service Ready Architecture for Schools Design Guide
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About Cisco Validated Design (CVD) Program
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About the Authors
Solution Authors
Martin Pueblas, CCIE#2133, CISSP#40844—Technical Leader, CMO Enterprise
Solutions Engineering (ESE), Cisco Systems
Martin Pueblas
Martin is the lead system architect of the Cisco SAFE Security Reference Architecture. He is a network security expert with
over 17 years of experience in the networking industry. He obtained his CCIE certification in 1996 and CISSP in 2004. Martin joined Cisco in 1998 and has held a variety of technical positions. Started as a Customer Support Engineer in Cisco’s
Technical Assistance Center (TAC) in Brussels, Belgium. In 1999 moved to the United States where soon became technical
leader for the Security Team. Martin’s primary job responsibilities included acting as a primary escalation resource for the
team and delivering training for the support organization. At the end of 2000, he joined the Advanced Engineering Services
team as a Network Design Consultant, where he provided design and security consulting services to large corporations
and Service Providers. During this period, Martin has written a variety of technical documents including design guides and
white papers that define Cisco’s best practices for security and VPNs. Martin joined Cisco’s Central Marketing Organization in late 2001, where as a Technical Marketing Engineer, he focused on security and VPN technologies. In late 2004, he
joined his current position acting as a security technical leader. As part of his current responsibilities, Martin is leading the
development of security solutions for enterprises.
Brian Cox,CCIE#4836, CWN#73—Technical Leader, CMO Enterprise Solutions Engineering (ESE), Cisco Systems
Brian Cox
Brian is a Technical Leader at Cisco, with a primary focus on WLANs and mobility. His current role is network design of service ready architectures providing core services such as security, mobility and unified communications over resilient networks. Brian has authored many technical papers, including multiple Mobility Design Guides, Secure Mobility Design
Guides, and a Voice over WLAN Design Guide. He holds a master of engineering degree with a specialization in communications from the Royal Melbourne Institute of Technology
Srinivas Tenneti, CCIE#10483—Technical Marketing Engineer, CMO Enterprise Solutions Engineering (ESE), Cisco Systems
Srinivas is a Technical Marketing Engineer for WAN and branch architectures in Cisco's ESE team. Prior to joining the ESE
team, Srinivas worked two years in Commercial System Engineering team where he worked on producing design guides,
and SE presentations for channel partners and SEs. Before that, he worked for 5 years with other Cisco engineering teams.
Srinivas has been at Cisco for 8 years.
Srinivas Tenneti
Steve Gyurindak, CCIE#9057, CISSP#61046—Solutions Architect, Enterprise Solutions Engineering (ESE), Cisco Systems
Steve is a solutions architect with over 15 years of industry experience. He joined Cisco in 2000 and worked the first 8 and
a half years as a Systems Engineer covering the Service Provider, North Florida/Alabama Commercial, Georgia Enterprise
and US Channels sales markets. Steve has been recognized for his work with some of Cisco's most influential customers
as well as for his work in South America and Europe. Steve joined ESE in 2009 to lead the development of customerfocused architectures and designs for the Education Market. Steve has a Bachelor of Science degree in Telecommunications from the State University of New York at Buffalo, and is currently pursuing a Master's of Science degree in Network
Telecommunications at New York University. In addition to a CCIE in Routing and Switching, Steve holds the following certifications: CISSP, CCNP, CCDP, CCNA, CCDA, MCSE, and MCNE.
Steve Gyurindak
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About the Authors
Solution Authors
John Strika, Technical Marketing Engineer, CMO Enterprise Solutions Engineering
(ESE), Cisco Systems
John Strika
John is a Technical Marketing Engineer in Cisco's Public Sector ESE team, with expertise in the areas of mobility and
location-based services. He has coauthored documents on enterprise mobility and Wi-Fi location-based services. As
a member of Cisco's Enterprise Architecture Board, he helps maintain Cisco's vision and architectural direction and
define Cisco's roadmap for context-aware and presence solutions. Previously, John was Cisco's first mobility consulting systems engineer, responsible for architecting creative wireless solutions for large enterprise customers. His 28
years of experience spans network design and implementation, applications development, facilities planning and
management, consulting, and general management. His past roles have included mission-critical telecommunications
design and development at AT&T and systems programming and data communications management with Wall Street
brokerages and commercial banks. Prior to joining Cisco, Strika was at Telxon Corporation (parent of Cisco's Aironet
wireless acquisition) for nine years, reaching the position of Southern Division Vice President of Wireless Technologies and Services. He is a member of the IEEE and has held several Federal Communications Commission licenses in
the use and modification of amateur and commercial radio. His educational background is in electrical engineering
and computer applications programming from Columbia University and in finance from Fordham University's College
of Business Administration, and he holds a masters of communications technology certificate from the American Institute. He was a charter Novell Certified Netware Engineer in the greater New York City area. Always seeking opportunities to use his mobility and advanced communications knowledge to improve public safety as well as the safety of our
public servants, John has served in volunteer search and rescue as well as a Reserve Deputy.
Bruce McMurdo, CCIE# 1537—Technical Leader, CMO Enterprise Solutions Engineering (ESE), Cisco Systems
Bruce McMurdo
Bruce has more than 20 years of experience in data networking. He has been employed at Cisco since 1996, working
as a network consulting engineer, a wireless LAN product manager, and most recently as a technical leader. Bruce has
technical expertise in network virtualization, wireless LANs, and unified communications, and has frequently presented and published on these subjects.
Rahul Kachalia, CCIE#11740—Technical Marketing Engineer, CMO Enterprise
Solutions Engineering (ESE), Cisco Systems
Rahul is a technical marketing engineer in Cisco's Enterprise Solution Engineering group, helping to create the design guidance that will help build the 21st century school network infrastructure. Rahul has
more than 14 years of broad engineering experience, primarily in service provider core and edge
focused products and technologies including broadband, MPLS, VPN and managed services. He has
led many assurance projects to develop solutions that can deliver design guidance and accelerate
Rahul Kachalia
deployments from traditional WAN infrastructure to next-generation IP/MPLS managed core networks. In
the Enterprise Solution Engineering group he has also worked on designing next-generation unified virtual campus networks for large enterprise customers. In addition to CCIE, Rahul holds CCNP, CCNA,
MCSE, MCP, and CNE. He holds a bachelor's degree from Mumbai University, India.
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C O N T E N T S
CHAPTER
CHAPTER
1
2
Executive Summary 1-1
Introduction 1-1
Design Guide Structure 1-2
Supplement Documents 1-2
Today’s Education Environment
1-2
Architectural Design Considerations
2-1
Overall Design
2-2
Service Ready Architecture for Schools—Foundational Technologies
High Availability 2-4
Redundancy 2-5
Quality-of-Service (QoS) 2-7
QoS Deployment Guidelines 2-8
Service Ready Architecture for Schools—Key Services
Unified Communications 2-9
Digital Media Systems 2-11
Mobility 2-12
Security 2-13
Conclusion
CHAPTER
3
2-4
2-9
2-14
Building Unified Schools Network Infrastructure 3-1
Hierarchical Network Design 3-2
Collapsed Core Network Design 3-4
District Office Network Design 3-5
Resilient Distributed System 3-8
District Office Access-Layer Edge Services 3-9
Access-Layer Network Control Services 3-11
Resilient Access-Layer Network and System 3-12
District Office Data Center Network Design 3-12
School Site Network Design 3-13
School Collapsed Core Network Design 3-13
School Access-Layer Design 3-15
Deploying Schools Foundation Services
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Implementing EtherChannel in School Network 3-15
EtherChannel Load Balancing 3-18
Deploying Core Network Layer 3-20
Routing Protocol 3-20
Routing Protocol Selection Criteria 3-20
Designing End-to-End EIGRP Routing Domain 3-21
Deploying Multi-Layer Network 3-26
Spanning-Tree in Multilayer Network 3-26
Logical Multi-Layer Network 3-28
Flat Logical Network Design 3-28
Segmented Logical Network Design 3-29
Implementing Layer 2 Trunk 3-31
Unidirectional Link Detection 3-32
Deploying Routed-Access Network 3-33
Implementing EIGRP Routing in Access-Distribution Block
Building EIGRP Network Boundary 3-36
EIGRP Adjacency Protection 3-40
Tuning EIGRP Protocol Timers 3-41
Deploying Multicast in School Network 3-41
Multicast Routing Design 3-43
Deploying PIM-SM 3-44
Implementing IGMP 3-48
Multicast Security—Preventing Rogue Source 3-48
Multicast Security—Preventing Rogue RP 3-49
Deploying QoS in School Network 3-50
QoS in Catalyst Fixed Configuration Switches 3-50
QoS in Cisco Modular Switches 3-51
QoS Framework 3-52
QoS Trust Boundary 3-54
Deploying QoS 3-54
Implementing QoS Trust Mode 3-55
Implementing QoS Classification 3-56
Implementing Ingress Policer 3-59
Implementing Ingress Marking 3-60
Applying Ingress Policies 3-61
Applying Ingress Queueing 3-62
Deploying Egress QoS 3-64
Deploying Network Core QoS 3-68
Deploying District Office or Large School Site Ingress QoS
Deploying Small School Site Ingress QoS 3-69
3-35
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Deploying District Office Egress QoS 3-71
Deploying Large School Site Egress QoS 3-73
Deploying Small School Site Egress QoS 3-75
Building a Resilient Network 3-76
Redundant Hardware Components 3-78
Redundant Power System 3-79
Redundant Network Connectivity 3-79
Redundant Control-Plane 3-79
Operational Resiliency Strategy 3-81
Deploying High Availability in School Network
Network Resiliency 3-82
Implementing IP Event Dampening 3-82
Device Resiliency 3-83
3-82
WAN Design 3-91
WAN Technologies 3-91
Types of Metro Ethernet Services 3-91
Service Deployed in the Design 3-92
Bandwidth Capacity 3-93
Planning 3-93
Implementation 3-95
IP Address Aggregation 3-96
Routing for WAN Connections 3-96
WAN QoS Design 3-97
WAN QoS Policy at District Office 3-97
WAN QoS Policy at School Site 3-99
CHAPTER
4
Introduction
4-1
Network Foundation Protection
4-3
Internet Perimeter Protection 4-4
Internet Border Router Guidelines
Internet Firewall Guidelines 4-6
E-mail Security Guidelines 4-7
Web Security Guidelines 4-12
Network Access Security and Control
Endpoint Protection
4-6
4-17
4-18
Internet Perimeter Security 4-19
Internet Border Router 4-19
Internet Firewall 4-20
Firewall Hardening and Monitoring
4-22
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Network Address Translation (NAT)
Firewall Access Policies 4-24
Firewall Redundancy 4-25
Routing 4-27
4-24
Web Security 4-29
Initial System Setup Wizard 4-30
Interface and Network Configuration 4-30
Configuring Network Interfaces 4-31
Adding Routes 4-32
Configuring DNS 4-33
Time Settings 4-33
Working with Upstream Proxies 4-34
WCCP Transparent Web Proxy 4-34
Defining WSA WCCP Service Group 4-34
Enabling WSA Transparent Redirection 4-35
Enabling WCCP Redirection on Cisco ASA 4-36
Enabling WSA HTTPS Scanning 4-37
Working with Upstream Proxies 4-37
Web Access Policies 4-38
Layer-4 Traffic Monitoring 4-39
(L4TM) 4-39
Configuring L4TM Interfaces 4-39
Configuring WSA L4TM Global Settings 4-40
Configuring Traffic Monitoring 4-40
CHAPTER
5
Cisco Unified Wireless Network Architecture
LWAPP Features 5-3
Schools SRA Architecture 5-4
5-1
Management 5-5
Connection to the Schools SRA Network 5-9
RF Groups and Mobility Groups 5-12
Example WLAN Configurations 5-13
Secured Staff WLAN 5-14
Secured VoWLAN 5-15
Web Authenticated Student Access 5-18
AP Deployments Considerations 5-20
AP 1250 5-21
AP 1140 5-21
Coverage and Site Surveys 5-21
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Single Band vs Dual Band APs
WLC Discovery 5-22
WLC Failover Options 5-23
5-21
Appendix A—Devices and Software Used
CHAPTER
6
5-24
Introduction 6-1
What Are Context-Aware Services? 6-1
Why Use Context-Aware Services? 6-2
Is It Here?—Zone or Inventory Management 6-2
Where Is It?—Asset Tracking 6-3
What Is Its Condition?—Condition Tracking 6-3
What Is Its Status?—Status Monitoring 6-4
Where Is It in My Network?—Network Location Services
Cisco Context-Aware Components 6-4
Wired and Wireless Client Devices 6-5
Cisco Unified Network 6-6
Management and Applications 6-7
Context-Aware Component Interaction 6-8
Network Mobility Services Protocol (NMSP) 6-11
6-4
Context-Aware Services in the Schools Service Ready Architecture 6-12
Component Capacities 6-15
Mobility Services Engine 6-15
WLAN Controllers 6-16
Wireless Control System (WCS) 6-17
Context-Aware Engine for Tags (AeroScout) 6-17
Integration with the Schools Service-Ready Architecture 6-18
MSE Connection to the Network 6-18
Clock Synchronization 6-18
Schools SRA Wireless Control System (WCS) Context-Aware Considerations
WLAN Controller and Ethernet Switch Definition and Synchronization 6-36
Wireless Client Context-Aware Considerations 6-37
RFID Asset Tag Context-Aware Considerations 6-41
Rogue Device Context-Aware Considerations 6-47
Context-Aware Considerations for Wired Device Tracking 6-50
Classification and Marking of NMSP Sessions 6-57
NMSP Traffic Flows Originating At The MSE 6-59
NMSP Traffic Generated By WLAN Controllers 6-60
NMSP Traffic Generated By Context-Aware Switches 6-61
Hardware/Software Releases
6-22
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Context-Aware Services—General Best Practice References
CHAPTER
7
Introduction
6-63
7-1
School Service Ready Architecture Dial Plan 7-1
Design Assumptions 7-1
Example Deployment 7-2
Variable-Length On-Net Dial Plans with Flat Addressing
Call Routing 7-4
Localized Call Ingress 7-5
Using the + Sign on E.164 Numbers 7-5
Localized Call Ingress on IP Phones 7-5
Localized Call Ingress on Gateways 7-9
Globalized Call Routing 7-10
Globalized Call Routing to an 8-digit On-net Number
Localized Call Egress 7-12
Localized Call Egress to an IP Phone 7-12
Localized Call Egress to a Gateway 7-13
7-3
7-11
Building Classes of Service for Unified CM with the Line/Device Approach
Survivable Remote Site Telephony (SRST)
SRST CUCM Configuration 7-19
SRST Router Configuration 7-20
7-17
Emergency Notification of 911 Calls with Cisco Emergency Responder
Voice Messaging
Cisco Unified Mobility
7-24
7-25
Cisco Unified Mobile Communicator
8
7-22
7-22
Cisco Unified Personal Communicator 7.0 7-24
Cisco Unified Personal Communicator Features and Benefits
CHAPTER
7-16
Digital Media System Overview
7-26
8-1
Video Surveillance Overview 8-1
Cisco Digital Media System Architecture
DMS Solution for Schools 8-3
8-2
Desktop Video Application Overview 8-5
Desktop Video Components 8-5
Publishing Live and Video On-Demand Content
8-5
Enterprise TV Application Overview 8-6
Enterprise TV Components 8-7
Broadcasting Live TV or Video On-Demand Content
8-7
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Digital Signage Application Overview 8-8
Digital Signage Components 8-9
Video Surveillance System Architecture 8-9
Cisco Video Surveillance Media Server 8-11
Cisco Video Surveillance Operations Manager 8-11
Cisco Video Surveillance IP Cameras 8-12
Deploying Digital Signage in School Campus 8-14
Centralized Management Model 8-14
Distributed Content Storage Model 8-16
SRA Validated Content Distribution Model 8-17
Implementing Network Services for Digital Signage 8-18
Deploying Cisco DMP in the Access Layer Network 8-19
Manual Deployment 8-19
Applying Ingress QoS Policy on DMP and DMM Port 8-22
Applying Egress QoS Policy on DMP and DMM Port 8-23
Auto Smartport Macro Deployment 8-23
Implementing Auto SmartPort Macro 8-25
Tuning Auto SmartPort Macro 8-25
Implementing Cisco Digital Media Player 8-26
Assigning IP Address to Cisco DMP 8-26
Registering Cisco DMP to Cisco DMM Database 8-27
CHAPTER
9
Access Layer Security 9-1
Catalyst Integrated Security Features (CISF) Protected Ports 9-2
CISF Port Configuration 9-2
NAC Protected Ports 9-3
Cisco Clean Access Components 9-4
Out-of-Band Requirements 9-9
NAC Deployment in the Schools SRA 9-9
Configuring the CAS and CAM 9-11
Adding a CAS to the CAM 9-12
Managing the CAS 9-13
Clean Access Roles 9-18
Layer 2 OOB Example 9-18
Availability Considerations 9-20
Basic Clean Access switch Configuration 9-21
Basic Clean Access Out of Band Switch configuration 9-21
802.1X Protected Ports 9-22
What is 802.1X? 9-22
802.1X and EAP 9-23
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How 802.1X Impacts the Network 9-23
Non-802.1X-Enabled Devices 9-23
802.1X in Schools 9-24
Basic 802.1X Switch Configuration 9-24
NAC 802.1X and CISF in Combination 9-25
DMP Ports 9-25
Surveillance Camera Port 9-26
Power-over-Ethernet 9-26
1250 Power-over-Ethernet 9-26
1140 Power-over-Ethernet (PoE) 9-27
IP Phones 9-27
CHAPTER
10
Large School—Modular Switch Design 10-1
Core/Distribution Virtual Interfaces 10-2
Example Port Channel Configuration 10-3
Example 4500 Modular Switch Port Channel Configuration
Example 2960 Port Channel Configuration 10-3
WLC Connection 10-3
NAC CAS Connection 10-4
Core/Distribution NAC CAS Configuration 10-4
SRST Connection Sample Configuration 10-4
WAN Connection 10-5
10-3
Small School—Stacked Switch Design 10-6
Core/Distribution Virtual Interfaces 10-7
Example Port Channel Configuration 10-7
WLC Connection 10-8
Example 3750 Stack Port Channel Configuration 10-8
NAC CAS Connection 10-8
Core/Distribution NAC CAS Configuration 10-9
SRST Connection 10-9
WAN Connection 10-9
CHAPTER
11
Metro Ethernet Connection Configuration
ASA Connection
11-3
Services Block Connection 11-6
Core/Distribution Virtual Interfaces
WLC Connection
11-7
11-9
NAC CAS Connection
SRST Connection
11-2
11-10
11-11
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NTP
11-11
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CH A P T E R
1
Cisco Service Ready Architecture for Schools
Solution Overview
Executive Summary
Cisco is committed to the education environment and understands the varying complexities and business
influences that impact the continual operation of critical educational network services. As the network
becomes more crucial to the operation of the school district—due to the additional essential services that
utilize it—it is important to create an architecture that addresses the growing complexities and criticality
of the network. The Cisco Service Ready Architecture for Schools was developed as a guide to assist
school leadership in planning for the evolution of the school network. It addresses the current network
service requirements, such as safety and security, network availability, and mobility while building a
foundation that is ready for the addition of future network services as they develop.
Introduction
The Cisco Service Ready Architecture for Schools is a network roadmap for school districts to utilize to
enable 21st century education for students and teachers. This design is built by combining an
understanding of the current and future school district network needs with the best technology available,
while considering the technical and financial constraints faced by school districts.
Cisco’s Service Ready Architecture for Schools is a well designed and validated network architecture
that is flexible, adaptive and cost effective to support a wide range of education services. This
architecture provides the ability to deliver all of the services required of an enhanced learning
environment as well as the ability to collaborate with the other schools, district offices and entities
beyond the district.
The Service Ready Architecture for Schools starts with a base network foundation consisting of a district
office where a majority of the critical applications reside. Connected through a WAN transport of
MetroEthernet, two examples of schools sites are provided. School site 1 consists of a smaller design
from those schools with a lower student/teacher ratio. School site 2 is designed for a larger site. Each
site can co-exist in a single school district or can be treated as separate modules. Having guidance for
two separate sites provides flexibility, modularity and scalability as your school district migrates in size.
The district office and each school site contains the critical technologies, or services, required to achieve
the base goals of safety, learning and efficiency. Tested techniques and guidance is provided so that a
network IT staff can ‘set it and forget it.’
The Service Ready Architecture for Schools takes the guesswork out of designing and configuring a
school network. Cisco Certified Internet Engineers (CCIEs) have designed the network foundation,
based on listening to the top concerns from superintendents across the globe, and provided guidance on
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1-1
Chapter 1
Cisco Service Ready Architecture for Schools Solution Overview
Executive Summary
the key network technologies required to enable and solve those top concerns. The Service Ready
Architecture for Schools was placed in a lab and tested using best practice techniques from over 20+
years of network design. The products, features, and configurations have been validated and can be
utilized in your network.
Design Guide Structure
Cisco’s Service Ready Architecture for schools is broken down into modular, interdependent chapters
as shown in Table 1-1. This guide can be read as an extensive network design guide or in chapters to suit
a particular technology needed.
Table 1-1
Cisco Service Ready Architecture for Schools Solution Overview
Chapter 3, “Network Foundation Design”
Chapter 8, “Digital Media and Video
Surveillance Design”
Chapter 4, “Security Design”
Chapter 9, “Access Layer Security Design”
Chapter 5, “Wireless LAN Design”
Chapter 10, “School Site Design”
Chapter 6, “Context-Aware Services Design”
Chapter 11, “District Office Design”
Chapter 7, “Unified Communications Design”
Supplement Documents
•
Schools Configuration Files Guide—Example CLI Configurations from the validated design
•
Schools Netformix DesignXpert Tool—Netformix Desing Expert Template for Schools SRA
The Service Ready Architecture for Schools network design is a comprehensive validated design based
on proven techniques to take the guesswork out of establishing your school network. The techniques and
guidance provided in the chapters can be used to design and to be deployed in your network easily with
enough room for flexibility and growth. Leveraging the practices given in the Service Ready
Architecture can establish critical technologies to enable and solve your top concerns in your school
network: security, learning and efficiency.
Today’s Education Environment
Schools are facing significant challenges that are creating opportunity and driving transformation of
many aspects of the education environment. Technological innovation is not only applied to the learning
process, but optimized for school operations to drive building and energy efficiencies, heighten the
awareness of, and responsiveness to, safety and security concerns, and improve communications on and
off campus.
Technology can provide a powerful platform for the educational needs of the 21st century.
Cisco delivers the best architectural framework—based on years of experience and cutting edge
technology—to meet the requirements of the education environment. In forming an architectural
framework for education, three key drivers are at the forefront of learning innovation:
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Cisco Service Ready Architecture for Schools Solution Overview
Executive Summary
•
Student performance and assessment remains top of mind. Schools are being held accountable for
the success and failure of their students, and their teachers while demands to provide equitable
opportunities to all learners drives the need for a pervasive technology platform for access to the
experts and resources needed. Governmental influence and accountability continues to drive schools
to demonstrate that their students are successfully advancing
•
Student expectations are changing and engaging kids is increasingly done best with technology.
Social networking, online digital content, customized curriculum, and accessing resources
worldwide are required. Schools are transforming into learning centers that support the development
of basic skills while developing students that are globally aware, internationally competitive and
masterful of 21 st century skills and talent.
•
Teacher Talent and Staff Development focused on leveraging our best expertise and providing
optimal opportunities for students is also best supported with a flexible Communications and
Collaboration platform. Developing teachers while enriching their own work environment with
technology will lead to the innovative application of collaborative tools to students and their
classrooms.
•
With school budgets and funding sources tightly monitored, schools strive to improve operational
efficiencies. When schools streamline operations and processes, they become more cost effective
and create sustainable, on-going savings. Schools increasingly look to the network to support
critical operational functionality such as Energy Monitoring and Management, Emergency Paging
and Communications and Video Based Surveillance and Video Communications. Smart facilities
management creates a school that is not only safer for students, a top issue for schools but also
creates cost efficiencies and sustainable funding for many advanced technologies for the classroom.
•
The ultimate end result of implementing the proper educational framework is to truly transform the
current educational environment to one that promotes learning anywhere, anytime, regardless of the
medium. Leveraging technology to eliminate barriers to accessibility is paramount to educators and
school staff. Making information easy to access enables students to learn at their own pace and not
be constrained to a single method of information delivery. Mechanisms that increase student
performance can be realized through technology to assist in the development of 21st century skills.
Some of the key initiatives to consider are:
•
Smart and flexible learning environments—Classrooms are transforming into dynamic classrooms,
which include digital content, on-line assessment, and pervasive access to rich media. Students are
increasingly becoming the producers of content and controlling more of their own learning and the
physical format of the classroom must change on-the-fly to facilitate the use of advanced
technologies. Classroom walls are being “virtually” eliminated by the power of the network to allow
for access to resources well beyond the physical school building, to be connected to national and
global experts and resources.
•
Technology-enabled learning—Information is being delivered in multiple formats, often combining
methods of delivery to optimize the learning experience. Students are increasingly becoming the
producers of content and a less formal, user-created content library is coming to the forefront in the
education community. Students learn and share via video, photo-sharing, blogs, wikis, instant
messaging, etc. Additionally, as the learning paradigm is shifting the role of the teacher is changing
dramatically and students are developing a much sharper sense of self and audience.
•
Social networking and on-line learning—Students are interfacing with each other and their
educators more than ever. Another interesting trend is that students are publicly publishing their
work more today, which drives a higher expectation for quality in the work they produce. Students
who own their learning, retain their knowledge, and can apply it wherever and whenever it is needed.
•
Convergence of information and communications—Web 2.0 initiatives continue to drive technology
practices in the education community. Unified Communications is becoming more prevalent in
schools and leverages the benefits of an IP-based platform to integrate data-rich information with
communications, facilitating a higher level of responsiveness and engagement with the extended
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Executive Summary
community (the district, other schools, parents, etc.). This drive toward convergence has also
enhanced the safety and security practices in schools where informed emergency response and threat
avoidance are top of mind.
•
Learning communities—Collaborative environments for both students and teachers are on the rise.
Integrating technologies further enhance the experience by providing such utilities as
interactive-video, on-demand video feeds, voice and Web collaboration, video to mobile devices,
and TelePresence. The flexibility of integrating tasks and robust communications accelerates results
for students, teachers, administrators and the community.
•
One-to-one learning—New, inexpensive devices have provided teachers and students with an
environment where everyone has access to a mobile computer, as well as digital content, educational
software, and digital authoring tools.
•
Connected real estate—Converging disparate building networks into a common IP backbone
reduces many costly silos consuming hundreds of thousands of dollars each year. Intelligent and
energy efficient buildings are a high priority for school districts as energy costs have risen and
administrative budgets have been reduced. Connected Real Estate leverages the network to
centralize operations and provide a platform that applies intelligence to basic building functions.
Integrated video and communications are also a key element in promoting the safety and security of
teachers and students. Policing building access or using RFID tagging for the protection of assets is
quickly becoming a popular practice, as is the incorporation of IP video surveillance systems and
emergency response technologies that are integrated to the entire district’s network and the public
safety community.
•
Mobility—One of the largest movements in the education community is the pursuit of anywhere,
anytime, continuous access. More education environments are moving toward wireless networks as
the network of choice. It allows freedom of movement for students and educators and also enhances
safety and security by further augmenting the ability to reach individuals quickly and respond
immediately to emergency situations. Furthermore, the use of laptop computers, Netbooks, and
mobile devices only seems to increase as time goes on. By integrating the preferred learning
technologies with mobile platforms, we can realize flexible learning and an accommodating
environment.
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Service Ready Architecture for Schools—A
Framework for Education
The drivers, key initiatives and requirements of the education environment are evolving beyond the
traditional enterprise network. The next generation network architecture for school environments must
be built on a technical foundation that takes into consideration the current economic environment as well
as other business factors impacting the education market as a whole. The fundamentals of this next
generation network must:
•
Allow many services to operate seamlessly over a common infrastructure.
•
Embed service recognition, awareness, and differentiation into all components.
•
Support different voice, video, and data services while ensuring availability, scalability, and
security.
•
Adapt to network technical innovations that allow for better resiliency and the implementation of
new network services.
•
Integrate these new services and technical innovations with existing network equipment, protocols,
and methods of communication.
The Service Ready Architecture for Schools is a well-designed and validated network architecture that
is flexible, adaptive, and cost effective to support a wide range of educational services. This architecture
provides the ability to deliver all of the services required of an enhanced learning environment, as well
as the ability to collaborate with other schools, district headquarters, and entities beyond the district.
At the heart of the architecture is a robust routing and switching network. Operating on top of this
network are all the services used within the school district, such as safety and security systems, voice
communications, video surveillance, etc. The architecture has been designed around both school
operations and technical considerations.
Architectural Design Considerations
This architecture utilizes key technologies that address the safety and security, connected real estate, and
multi-service requirements of the modern educational network. The architecture is constructed in a
manor that allows these technologies to work seamlessly together.
•
High availability—The high availability technologies used in the Service Ready Architecture for
Schools allow network equipment to eliminate the effects of any unplanned link or network failures
by understanding the typology of the infrastructure and using that information to immediately
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Service Ready Architecture for Schools—A Framework for Education
Overall Design
re-route network traffic without the need to re-learn (reconverge) the network. The use of this
technology allows critical services such as voice and video communications to remain unaffected
by network outages.
•
Single-fabric multi-service—This technology gives the network administrator the ability to have
many different services or networks share the same infrastructure, yet maintain logically separate
networks. As multiple services operate over a single infrastructure, it becomes important to manage
traffic based on the service being utilized. In the education environment this is particularly
important as schools struggle with allowing student access to the same network used for grading
systems, safety and security, and phone conversations.
•
Differentiated services—Certain network services demand more from the network than others. For
example, voice communications do not work if parts of the conversation drop out. Video
conferencing is not useful if the picture keeps freezing. Additionally, a teacher’s use of the network
to enter grades should take precedence over a student surfing the Web. Finally, if there are more
traffic demands than the network can handle, the network should be able decide which traffic is most
important. The ability to understand, mark, shape, and limit traffic is embedded into the Service
Ready Architecture for Schools.
•
Access layer flexibility—Employing a hybrid access layer design allows the network administrator
to leverage an existing Layer 2 network while giving them the flexibility to implement a routed
access layer. Moving the Layer 2/Layer 3 demarcation point to the access switch allows the network
administrator to prevent loops without requiring multiple complex Layer 2 technologies, such as
spanning tree protocol. Additionally, it provides high availability and eases network troubleshooting
and management by leveraging well known Layer-3 troubleshooting tools and technologies.
It is challenging to design architectures for the education environment that include technical innovations
and services needed to support the classroom of the future and also create a safe and secure learning
environment.
Cisco is committed to making this next generation architecture a reality by providing proven, validated
network designs to ease the deployment of these new services. With each design, a deployment model
is adopted and guidance provided on how to deploy services and technical innovations that meet the
business and technical requirements of the education environment.
Overall Design
An architectural model for the school network is shown in Figure 2-1.
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Overall Design
Figure 2-1
Service Ready Architecture for Schools
Large School
Critical Services
for School
Operation
IP
Small School
School Access
L2
Access
Classroom
Classroom
School Access
L3
Access
L2
Access
HDTV
HDTV
IP
Video Surveillance
L3
Access
Critical Services
for School
Operation
IP
IP
Video Surveillance
School
Core
School
Core
Wide Area
Accelerated
Network
WAN Link
PSTN
WAN Link
PSTN
Building
Infrastructures
Mgmt
CRE
Security
DMSc
Network Admission Control
Connected Real Estate
Mobility Location
Network Management
M
Digital Signage Management
Video
Mobility
Phy
Sec
Voice
Call
Proc
M
M
M
M
Unified Message
District Headquarters
(Non-Mission Critical Services Block)
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Unified Communications and
Collaboration
Cisco’s Service Ready Architecture for Schools adopts a mission-critical services model in which
services (safety and security, Unified Communications, and mobility) are deployed and managed at the
district headquarters, allowing each school to reduce the need for separate services to be operated and
maintained by school personnel.
Because many of the services are centrally located within the district office, rather than within each
school itself, high network availability must be maintained. However the architecture also uses resilient
application service features to maintain mission-critical services within the school in the event of a
network failure.
This service model of the architecture allows school districts to maintain a good balance of controlling
costs, pooling technical talent, and managing network services to offer a highly resilient, scalable,
secure, and flexible network for the 21st century school.
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Service Ready Architecture for Schools—Foundational Technologies
Service Ready Architecture for Schools—Foundational
Technologies
The Service Ready Architecture for Schools is the underlying service delivery framework from which
all services and technologies flow for the school and district environments. This foundation must have
simplified configurations and operations to ease the technical expertise required to support the
environment, thus lowering the need for network experts. There is also a need for multiple
core/distribution options to scale to the size, bandwidth, and requirements of the school’s network to
adapt to different size schools and school districts. The technology choices to scale this design and meet
future needs include:
•
High availability—The network must continue operations in the event of a network or service
failure.
•
Redundancy—All critical school services reside within the school to ensure they are not interrupted
in the event of a wide area network outage, but the network should be flexible so as to allow
non-critical services to be located in the district office to leverage economies of scale and lower total
overall cost.
•
Quality of Service (QoS)—The network must ensure proper prioritization of real-time traffic to
enable a media rich network environment supporting voice, video, and data applications.
High Availability
The long-term capability of the network does not require constant hardware or software upgrades. New
features and services can be added via in-service software upgrades. The network is highly available
through redundancy and modularity and capable of providing an increased level of service not currently
realized. Features are upgraded instantly and seamlessly over the network. Cisco can provide nonstop
communications with resiliency and redundancy throughout all the layers of the network.
Many elements must be correctly designed and implemented to achieve such a high standard.
•
Network operations and configuration management:
– Management tools—Simplify provisioning, configuration management, troubleshooting
– Management processes—Consistency of processes, minimize service times, etc.
•
Network design and software features:
– Redundancy—Paths, devices, servers, power, system components, locations, etc.
– Resilience—Ability to function when the network is in a degraded state from an attack,
misconfiguration, maintenance window, etc.
– Prioritization and congestion management of traffic (QoS)
– Security—Harden infrastructure, protect applications and data
•
Hardware and software reliability—Servers, network devices, end-user systems
•
Circuit reliability—WAN and LAN circuits
•
Data center and services edge—Real-time data recovery and data archival capability
For more information, refer to the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/HA_campus_DG/hacampusdg.html.
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Redundancy
•
Path redundancy—End-to-end redundant paths are required (see Figure 2-2) to achieve maximum
redundancy. However at the access layer redundant paths to client end systems are typically
uncommon. Redundant connections are critical in the data center or services edge where the
application servers are located.
Figure 2-2
Second Network Shows End-to-End Redundant Paths
Reliability = 99.938% with Four Hour MTTR (325 Minutes/Year)
Reliability = 99.961% with Four Hour MTTR (204 Minutes/Year)
221673
Reliability = 99.9999% with Four Hour MTTR (30 Seconds/Year)
•
Device redundancy—Redundant devices are usually preferred over redundant components within a
single device. While redundant components within a single device are valuable, the best availability
is usually achieved with completely separate devices (and paths).
•
Power redundancy—Power diversity is another area that must be addressed because redundant
devices attached to a single power source are vulnerable to simultaneous failure. For example,
redundant core switches should have at least two unique power sources. Otherwise, a single power
failure brings down both core switches. Alternatively, backup power could be implemented. These
types of mundane issues are very important when creating a highly-available system.
•
Network design and software features—In a hierarchical network design, the core and distribution
layers can re-converge in less than one second after most types of failures. The access layer typically
has longer convergence times due to the inherent deficiencies of a flat Layer 2 architecture. Bridging
loops, broadcast storms, and slow re-convergence are examples of access layer problems that reduce
end-to-end availability. Spanning Tree typically takes up to one minute to recover from a link or
system outage, which is far too long to support real-time mission critical applications or provide
99.999 percent availability. There are several design changes and software features that can be
implemented to improve availability in the access layer.
•
Access-layer design improvements—Currently, there are three different ways to design the
access-layer control plane. Although all three of them use the same physical layout, they differ in
performance and availability:
– Traditional multi-tier access layer
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This is the traditional design where all access switches run in Layer 2, while distribution switches run
in Layer 2 mode when facing the access layer and in Layer 3 mode when facing the core. Cross-connects
between distribution switches are usually Layer 2 links. When not optimized, this model is dependent
on spanning tree, with all its inherent limitations, to detect and recover from network failures. As
mentioned, load balancing of redundant uplinks is not possible because spanning tree usually blocks one
uplink. HSRP, VRRP, or GLBP must be used to provide First Hop Routing Protocol redundancy.
While noting the deficiencies of the traditional multi-tier approach, design changes and feature
enhancements are available to greatly enhance availability and performance.
The current multi-tier best practice is to create unique VLANs on each access switch as shown in
Figure 2-3.
The best practice design offers several benefits. First, a loop-free topology is created. This means
spanning tree does not impact re-convergence times. Traffic is load balanced across two active uplinks,
achieving maximum throughput and minimum failover times. This loop-free topology also reduces the
risk of broadcast storms and unicast flooding.
Best Practice Multi-Tier Has Unique VLANs on Each Access Switch
Core
Si
VLAN 10
Core
Si
VLAN 20
VLAN 30
Si
VLAN 30
Loop Free Topology
Si
VLAN 30
VLAN 30
Looped Topology
223683
Figure 2-3
One disadvantage of the best-practice multi-tier design is the requirement to redesign the VLAN and IP
addressing scheme—unique IP subnet(s)/VLAN(s) per switch. This can be a significant challenge in
large, mature networks. The routed access model discussed below has this same drawback.
•
Routed access layer
This design improvement, as the name implies, pushes routing into the access layer switches and
creates an end-to-end routed infrastructure. Several important benefits are gained:
– Spanning tree issues are virtually eliminated.
– Re-convergence times for the end-to-end network can be reduced to one second or less.
– Re-convergence times become more predictable with the elimination of spanning-tree.
– Redundant uplinks can be fully utilized.
– HSRP/VRRP is no longer needed to provide host redundancy. This simplifies configuration,
management, and troubleshooting.
– Troubleshooting is accomplished using well-known Layer 3 tools, such as Traceroute, Ping, etc.
– Network layout, naming, and VLAN numbering can be standardized across schools.
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A drawback to the routed access model is the requirement to have separate IP subnets and VLANs
on every access switch. This is in contrast to the traditional multi-tier model where a user VLAN
can span several switches. However the convergence times of the routed access layer are much less
than that of the flat Layer-2 network.
For more information, refer to the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/routed-ex.html.
•
Virtual switch technology
This is a new service enabled by Cisco’s Virtual Switching Systems (VSS) technology on the 6500 series
and stackwise technology on the 3700 series switches. These features allow two or more distribution
switches to be combined into a single virtual switch from a management and data forwarding
perspective. Figure 2-4 highlights this technology.
Core
Physical Network
Cisco’s Virtual Switching Systems
Core
Logical Network
223685
Figure 2-4
VSS provides several compelling benefits over the traditional multi-tier design and the routed access
design:
•
Each access switch with redundant uplinks to two distribution switches now appears to be connected
to a single switch via a two-port Etherchannel.
•
Both links are now forwarding as spanning tree loops have been removed.
•
Link failover times are below one second, consistent with Etherchannel capabilities.
•
HSRP/VRRP are no longer needed to provide default gateway functionality.
•
Unlike the multi-tier or routed access designs, there is no requirement for per-switch VLANs and
IP subnets. This is a significant advantage and means the benefits of VSS technology can be gained
without a major network reconfiguration.
Quality-of-Service (QoS)
There is some debate in the networking industry about the need to deploy QoS in enterprise architectures
because of the ample amounts of bandwidth that make congestion rare. However, during network attacks
or a partial outage, this situation can change dramatically. It has been shown that QoS can serve as a vital
tool to maintain the performance of priority applications and traffic during a degraded network
condition. Reasons why QoS is important in the campus portion of the network include:
•
The introduction of 10Gbps (and higher) link speeds is creating greater mismatches between
high-speed and low-speed links in the campus. This increases the need to buffer and prioritize
traffic.
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•
Well-known applications ports, like HTTP, are being used by a large number of applications. There
is a need to distinguish between high-priority and low-priority traffic using the same port numbers
to ensure priority traffic is transmitted.
•
Prioritized traffic, such as voice and video, must continue to flow even during a network attack or
during a partial failure in the network. Attack traffic often masquerades as legitimate traffic using
well-known port numbers. There is a need to distinguish between legitimate and bogus traffic by
inspecting data packets more deeply.
QoS Deployment Guidelines
The following principles should guide QoS deployments:
•
Classify and mark traffic as close to the network edge as possible. This is called creating a trust
boundary. Traffic crossing the trust boundary is considered trusted and the QoS markings are
adhered to in the rest of the network.
•
Police/rate-limit traffic as close to the source as possible. It is most efficient to drop unwanted traffic
as close to the source as possible, rather than transmitting it further into the network before dropping
it.
•
Perform QoS functions in hardware rather than software. Software-based QoS functions can easily
overwhelm the CPUs of networking devices. High-speed networks require hardware-based QoS
functions.
Figure 2-5 summarizes key QoS functions and where they should be performed.
Figure 2-5
QoS Functions
Endpoints
1
Access
IP
Distribution
Core
Si
Si
Si
Si
WAN
Aggregators
3
223695
2
Trust Boundary
1 Optimal Trust Boundary: Trusted Endpoint
2 Optimal Trust Boundary: Untrusted Endpoint
3 Suboptimal Trust Boundary
For more information, refer to the following:
http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/QoS-SRND-Bo
ok.html
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Service Ready Architecture for Schools—Key Services
Service Ready Architecture for Schools—Key Services
The adoption of IP technology has led to a change in the learning environment. No longer are networks
used solely to provide data communication between computers. IP technology has extended beyond the
data network and is now used extensively for voice and video communication as well. Services that are
a part of the Service Ready Architecture for Schools are shown in Figure 2-6.
Figure 2-6
Services in the Service Ready Architecture for Schools
LocationBased
Services
Access
Control
School
Transportation
Monitoring
Video
Training
Digital
Signage
First Responder
Monitoring
Unified
Communications
IP
Network
Radio
Interoperability
Conferencing
and
Collaboration
PSAP
Integration
Video
Acoustic
Surveillance Building
and
System Motion
Monitoring Sensors
226243
Visitor
Management
Each of these services overlay the IP network and foundational technologies described earlier. While the
services shown in Figure 2-6 are just a sample of the myriad of services available, they can be
summarized into five key services:
•
Unified Communications
•
Digital Media Systems
•
Mobility
•
Security
Unified Communications
Cisco Unified Communications provide many solutions for schools that wish to take advantage of
media-rich unified communications functionality. Each aspect of the total unified communications
architecture provides opportunities for enhancing links within the education community. Functionality
includes IP telephony, unified client software, presence, instant messaging, unified messaging,
rich-media conferencing, mobility solutions, and application development.
•
IP telephony—At the foundation of the Cisco Unified Communications solution is its proven,
industry-leading call processing system, Cisco Unified Communications Manager. This highly
available, enterprise-class system delivers call processing, video, mobility, and presence services to
IP phones, media processing devices, VoIP gateways, mobile devices, and multimedia applications.
The system can scale to one million users across 1000 sites or more or 60,000 users within a single
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clustered system. Built-in redundancy keeps service reliable. Cisco also offers several unified
communications platforms for small districts. All of these standards-based systems work with an
array of third-party phones and dual-mode devices. The systems also provide integration with
existing desktop applications such as calendar solutions, E-mail, enterprise resource planning (ERP)
systems, and customer relationship management (CRM) software. Cisco unified communications
capabilities can also be extended to a variety of mobile phones, including those that run Symbian,
Blackberry, and Windows Mobile operating systems.
•
Unified client software—Cisco offers several rich-media client applications that improve
productivity and simplify processes. Available on Microsoft Windows and Mac OS environments,
as well as mobile operating systems, these clients support a range of applications, including voice,
presence and messaging, unified messaging, video, and conferencing. Communications
functionality has also been unified with applications from industry partners. For example, call
control and presence can be launched and managed from within Microsoft Outlook through a Cisco
Unified Personal Communicator widget or toolbar.
•
Presence and instant messaging—Cisco presence solutions based on Session Initiation Protocol
(SIP) or (SIMPLE) provide SIP presence and proxy services to deliver IM and click-to-call features.
Through the presentation of dynamic presence information, presence solutions allow users to check
the availability of colleagues in real time, reducing phone tag and improving productivity. Cisco
presence and instant messaging solutions work in conjunction with Cisco Unified Communications
Manager and support Cisco Unified Personal Communicator, Cisco IP phones, Cisco IP Phone
Messenger, IBM Sametime clients, and Microsoft clients.
•
Unified messaging—Cisco unified messaging solutions easily integrate with existing environments
and provide flexible deployment options to meet each organization’s individual needs. The broad
range of easy-to-manage solutions includes products tailored for small, medium-sized, and very
large organizations, with feature-rich functionality aligned intelligently with business requirements.
•
Rich-media conferencing—Cisco conferencing solutions help remote workers and teams
communicate more effectively to save time and reduce costs. Integrated voice, video, and Web
conferences can be set up and attended in a single step from IP phones, instant messaging clients,
Web browsers, and Microsoft Outlook and IBM Lotus Notes calendars.
•
Mobility solutions—Cisco Unified Communications extends rich call control and collaboration
services to facilitate easy collaboration among mobile workers on campus or on the move. By
anchoring communications in the network, Cisco Mobile Unified Communications solutions
connect different mobile worker types and workspaces, provide a consistent collaboration
experience regardless of location, maintain business continuity and compliance, and take advantage
of least-cost routing of mobile communications over the education network. Cisco Mobile Unified
Communications solutions support a wide range of popular handheld platforms, enabling workers
to communicate quickly and easily using their familiar mobile equipment.
•
Application development—Schools may operate in unique educational environments that require
specialized applications. To meet these needs, Cisco provides a versatile service creation platform,
enabling schools and partners to rapidly and easily develop and deliver innovative, media-rich and
Web-rich applications. The platform also allows organizations to easily blend unified
communications capabilities with existing business process systems.
For more information, refer to the following URL:
http://www.cisco.com/en/US/netsol/ns818/networking_solutions_program_home.html
IP Video Surveillance
Video surveillance systems have proven their value in a wide range of applications. In educational
environments, video documentation of critical incidents enhances student safety and better protects
valuable assets. However, traditional analog CCTV surveillance systems have many limitations—they
are unable to store recorded video in local and remote locations or provide video access to mobile or
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remote users. Having recognized the cost savings, productivity improvements, and enhanced
communications provided by IP networks, many administrators would like to apply these technology
benefits to video surveillance systems.
Network-centric video surveillance components include:
•
Cisco Video Surveillance Manager enables education administrators and security personnel to view,
manage, and record video locally and remotely using the IP network and a standard Internet
browser. Video can be securely accessed anywhere, at any time, enabling faster response,
investigation, and resolution of incidents. Video can be recorded and stored locally and off-campus,
allowing it to be managed and aggregated with video from multiple locations. VSM interoperates
with a wide range of third-party vendor devices and applications such as video analytics, providing
a solution that is cost-effective to deploy, fits budgets, and enables new capabilities. As a result,
student safety can be enhanced and valuable assets can be better protected through the video
documentation of critical incidents.
•
Cisco Video Surveillance Media Server—Media Server is a highly scalable and reliable video
management platform that manages, replicates, distributes, and archives video streams.
•
Cisco Video Surveillance Operations Manager—This Web-based user interface authenticates and
manages access to video feeds. It is a centralized administration tool for the management of Media
Server hosts, Virtual Matrix hosts, cameras, encoders, and viewers.
•
Cisco Video Surveillance Media Virtual Matrix—Virtual Matrix monitors video feeds in command
center and other 24-hour monitoring environments. It allows operators to control the video being
displayed on multiple local and remote digital monitors.
For more information, refer to the following URL:
http://www.cisco.com/en/US/netsol/ns929/networking_solutions_sub_program_home.html.
Digital Media Systems
The Cisco Digital Media System is a comprehensive suite of digital signage, desktop video, and
enterprise TV applications that you can manage centrally:
•
Cisco digital signage provides scalable centralized management and publishing of compelling
digital media to networked, on-premise digital signage displays. It enables the dissemination of
district news and emergency Information to large screens connected to the school’s existing
network. You can deliver the same content to all signs in the district, such as reminders of testing
dates, or deliver different content to different schools. Within the same school, you might display
the cafeteria menu on one digital sign and information about an upcoming bond election on signs
where parents pick up their children.
•
Cisco desktop video gives students access to high-quality and compelling videos on demand (VoDs)
and live Webcasts at their desktops. Digital Media can be browsed, searched, and viewed over the
network through a unique, easy-to-use Cisco video portal experience—anywhere, anytime.
•
Cisco enterprise TV is an interactive application that enables schools to deliver on-demand video
and broadcast live TV channels over an IP network to digital displays. On-screen menus and
program guides give users access to enterprise TV content and organizations can customize lineups
and create their own content libraries. Users can navigate through channel menus and select from
on-demand content with a remote control or other remote devices.
Components of Cisco’s digital media system include:
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•
Cisco Digital Media Manager is the central management application for all Cisco Digital Media
System products. It is used to manage, schedule, and publish compelling digital media for digital
signage, enterprise TV, and desktop video. As an integrated part of the Cisco Digital Media System,
this Web-based media management application enables content owners to easily upload, catalogue,
edit, package, and publish digital media content for live or on-demand playback.
•
Cisco Video Portal allows users to easily browse, search, and view digital media interactively on
the desktop. It provides secure login, customizable playlists, search, advanced player controls,
full-screen playback, slide synchronization, viewer questions support, and a secure usage-reporting
tool. It supports established video formats such as Windows Media, Flash, and MPEG/H.264.
•
Cisco Digital Media Players are highly reliable, IP-based hardware endpoints that enable digital
signage and Enterprise TV through the ability to play high-definition live and on-demand video,
motion graphics, Web, and dynamic content on digital displays. The Digital Media Player hardware
options include support for standard-definition and high-definition MPEG-2 and MPEG-4/H.264,
Flash, RSS, and other Web formats and dynamic data.
•
Cisco LCD Professional Series Displays are an integral part of the Digital Media System (DMS)
suite of products and are used to display information. Cisco LCD displays are available in different
sizes and models and offer full 1080p resolution.
For more information, refer to the following URL:
http://www.cisco.com/en/US/netsol/ns928/networking_solutions_sub_program_home.html
Mobility
Cisco Mobility and Wireless Solutions for Schools give students and staff the freedom to be anywhere
on campus and still perform all the tasks they would normally do on a classroom’s wired network. The
solutions enable new network connections to PCs, laptops, PDAs, printers, video cameras,
videoconferencing units, IP phones, and other devices, making school resources more widely available
and improving collaboration among students, teachers, parents, and administrators. Mobility products
include:
•
Cisco Aironet Access Points connect Wi-Fi devices to networks in a variety of wireless
environments. Cisco next generation wireless solutions use 802.11n technology to deliver
unprecedented reliability and up to nine times the throughput of 802.11a/b/g networks. Wi-Fi
certified for interoperability with a variety of client devices, these access points support robust
connectivity for both indoor and outdoor environments.
•
Wireless LAN controllers simplify the deployment and operation of wireless networks, helping to
ensure smooth performance, enhanced security, and maximum network availability. Cisco wireless
LAN controllers communicate with Cisco Aironet access points over any Layer 2 or Layer 3
infrastructure to support system-wide wireless LAN (WLAN) functions, such as:
– Enhanced security with WLAN policy monitoring and intrusion detection
– Intelligent radio frequency (RF) management
– Centralized management
– QoS
– Mobility services such as guest access, voice over Wi-Fi, and location services
Cisco wireless LAN controllers support 802.11a/b/g and the IEEE 802.11n draft 2.0 standard, so you can
deploy the solution that meets your individual school requirements. From voice and data services to
location tracking, Cisco wireless LAN controller products provide the control, scalability, security, and
reliability you need to build highly secure, district-wide wireless networks.
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Service Ready Architecture for Schools—Key Services
Cisco Wireless Location Appliance allows school districts to simultaneously track thousands of devices
from within the WLAN infrastructure, bringing the power of a cost-effective, high-resolution location
solution to critical applications such as:
•
High-value asset tracking
•
IT management
•
Location-based security
This easy-to-deploy solution smoothly integrates with Cisco WLAN controllers and Cisco
lightweight access points to track the physical location of wireless devices to within a few meters.
This appliance also records historical location information that can be used for location trending,
rapid problem resolution, and RF capacity management.
•
Cisco Mobility Services Engine is a solution that creates an open platform for the development and
optimization of mobile applications. Designed with extensibility in mind, the platform supports a
suite of software that is designed to create and optimize the performance of mobility applications
by offering a standardized, open method for bridging network and application intelligence. The
Mobility Services Engine allows schools to simplify the deployment of mobility applications across
the district and introduces a structured way for partners to develop industry-specific mobility
applications.
For more information, refer to the following URL:
http://www.cisco.com/en/US/netsol/ns820/networking_solutions_program_home.html
Security
Cisco security solutions combine multiple security technologies along with embedded security in Cisco
routing and switching platforms to protect school network infrastructures. Some of these technologies
include:
•
Firewall solutions for network security
•
A reliable firewall is the hallmark of a secure network. Networks support sensitive, crucial
applications and processes and provide a common infrastructure for converged data, voice, and
video services; firewall security is a primary concern. Instead of providing only point products that
set a base level of security, Cisco embeds firewall security throughout the network and integrates
security services in all of its products. Firewall security becomes a transparent, scalable, and
manageable aspect of the business infrastructure.
•
Cisco NAC Appliance is an easily deployed Network Admission Control (NAC) product that uses
the network infrastructure to enforce security policy compliance on all devices seeking to access
network computing resources. With NAC Appliance, network administrators can authenticate,
authorize, evaluate, and remediate wired, wireless, and remote users and their machines prior to
network access. It identifies whether networked devices such as laptops, IP phones, or game
consoles are compliant with your network’s security policies and repairs any vulnerabilities before
permitting access to the network.
•
Cisco Secure ACS is a highly scalable, high-performance access policy system that centralizes
authentication, user access, and administrator access policy and reduces the administrative and
management burden. Cisco Secure ACS is a central point for administering security policy for users
and devices accessing the network. Cisco Secure ACS supports multiple and concurrent access
scenarios including:
•
Device administration—Cisco Secure ACS authenticates network administrators, authorizes
commands, and provides an audit trail.
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Conclusion
•
Remote access—Cisco Secure ACS works with VPN and other remote network access devices to
enforce access policies.
•
Wireless—Cisco Secure ACS authenticates and authorizes wireless users and hosts and enforces
wireless-specific policies.
•
802.1x LAN—Cisco Secure ACS supports dynamic provisioning of VLANs and access control lists
(ACLs) on a per user basis and 802.1x with port-based security.
•
Network admission control—Cisco Secure ACS communicates with posture and audit servers to
enforce admission control policies.
For more information, refer to the following URL:
http://www.cisco.com/en/US/netsol/ns744/networking_solutions_program_home.html
Conclusion
The Cisco Service Ready Architecture for Schools is a network roadmap for school districts to utilize to
enable 21st century education for students and teachers. It is built by combining an understanding of the
current and future school district network needs with the best technology available, while considering
the technical and financial constraints faced by school districts.
To learn more about the Cisco Service Ready Architecture for Schools, refer to the following URL:
http://www.cisco.com/go/education
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3
Network Foundation Design
This chapter describes the Schools Service Ready Architecture network design, which is a well designed
and tested network architecture that is flexible, and cost effective to support a wide range of educational
services. Key features of the Schools SRA include:
•
High Availability
•
Single Fabric—Multi Services
•
Differentiated Services
•
Layer 2 and Layer 3 Access
This chapter provides design guidance to build a highly resilient, manageable and cost-effective school
network which provides a solid in foundation for seamless integration and operation of applications and
network services. The network has been specifically designed to meet the challenges of the education
environment.
Building Unified Schools Network Infrastructure
Cisco has years of experience developing high performance, highly available, multi service networks.
The key to developing a robust design is applying a proven methodology. The following design
principles were applied to develop the School SRA network architecture:
•
Hierarchy
– Clarifies the role of each device in each tier
– Simpler to deploy, operate, and manage the network
– Reduces fault domains at every tier
•
Modularity
– Enables growing the network on demand basis
•
Resiliency
– Meet users expectation of network always being available.
•
Flexibility
– Allows intelligent traffic load-sharing by using all network resources
The Unified Schools network is designed to be highly available, and cost effective, while delivering
capabilities necessary to enable advanced services, such as IP telephony, video, security, wireless LANs.
The network design includes the following key features;
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•
Hierarchical design with collapsed Core
•
Quality-of-service (QoS) to ensure real-time data (telephony, video) are given higher priority
•
Application of resilient design principles
•
Multi cast
•
Routed access
•
Redundancy
Hierarchical Network Design
The three-tier hierarchical model (see Figure 3-1) is the approach typically employed to achieve a high
performance, highly available, scalable network design. This design employs the four key design
principles of hierarchy, modularity, resiliency and flexibility.
Figure 3-1
Three-Tier Hierarchical Model
Core
Distribution
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Access
Each layer in the three-tier hierarchical model has a unique role to perform:
•
Access Layer—The primary function of an access-layer is to provide network access to the end user.
This layer often performs OSI Layer-2 bridge function that interconnects logical Layer-2 broadcast
domains and provides isolation to groups of users, applications, and other endpoints. The
access-layer interconnects to the distribution layer.
•
Distribution Layer—Multi-purpose system that interfaces between access layer and core layer.
Some of the key function for a distribution layer include the following:
– Aggregate and terminate Layer-2 broadcast domains
– Provide intelligent switching, routing, and network access policy function to access the rest of
the network.
– Redundant distribution layer switches provides high availability to the end-user and equal-cost
paths to the core. It can provide differentiated services to various class-of-service applications
at the edge of network.
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•
Core Layer—The core-layer provides high-speed, scalable, reliable and low-latency connectivity.
The core layer aggregates several distribution switches that may be in different buildings. Backbone
core routers are a central hub-point that provides transit function to access the internal and external
network.
Table 3-1 lists the key functions of each layer.
Table 3-1
Key Functions of Hierarchical Network Layer Devices
Key Function
Access
Distribution
Network Transit
Rest of the network.
Internal and External network
Intelligent Services
PoE, IEEE 802.1AD,
Mobility, AutoQoS,
Auto-SmartPort Macro(ASP)
Route optimization
Core
Network and System Virtualization
Layer-2 Interconnect
Forwarding Decision
Layer 2/Layer 3
Layer 3
Security Services
CISF, 802.1x, NAC, ACL etc. CISF, ACL, Route Filter,
CoPP etc.
ACL, Route Filter, CoPP etc.
QoS Services
Classification, Marking,
Policer and Queueing
Classification, Marking, and Queueing
To learn more about typical network designs, refer to the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/campover.html
Figure 3-2 illustrates a sample network diagram for a multi-building large school design.
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Figure 3-2
Multi Building Large School Network Design
Building B –
Library and
Communication Center
Building C –
Administration and
Data Center
Access
Distribution
Core
Distribution
Building D –
Social Science
and Health
Building E –
Arts and
Technology
Building F –
History and
Geography
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Access
Collapsed Core Network Design
The three-tier hierarchical design maximizes performance, network availability, and the ability to scale
the network design. Most school campus' do not grow significantly larger over time, and most school
campus' are small enough to be well served by a two-tier hierarchical design, where the core and
distribution layers are collapsed into one layer. The primary motivation for the collapsed core design is
reducing network cost, while maintaining most of the benefits of the three-tier hierarchical model.
Deploying a collapsed core network results in the distribution layer and core layer functions being
implemented in a single device. The collapsed core/distribution device must provide the following:
Note
•
High speed physical and logical paths connecting to the network
•
Layer-2 aggregation and demarcation point
•
Define routing and network access policies
•
Intelligent network services—QoS, Network virtualization, etc.
If the district office or a school campus has multiple buildings, and is expected to grow over time, then
implementing the three-tier hierarchical model is a better choice.
Figure 3-3 illustrates a sample network diagram for a single building school district office.
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Figure 3-3
Collapsed Core School District Office Network Design
Access
Floor 6 –
Social Science and Health
Internet
Floor 5 –
Arts and Technology
Floor 4 –
History and Geography
Floor 2 –
Administration and Data Center
Distribution/
Core
PSTN
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Floor 3 –
Library and Communication Center
WAN
District Office Network Design
If the district office has multiple buildings or the district office site is expected to grow significantly over
time, then implementing the three-tier hierarchical model is a good choice. For smaller district office
sites that are unlikely to grow significantly, the collapsed core model is more cost effective. The School
Service Ready Architecture uses the collapsed core network design in the district office.
The collapsed core network (see Figure 3-4) may be deployed with redundant core/distribution router,
or consolidated core/distribution router.
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Figure 3-4
Collapsed Core District Office School Network Models
Campus Deployment Design – 1
Internet
WAN
PSTN
Campus Deployment Design – 2
Internet
WAN
Distribution/Core
PSTN
Distribution/Core
Access
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Access
The redundant design is more complex, because all of the core/distribution functions must be
implemented on two routers in a complimentary fashion. To learn more about the redundant designs,
refer to High Availability School Recovery Analysis Design Guide at the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/HA_recovery_DG/campusRecovery.ht
ml
The School SRA district office is designed with a consolidated core/distribution router to maximize
performance, while keeping costs affordable (design 2). The consolidated collapsed core model has the
following benefits:
•
Simplifies network protocols (eases network operations)
•
Enables symmetric forwarding paths
•
Delivers deterministic network recovery performance
With this design, the default behavior of Layer-2 and Layer-3 network control protocols is to create a
redundant view between two systems. The core router builds a ECMP routing topology which results in
symmetric forwarding paths beyond the district office.
Default Layer-2 configuration eliminates the need for FHRP, automatically eliminating the asymmetric
forwarding behavior which causes unicast flooding in the network. This simplifies the network
operation, since there is no need to configure or tune FHRP protocols.
The disadvantage of this Layer-2 network design is that the network is under-utilized. This is due to the
way Layer-2 protocols are designed to build loop-free network topologies. When two Layer-2 bridges
are directly connected, the STP protocol will block low-priority STP physical port in the forwarding
table. Figure 3-5 illustrates the control-plane, and the forwarding-plane for this design.
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Figure 3-5
Design Model 2 – Developing Control and Forwarding Paths
Control-Plane
Internet
WAN
Forwarding-Path
PSTN
Internet
WAN
PSTN
Per Physical
Port Layer 3
IGP adjacency
STP Primary
Root
STP Primary
Root
Per Physical
Port Layer 2
STP operation
VLAN
10
VLAN
20
VLAN
30
Layer 2 Trunk Port
Layer 3 Rounded Port
Standby Firewall Port
STP Block Port
VLAN
10
VLAN
20
Bi-directional Traffic Port
Non-Forwarding Port
VLAN
30
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Per Physical
Port Layer 3
IGP adjacency
This design suffers from two challenges:
•
Multiple routing adjacencies between two Layer-3 systems. This configuration doubles the
control-plane load between each of the Layer-3 devices. It also uses more system resources like CPU
and memory to store redundant dynamic-routing information with different Layer-3 next-hop
addresses connected to same router.
•
As depicted in Figure 3-5, STP protocol blocks one of the physical ports in the Layer-2 network.
Since this design employs point-to-point links between the collapsed core and peer devices, the
solution is to tune the network to enable a single control plane, to improve forwarding efficiency and
resource utilization. The recommendation is to aggregate all physical ports into a single logical
channel-group. This logical aggregated Ethernet bundle interface is known as EtherChannel.
EtherChannel Fundamentals
EtherChannel provides inverse-multiplexing of multiple ports into a single logical port to a single
neighbor. This technique increases bandwidth, link efficiency, and resiliency. EtherChannel technology
operates on the MAC layer. Upper layer protocols require a single instance to operate over the logical
interface. EtherChannel provides efficient network operation and graceful recovery to higher layer
protocols during bundle port failure and restoration.
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The control-plane depicted in Figure 3-5 builds redundant Layer- 2 or Layer-3 network information over
each physical links. Each device builds common network prefix entries with a different next-hop path
pointing to same next hop device. Implementing EtherChannel results in a network topology with a
single destination entry for single next-hops, via the egress logical EtherChannel port. EtherChannel
reduces storing redundant network entries in the database and forwarding tables, which automatically
improves network convergence times and system resources utilization.
EtherChannel helps improve the overall network stability and availability. Failure of individual physical
link will cause network topology recomputation, restoration, and may be rerouted. Such process requires
CPU interruption that could impact the overall application performance. EtherChannel significantly
simplifies the network response to a individual link failure. If an individual link in EtherChannel fails,
the interface will not trigger any network topology changes. All underlying hardware changes remain
transparent to higher-layer protocols, thus minimizing impact to network and application performance,
and improving network convergence. Figure 3-6 illustrates how enabling EtherChannel in Layer-2 and
Layer-3 network simplifies control-plane and forwarding-plane.
Figure 3-6
Design Model 2 – Optimized Control and Forwarding Paths with EtherChannel
Control-Plane
Internet
WAN
Forwarding-Path
PSTN
Internet
WAN
PSTN
Single Layer 3
IGP adjacency
STP Primary
Root
STP Primary
Root
Single Layer 2
STP operation
VLAN
10
VLAN
20
VLAN
30
Layer 2 Trunk Port
Layer 3 Rounded Port
Standby Firewall Port
VLAN
10
VLAN
20
Bi-directional Traffic Port
VLAN
30
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Single Layer 3
IGP adjacency
Resilient Distributed System
The consolidated core/distribution layer may become a single-point-of-failure (SPOF) in the network. A
software upgrade or a route-processor failure may cause network outage for minutes.
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The school SRA uses the Cisco Catalyst 4500 with next-generation Supervisor-6E in the consolidated
core/distribution layer. It is chosen for its price performance, and the high availability features within
the device. The Cisco Catalyst 4500 switch supports redundant supervisor engines and provides Stateful
Switchover (SSO) and Non-Stop Forwarding (NSF) capabilities. SSO ensures the Layer-2 and Layer-3
protocol state-machines and network forwarding entries on the standby supervisor engine are
maintained, and can quickly assume control-plane responsibilities and gracefully restore the
control-plane in the event of a primary supervisor failure. While the control-plane is gracefully
recovering, the NSF function continues to switch traffic in hardware.
The Cisco Catalyst 6500 platform is an enterprise-class system providing integrated network services
for large scale and high-speed networks. For large, multi building sites, or in situations where future
scalability is important, the Catalyst 6500 is a better choice for core/distribution layer switch. The design
principles remain the same when deploying a Catalyst 6500.
District Office Access-Layer Edge Services
The access layer is the first tier or edge of the network. It is the layer where end-devices (PCs, printers,
cameras, etc.) attach to the school network. It is also the layer where devices that extend the network out
one more level are attached; IP phones and wireless access points (APs) are examples of devices that
extend the connectivity out from the access switch. The wide variety of devices that can connect and the
various services and dynamic configuration mechanisms required, make the access layer the most
feature-rich layer of the school network. Figure 3-7 illustrates a district office network deployment with
various types of trusted and untrusted endpoints.
Figure 3-7
Access-Layer Trust Boundary and Network Control Services
Core
Distribution/Core
Network
Control
Services
Access
Trust
Boundary
IP
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Wired/Wireless
Trusted/Untrusted
Endpoints
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Table 3-2 examples of the types of services and capabilities that need to be defined and supported in the
access layer of the network.
Table 3-2
Access-layer Services and Capabilities
Service Requirements
Service Features
Discovery and Configuration Services
802.1AF, CDP, LLDP, LLDP-MED
Integrated Security Services
IBNS (802.1X), CISF – Port-Security, DHCP Snooping, DAI and IPSG
Network Identity and Access
802.1X, MAB, Web-Auth
Application Recognition Services
QoS marking, policing, queueing, deep packet inspection NBAR
Intelligent Network Control Services
PVST+, Rapid PVST+, EIGRP, OSPF, DTP, PAgP/LACP, UDLD, FlexLink,
Portfast, UplinkFast, BackboneFast, LoopGuard, BPDUGuard, Port Security,
RootGuard
Energy Efficient Services
Power over Ethernet, EnergyWise, Energy efficient systems
Management Services
Auto-SmartPort Macro, Cisco Network Assistant
The access layer provides the intelligent demarcation between the network infrastructure and the
computing devices that use the infrastructure. It provides network edge security, QoS, and policy trust
boundary. It is the first point of negotiation between the network infrastructure and the end devices
seeking access to the network.
A flexible network design, and the demand for mobility are two requirements which drive the access
layer design. A flexible network design allows any legitimate device to be connected anywhere in the
network (eg IP Phone, printer, video surveillance camera, digital signage, etc). Network users expect to
be able to move around their devices (laptops, PDAs, printers, etc) and gain network access wherever
necessary.
In order to allow devices to be moved within the school and ensure they associate with the correct
network policies and services; the following access services are integrated into the school architecture:
•
Ability to physically attach to the network and be associated with or negotiate the correct Layer-1
and Layer-2 network services—PoE, link speed and duplex, subnet (VLAN or SSID)
•
Ability to provide device identification and, where needed, perform network access authentication
•
Ability for the network to apply the desired QoS policies for the specific user, device or traffic flow
(such as RTP streams)
•
Ability for the network to apply the desired security policies for the specific user or device
•
Ability for the network and device to determine and then register the location of the attaching device
•
Ability for the device to negotiate and register the correct end station parameters (such as DHCP),
as well as register for any other necessary network services (such as register for Unified
Communications presence and call agent services)
The basic steps for deploying edge access switch features are as follows:
Step 1
Configure the baseline switching foundation
Step 2
Protect the network infrastructure
Step 3
Protect the end devices and their application data flows
Step 4
Apply the necessary network policies (QoS) to provide for the required service levels.
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Step 5
Create the final template macro to allow for simplified configuration
Design details, explaining how to select the features needed for a given deployment, and how to
implement the features is provided in Chapter 9, “Access Layer Security Design.”
Access-Layer Network Control Services
Properly designing the distribution block ensures the stability of the overall architecture. In the collapsed
core model, the access-distribution block includes the access and distribution layers. Each of these layers
has specific service and feature requirements. The network control plane choice (i.e., routing or spanning
tree protocols) are central to determining how the distribution block fits within the overall architecture.
The school SRA includes two designs for configuring the access-distribution block: multi-layer and
routed-access. See Figure 3-8.
Figure 3-8
Access-Distribution Deployment Model
Multi-Layer
Routed-Access
Distribution/Core
Distribution/Core
Layer 3
Access
VLAN
10
VLAN
20
Layer 2 Trunk Port
VLAN
10
VLAN
20
Layer 3 Rounded Port
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Layer 2
Access
While both of these designs use the same basic physical topology and cabling plant, there are several key
differences:
•
Where the Layer-2 and Layer-3 boundaries exist
•
How the network redundancy is implemented
•
How load-balancing works
A complete configuration description of each access-distribution block model is provided in “Logical
Multi-Layer Network” section on page 3-28 and the “Deploying Routed-Access Network” section on
page 3-33 of this document.
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Resilient Access-Layer Network and System
The access-layer provides endpoint connectivity to the rest of the network. Typical access switches like
the Cisco Catalyst 2900 Series and Cisco Catalyst 3500 Series switches becomes single-point-of-failure
(SPOF), if the hardware fails or if there is a software upgrade. Disrupting communication to mission
critical endpoints (e.g., physical security camera) may be unacceptable.
School SRA is designed with 2 to 4 uplink ports for each access switch, providing link-failure protection.
For mission critical endpoints, School SRA employs the Cisco StackWise or StackWise Plus solution in
the access. It is designed to physically stack and interconnect multiple Layer-2 or Layer-3 switches using
special cables. Stacking multiple switches into a logical ring creates a single unified and resilient
access-layer network topology (see Figure 3-9). The Cisco Catalyst 2975 StackWise can be deployed in
Layer-2 network domain and the Cisco Catalyst 3750-E StackWise or StackWise Plus is deployed for
routed access implementations.
Figure 3-9
Resilient, Scalable and Efficient Access-Layer Network Design
Core
Distribution/Core
Link Protection –
Resilient Logical Link
Distributed Layer 2 EtherChannel Uplink
Cross-StackWise Ring link
Node Protection –
Catalyst 3750-E/2975
StackWise Ring
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Access
District Office Data Center Network Design
The data center is a central location which houses servers and storage. These resources must be available
to users throughout the Schools Service Ready Architecture. The data center may be collocated at the
district office, or in a nearby site. Typically, school districts are unable to afford redundant WAN links
between the data center and the school sites. This makes the design vulnerable to service outage at the
school site, in the event of WAN link failure. The Schools Service Ready Architecture recommends
which services should be placed in the centralized data center, and which services should be distributed
(i.e., hosted at each school site). The key criteria to consider when making this decision include:
•
Scalability—The compute capacity and storage capacity of the centralized data center must be
sufficient to handle peak loads.
•
Network Load—The overall network design, from data center to School Site must have enough
capacity to carry the anticipated traffic (data and control traffic) to ensure good application
performance.
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•
Redundancy—A WAN link failure will result in service outage between data center and the School
Site.This can impact network data services and can expose security issue.
•
Synchronization—Some applications which are hosted locally will require content synchronization
with a centralized server.This can often be scheduled for off hours, to avoid adding traffic to WAN
links during normal working hours.
Table 3-3 provides a sample list of centralized and distributed servers.
Table 3-3
Sample List of Centralized and Distribution Servers
Data Center Model
Server Function
Deployment Location
Centralized
Database server(i.e., Oracle, Sybase, etc)
District Office Data Center
Cisco Unified Call Manager
Cisco Presence Server
Cisco Digital Media Manager (DMM)
E-mail Messaging Server
Distributed
Hosted services – Web, FTP, DHCP, DNS, NTP
Access-Control – Cisco Access Control Server
District Office and School Data
Center
Cisco Video Surveillance Operation Management
Media Storage Server
School Site Network Design
The School Service Ready Architecture includes two school site designs. One for larger schools, and
another for medium to smaller schools. The typical school site is a single building with a limited
population which makes the collapsed core network design a suitable choice.
School Collapsed Core Network Design
The key criteria to consider when designing a school network are the network size, bandwidth capacity
and high-availability requirements. The School Service Ready Architecture includes two models: one
for smaller schools and another for larger schools. Both designs offer high capacity, performance, and
availability. Figure 3-10 illustrates the two school network design models.
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Figure 3-10
Collapsed Core School Network Models
School Campus Design Model – 1
WAN
PSTN
Cisco
Catalyst
4500-E
Distribution/Core
School Campus Design Model – 2
WAN
PSTN
Cisco Catalyst
3750-E
Stackwise
Distribution/Core
Access
Access
VLAN
10
VLAN
20
VLAN
30
VLAN
30
Layer 2 Trunk Port
Layer 3 Rounded Port
Layer 2 Trunk Port
Layer 3 Rounded Port
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VLAN
10
VLAN
20
Design Model - 1 is for a larger school site. The network design is the same as the district office network
design, with the same performance capabilities, scalability options, and high availability features.
Design Model - 2 is for a medium to small school site. The primary difference is the use of the Cisco
Catalyst 3750-E Stack Wise Plus switch in the collapsed core/distribution layer. The 3750-E Stack Wise
Plus deploys up to nine 3750-E switches in a ring topology as a single virtual switch. Each chassis
replicates the control functions, and provides packet forwarding. If the master switch fails, another
switch will quickly assume the control plane 'master' function. This results in a cost effective, high
performance, scalable solution, with built in resiliency.
•
Performance—Provides wire-rate network connection to access switches
•
Scalable—May deploy up to 9 switches in a stack to aggregate a reasonable number of access
switches
•
High Availability—Stack provides a virtual switch, with distributed control plane, delivering
subsecond system failure recovery times
The Cisco 3750-E StackWise Plus delivers high performance routing and switching capability and robust
IOS feature support. The control-plane and forwarding paths functions for the Cisco 3750-E StackWise
Plus in the collapsed core network design remain the same. However, the switching architecture of the
Cisco 3750-E StackWise differs significantly from the high-end distributed and modular switch
platforms like Cisco Catalyst 4500 and 6500 Series switches. For more information about the Cisco
3750-E StackWise architecture, refer to the following URL:
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http://www.cisco.com/en/US/partner/prod/collateral/switches/ps5718/ps5023/prod_white_paper09186
a00801b096a_ps7077_Products_White_Paper.html
School Access-Layer Design
The access-layer network designate the school site is the same as at the district office. The same devices
are available, and the same design choices may be deployed to achieve a high performance, secure and
resilient access layer. To simplify the overall system design, and network operations, it is recommended
to use consistent design and platform selections in the access-layer role, at the district office and school
sites. This will allow a common configuration template and simplify operations and troubleshooting
procedures.
Deploying Schools Foundation Services
The two-tier hierarchical design delivers a reliable and resilient, scalable, and manageable foundation
network design. This subsection provides design and deployment guidelines for the school core layer,
and access-distribution block.
The access-distribution block, as described in the “District Office Data Center Network Design” section
on page 3-12, uses a combination of Layer-2 and Layer-3 switching to provide a balance of policy and
access controls, availability, and flexibility in subnet allocation and VLAN usage. Deployment
guidelines are provided to implement multi-layer, and routed access designs in the access-distribution
block.
Implementing EtherChannel in School Network
Etherchannel is used throughout the network design, and the implementation guidelines are the same for
multi-layer, and routed-access models, and in the WAN edge design. As recommended in the
“EtherChannel Fundamentals” section on page 3-7, there should be single logical point-to-point
EtherChannel deployed between collapsed core and access-layer. The EtherChannel configuration on
each end of the link in the access-distribution block must be consistent to prevent a link bundling
problem. EtherChannels use link bundling protocols to dynamically bundle physical interfaces into a
logical interface.
The following are the benefits of building EtherChannel in dynamic mode:
•
Ensure link aggregation parameters consistency and compatibility between switches.
•
Ensure compliance with aggregation requirements.
•
Dynamically react to runtime changes and failures on local and remote Etherchannel systems
•
Detect and remove unidirectional links and multi-drop connections from the Etherchannel bundle.
EtherChannels can be deployed in dynamic or static modes. Both EtherChannel modes can coexist in a
single system; however, the protocols (PagP, LACP) can not interoperate with each other.
•
Cisco proprietary link aggregation—Cisco's implementation of Port Aggregation group Protocol
(PAgP) is supported on all the Cisco Catalyst platforms. The PAgP protocol is not supported when
the Cisco Catalyst 2975 or 3750 Series switches are deployed in StackWise mode. The PAgP
protocol can operate in the different channel-group modes shown in Table 3-4 to initialize link
bundling process.
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Table 3-4
Cisco’s Proprietary PAgP Channel-Group Mode
channel-group
mode
Distribution
Access-switch and WAN Edge
EtherChannel State
auto
auto
Non-Operational
desirable (recommended)
desirable (recommended)
Operational State
desirable
auto
auto
desirable
•
Table 3-5
IEEE 802.3ad link aggregation—Link Aggregation Control Protocol (LACP) is based on IEEE
802.3ad specification to operate in vendor-independent network environment. LACP link bundling
protocol is developed with same goal as Cisco's PAgP. Cisco Catalyst switches in StackWise mode
must use LACP to dynamically bundle. LACP can operate in the following different channel-group
modes to initialize the link bundling process. See Table 3-5.
IEEE 802.3ad LACP channel-group mode
channel-group mode
Distribution
Access-switch and WAN Edge
EtherChannel State
passive
passive
Non-Operational
active
active
Operational State
(recommended)
(recommended)
active
passive
passive
active
•
Static Mode—Each system statically bundles selected physical ports into a logical port-channel. In
static mode, Etherchannel consistency check is not performed between two switches, which may
lead to network protocol instability or network outage due to mis-configuration. This mode is not
recommended and should only be considered when EtherChannel is required but side of the link
does not support PAgP or LACP link aggregation protocol.
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Figure 3-11
Implementing EtherChannel in District Office School Network
WAN
PSTN
cr24-3750ME-do
cr26-2851-do
cr24-4507-DO
Distribution/Core
Access
cr24-2960-do
cr25-3750s-do
L2 EtherChannel
L3 EtherChannel
227542
cr24-3560r-do
The following sample configuration shows how to build Layer-2 and Layer-3 EtherChannel
configuration and bundling physical ports into appropriate logical EtherChannel-group:
cr24-4507-DO#config t
Enter configuration commands, one per line. End with CNTL/Z.
cr24-4507-DO(config)#interface Port-channel1
cr24-4507-DO(config-if)# description Connected to cr24-3750ME-DO
cr24-4507-DO(config-if)#
cr24-4507-DO(config-if)#interface Port-channel11
cr24-4507-DO(config-if)# description Connected to cr24-2960-DO
cr24-4507-DO(config-if)# switchport
cr24-4507-DO(config-if)#
cr24-4507-DO(config-if)#interface Port-channel16
cr24-4507-DO(config-if)# description Connected to cr25-3750s-DO
cr24-4507-DO(config-if)# switchport
cr24-4507-DO(config-if)#
cr24-4507-DO(config-if)#interface range Gig 3/3 , Gig 4/3
cr24-4507-DO(config-if-range)# description Connected to cr24-3750ME-DO
cr24-4507-DO(config-if-range)# channel-protocol pagp
cr24-4507-DO(config-if-range)# channel-group 1 mode desirable
cr24-4507-DO(config-if-range)#
cr24-4507-DO(config-if-range)#interface range Gig 1/1 , Gig 2/1
cr24-4507-DO(config-if-range)# description Connected to cr24-2960-DO
cr24-4507-DO(config-if-range)# channel-protocol pagp
cr24-4507-DO(config-if-range)# channel-group 11 mode desirable
cr24-4507-DO(config-if-range)#
cr24-4507-DO(config-if-range)#interface range Gig 1/6 , Gig 2/6
cr24-4507-DO(config-if-range)#description Connected to cr26-3750s-DO
cr24-4507-DO(config-if-range)# channel-protocol lacp
cr24-4507-DO(config-if-range)# channel-group 16 mode active
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Enabling EtherChannel on each switch endpoint will automatically form a logical connection and can be
verified using following CLI command:
cr24-4507-DO#show etherchannel summary | inc
Group Port-channel Protocol
Ports
1
Po1(RU)
PAgP
Gi3/3(P)
11
Po11(SU)
PAgP
Gi1/1(P)
16
Po16(SU)
LACP
Gi1/6(P)
Po
Gi4/3(P)
Gi2/1(P)
Gi2/6(P)
EtherChannel Load Balancing
EtherChannel load-sharing is based on a polymorphic algorithm. On per protocol basis, load sharing is
done based on source XOR destination address or port from Layer 2 to 4 header and ports. For higher
granularity and optimal utilization of each member-link port, an EtherChannel can intelligently
load-share egress traffic using different algorithms. EtherChannel load balancing method support varies
on Cisco Catalyst platforms. Table 3-6 summarizes the currently supported EtherChannel
load-balancing methods.
Table 3-6
EtherChannel Load Balancing Support Matrix
Packet Type
Classification
Layer
Load Balancing Mechanic
Supported Cisco Catalyst Platform
Non-IP
Layer 2
src-dst-mac
29xx, 35xx, 3750, 4500
IP
src-mac
dst-mac
src-dst-mac
IP
Layer 3
src-ip
dst-ip
src-dst-ip
IP
Layer 4
src-port
4500
dst-port
src-dst-port
EtherChannel load-balancing mechanisms function on a per-system basis. By default, EtherChannel will
use the hash computation algorithm. The network administrator can globally configure the load
balancing mechanism. In Cisco Catalyst platforms, EtherChannel load balancing is performed in
hardware and it cannot perform per-packet-based load balancing among different member links within
EtherChannel. Bandwidth utilization of each member-link may not be equal in default load balancing
mode. The Ether Channel load balancing method should be changed to source and destination IP address
based throughout the district office and school network for the following reasons:
•
One cannot optimize load balancing using hash tuning in a general network deployment model. This
is due to variations in application deployment and usage patterns.
•
EtherChannel does not take into account the bandwidth of each flow. Instead, it relies on the
statistical probability that the load is equally distributed across the links of the port-channel group,
given a large number of flows of relatively equal bandwidths. However, this may not always be true.
Tuning the load-balancing to source-and-destination IP address allows for statistically-superior
load-distribution. When loads are balanced in this manner, packets belonging to a single flow will
retain their packet order. See Figure 3-12.
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Figure 3-12
EtherChannel Load-Balance Method
WAN
PSTN
EtherChannel Load
Balance Hash
src-dst-ip
Edge
src-dst-ip
Distribution/Core
227543
Access
src-dst-ip
The following output provides sample configuration guideline for changing the default port-channel
load-balance setting to source-destination-ip based. Aside from Layer-2 or Layer-3 EtherChannel
mode, similar configuration must be applied on each system in the access-distribution block and WAN
edge.
cr24-4507-DO(config)#port-channel load-balance src-dst-ip
cr24-4507-DO#show etherchannel load-balance
EtherChannel Load-Balancing Configuration:
src-dst-ip
EtherChannel Load-Balancing Addresses Used Per-Protocol:
Non-IP: Source XOR Destination MAC address
IPv4: Source XOR Destination IP address
IPv6: Source XOR Destination IP address
The following additional EtherChannel design and configuration must be taken into consideration for an
optimal EtherChannel design:
•
Enable single EtherChannel between access-layer and distribution system. Enabling more than a
single Ether Channel in a collapsed core network design imposes the same limitations as discussed
in non-EtherChannel scenario in Figure 3-5.
•
For optimal load sharing and hashing computation, it is recommended to bundle the number of
physical ports in powers of 2 (i.e., 2, 4, and 8).
•
EtherChannel is a logical interface in Cisco Catalyst platform. EtherChannel scalability in collapsed
core and distribution must be taken into account. The Cisco Catalyst 4500 can support up to 64
EtherChannels, whereas the Cisco Catalyst 3750 StackWise can support up to 48 EtherChannels
per-system.
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Deploying Core Network Layer
This section provides implementation and best practice guidelines for deploying the core-layer in both
the district office and school site. Proper design of the core network layer ensures reachability,
transparency and availability. This section focuses on building a unicast routing topology.
Routing Protocol
Enabling routing in the school network is a simple task. However, the network physical layout must be
carefully planned and designed to ensure flexible, stable and efficient routing. Developing a hierarchical
network addressing scheme enables a stable, efficient and scalable design.
•
Hierarchical network addressing—Structured IP network addressing in school LAN/WAN network
is a must to make network scalable, stable.
•
Routing protocol—Cisco IOS supports wide range of Interior Gateway Protocol (IGP). It is
recommended to deploy a single choice of routing protocol across the school infrastructure. This
solution guide does not recommended any particular IGP to deploy in the school architecture as it
significantly varies based on different network infrastructure. However it will provide some key
points to be considered when selecting unicast routing protocol.
•
Hierarchical routing domain—Routing protocols must be designed in a hierarchical model that
allows network to scale and operate with greater stability. Building routing boundaries and
summarizing the network addresses minimizes topology size and synchronization procedure, which
improves the overall network resource utilization and reconvergence.
Routing Protocol Selection Criteria
•
Efficient address allocation—Hierarchical addressing enables efficient use of address space, since
groups are contiguous.
•
Improves routing efficiency—Using contiguous ip addresses enables efficient route summarization.
Route summarization simplifies the routing database, and computations during topology changes.
This reduces the network bandwidth used by the routing protocol, and improves routing protocol
performance by reducing network convergence time.
•
Improves system performance—Hierarchical, contiguous ip addressing reduces router memory
usage by eliminating dis-contiguous and non-summarized route entries. It saves on CPU cycles
needed to compute the routing database during topology changes. This contributes to a more stable
routing network, and simplifies the task of network operations and management.
Cisco IOS supports many Interior Gateway Protocols (IGP), including EIGRP and OSPF, either of which
are suitable for large network deployments. While OSPF is capable of greater scale, it is also more
complex, and hence more difficult to configure, operate and manage. The Schools Service Ready
Architecture is designed and validated using EIGRP, since it is a stable, high performance, efficient
protocol, which is simple to implement and manage. The same design principles apply whether using
EIGRP or OSPF.
Table 3-7 lists some of the EIGRP and OSPF side-by-side feature comparison information.
Table 3-7
EIGRP and OSPF feature comparison chart
Feature
EIGRP
OSPF
Classless Routing
Both routing protocols support classless routing that allows to partition networks into VLSM.
Loop Prevention
Built-in mechanic to prevent routing loop in network.
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Table 3-7
EIGRP and OSPF feature comparison chart (continued)
Robust metric
Aggregated link Bandwidth + Delay
Aggregated link Bandwidth
Efficient routing
Partial update
Multi-access routing
adjacency
Full-mesh
Hub-n-spoke
Hierarchical Routing
No. All routers considered in backbone.
Non-backbone or routers in non-transit
path can be deployed in Stub role.
OSPF area is divided in multiple routing domains.
Backbone area maintains complete summarized
network topology; non-backbone area can be transit
or non-transit OSPF routers.
Network convergence
Both routing protocol offers rapid network recovery during link failure.
Graceful-Restart Support Yes
Yes. Cisco and IETF based
Route Summarization
Flexibility to manual summarized on any
routing node.
Can only be performed on ABR or ASBR
Load-Balancing
Support equal and un-equal cost load
balancing
Equal-cost path only.
Standard
Cisco proprietary
IETF standard
Designing End-to-End EIGRP Routing Domain
EIGRP is a balanced hybrid routing protocol that builds neighbor adjacency and a flat routing topology
on a per-autonomous-system (AS) basis. The LAN/WAN infrastructure of School Service Ready
Architecture should be deployed in a single EIGRP AS to prevent route redistribution, loops, and other
problems that may occur due to misconfiguration. See Figure 3-13.
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Figure 3-13
School
End-to-End EIGRP Routing Design in School Architecture
EIGRP AS – 100
School
EIGRP AS – 100
EIGRP AS – 100
PSTN
WAN
PSTN
District Office
EIGRP AS – 100
227544
Internet
Implementing EIGRP Routing
The district office is the central hub in the network. Each school site is connected to the district office
over the WAN infrastructure. The district office network includes the Internet gateway and provides
access to the central data-center. Since both the school sites, and district office networks use the
collapsed core design, the routing configuration of the core routers is the same.
The following is a sample configuration to enable EIGRP routing process at the edge of the district office
collapsed core network. EIGRP is enabled in the school site network with the same configuration:
cr24-4507-DO(config)#interface Loopback0
cr24-4507-DO(config-if)# ip address 10.125.100.1 255.255.255.255
cr24-4507-DO(config-if)#interface Port-channel1
cr24-4507-DO(config-if)# description Connected to cr24-3750ME-DO
cr24-4507-DO(config-if)#no switchport
cr24-4507-DO(config-if)# ip address 10.125.32.4 255.255.255.254
cr24-4507-DO(config-if)#interface Port-channel2
cr24-4507-DO(config-if)# description Connected to cr24-2851-DO
cr24-4507-DO(config-if)#no switchport
cr24-4507-DO(config-if)# ip address 10.125.32.6 255.255.255.254
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cr24-4507-DO(config)#interface Vlan200
cr24-4507-DO(config-if)# description Connected to cr24_ASA_Inside_Port
cr24-4507-DO(config-if)# ip address 10.125.33.9 255.255.255.0
cr24-4507-DO(config)#router eigrp 100
cr24-4507-DO(config-router)# no auto-summary
cr24-4507-DO(config-router)# eigrp router-id 10.125.100.1
cr24-4507-DO(config-router)# network 10.125.0.0 0.0.255.255
cr24-4507-DO#show ip eigrp neighbor port-channel 13
EIGRP-IPv4:(100) neighbors for process 100
H
Address
Interface
Hold Uptime
(sec)
1
10.125.33.10Vl200111d00h
1
200 0 171
0
10.125.32.7Po2161d02h
1
200 0 304
2
10.125.32.5Po1141d02h
2
200 0 25038
SRTT
RTO
(ms)
Q Seq
Cnt Num
EIGRP Adjacency Protection
Implementing summarization in the EIGRP routing process automatically enables EIGRP routing
process on each interface that is summarized. By default, the router transmits and accept EIGRP hello
messages from remote device to form an adjacency on all EIGRP enabled interfaces. This behavior needs
to be modified to ensure a secure, efficient and stable routing design:
•
System efficiency—There is no need to send EIGRP hellos on an interface where there is no trusted
EIGRP neighbor. In a large network, sending EIGRP hello messages periodically to such interfaces
consumes unnecessary CPU resource. EIGRP route processing should only be enabled on interfaces
where trusted network devices are connected. All other interfaces can be suppressed in passive
mode. The following configuration shows how to automatically disable EIGRP processing on all the
Layer-3 interfaces and only enable on the trusted interface. This design principle must be applied
on each EIGRP router, including distribution and core routers:
cr24-4507-DO(config)#router eigrp 100
cr24-4507-DO(config-router)# network 10.125.0.0 0.0.255.255
cr24-4507-DO(config-router)# passive-interface default
cr24-4507-DO(config-router)# no passive-interface Port-channel1
cr24-4507-DO(config-router)# no passive-interface Port-channel2
cr24-4507-DO(config-router)# no passive-interface Vlan200
cr24-3560r-DO#show ip eigrp interface
EIGRP-IPv4:(100) interfaces for process 100
Interface
Vl2001
Po1 1
Po2 1
Xmit
Queue
Peers
Un/Reliable SRTT
0/01 0/1
50
0
0/02 0/1
50
0
0/04 0/1
50
0
Mean
Pacing Time
Multicast Pending
Un/Reliable
Flow Timer Routes
cr24-4507-DO#show ip protocols | inc Passive|Vlan
Passive Interface(s):
Vlan1
Vlan101
Vlan102
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Vlan103
Vlan104
•
Network Security—Sending unnecessary EIGRP Hello messages opens a security vulnerability in
two ways. An attacker can detect EIGRP operation and send flood of EIGRP hello messages to
destabilize the network. Or an attacker could establish a “fake” EIGRP adjacency and advertise a
best metric default-route into the network to black hole and compromise all critical traffic. Each
EIGRP system should implement MD5 authentication, and each EIGRP neighbor should validate
MD5 authentication is enabled on adjacent systems. This provides a secure method of transmitting
and receiving routing information between devices in the network. Following is a sample
configuration to enable EIGRP neighbor authentication using MD5:
– Distribution
cr24-4507-DO(config)#key chain eigrp-key
cr24-4507-DO(config-keychain)# key 1
cr24-4507-DO(config-keychain-key)#
key-string <password>
cr24-4507-DO(config)#interface Port-channel1
cr24-4507-DO(config-if)# description Connected to cr24-3750ME-DO
cr24-4507-DO(config-if)# ip authentication mode eigrp 100 md5
cr24-4507-DO(config-if)# ip authentication key-chain eigrp 100 eigrp-key
– WAN Aggregation
cr24-3750ME-DO(config)#key chain eigrp-key
cr24-3750ME -DO(config-keychain)# key 1
cr24-3750ME -DO(config-keychain-key)#
key-string <password>
cr24-3750ME
cr24-3750ME
cr24-3750ME
cr24-3750ME
•
-DO(config)#interface Port-channel1
-DO(config-if)# description Connected to cr24-4507-DO
-DO(config-if)# ip authentication mode eigrp 100 md5
-DO(config-if)# ip authentication key-chain eigrp 100 eigrp-key
System Stability—As mentioned in Table 8, EIGRP allows network administrator to summarize
multiple individual and contiguous networks into a single summarized network before advertising
to neighbors. Route summarization improves performance, stability, and convergence times, and it
makes the network easier to manage operate and troubleshoot.
EIGRP provides the flexibility to summarize at any point in the network. Proper design requires
determining which routers will serve as Aggregators, and advertise summarized network information to
peers. Routers which connect multiple access devices, or connect to the WAN edge should be made
Aggregators. Figure 3-14 provides an example Schools SRA network with route aggregator devices
identified with the direction of route summarization illustrated.
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Figure 3-14
Route Aggregator and Summary Route Advertisement Direction
Aggregator
Aggregator
WAN
Aggregator
227545
Aggregator
The following sample configuration shows EIGRP route summarization. In this example, the entire
access-layer network is summarized into a single classless network and advertised to the WAN edge, the
ASA firewall and the PSTN gateway:
•
Distribution
cr24-4507-DO(config)#interface Port-channel1
cr24-4507-DO(config-if)# description Connected to cr24-3750ME-DO
cr24-4507-DO(config-if)# ip summary-address eigrp 100 10.125.0.0 255.255.0.0
cr24-4507-DO(config-if)#interface Port-channel2
cr24-4507-DO(config-if)# description Connected to cr24-2851-DO
cr24-4507-DO(config-if)# ip summary-address eigrp 100 10.125.0.0 255.255.0.0
cr24-4507-DO(config-if)#interface Vlan200
cr24-4507-DO(config-if)# description Connected to cr24_ASA_Inside_Port
cr24-4507-DO(config-if)# ip summary-address eigrp 100 10.125.0.0 255.255.0.0
cr24-4507-DO#show ip protocols | inc Address|10.125.0.0
Address Family Protocol EIGRP-IPv4:(100)
Address Summarization:
10.125.0.0/16 for Port-channel1, Vlan200, Port-channel2
•
WAN Aggregation
Verifying district office EIGRP summarized route status at WAN aggregation layer as follows:
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cr24-3750ME-DO#show ip route 10.125.0.0 255.255.0.0
Routing entry for 10.125.0.0/16
Known via "eigrp 100", distance 90, metric 1792, type internal
Redistributing via eigrp 100
Last update from 10.125.32.4 on Port-channel1, 1d04h ago
Routing Descriptor Blocks:
* 10.125.32.4, from 10.125.32.4, 1d04h ago, via Port-channel1
Route metric is 1792, traffic share count is 1
Total delay is 20 microseconds, minimum bandwidth is 2000000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1
Tuning EIGRP Protocol Timers
EIGRP uses Hello messages to form adjacencies and determine if neighbors are alive. EIGRP adjacency
is declared down if it fails to receive Hello messages within the Hold down timer interval. All the
prefixes discovered from a dead neighbor are removed from the routing table. By default, EIGRP
transmits a Hello message every 5 seconds to notify neighbors that it is still alive. The EIGRP hold-down
timer gets reset each time the router receives a EIGRP Hello message. Default EIGRP adjacency
Hold-down timer is 15 seconds.
Lowering EIGRP hello and hold-down timer intervals improves network convergence times (i.e. time to
detect and respond to an outage). For Schools SRA design it is recommended to use the default EIGRP
Hello and Hold timer values for the following reasons:
•
EtherChannel Benefits—EIGRP operates over the Layer-3 EtherChannel. In the event of a single
member-link failure condition, layer 2 will respond more quickly than the routing protocol, and
switchover traffic from the impacted link to an alternate member link. EIGRP routing is not
impacted by individual link member and no change in the routing table is required. Thus reducing
the EIGRP timers will not result in quicker convergence, and may adversely impact system stability.
•
High-Availability—The Cisco Catalyst 4500, 37xx (non-Stack Wise) and 35xx series layer 3
switches support Stateful-Switch Over (SSO) which enables a backup supervisor to gracefully
assume the active role while maintaining adjacency with neighbors, during a supervisor failure
condition. The backup supervisor requires sufficient time to detect a failure and initiate graceful
recovery with neighbors. Implementing aggressive timers may abruptly terminate adjacency and
cause network outage before a stateful switch over is accomplished. Thus, default EIGRP Hello and
Hold timers are recommended on Cisco Catalyst 4500, 37xx (non-Stackwise) and 35xx Series
Layer-3 platforms.
Deploying Multi-Layer Network
Multilayer design is one of the two access-distribution block designs included in the Schools Service
Ready Architecture. This section provides implementation and best practices guidelines the multi-layer
design. The deployment and configuration guidelines for the multi-layer access-distribution block are
the same for both district office and school site networks.
Spanning-Tree in Multilayer Network
Spanning Tree (STP) is a Layer-2 protocol that prevents logical loops in switched networks with
redundant links. The School SRA design uses Etherchannel (point-to-point logical Layer-2 bundle)
connection between access-layer and distribution switch which inherently simplifies the STP topology
and operation. In this design, the STP operation is done on a logical port, therefore, it will be assigned
automatically in forwarding state.
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Over the years, the STP protocols have evolved into the following versions:
•
Per-VLAN Spanning Tree Plus (PVST+)—Provides a separate 802.1D STP for each active VLAN
in the network.
•
IEEE 802.1w – Rapid PVST+—Provides an instance of RSTP (802.1w) per VLAN. It is easy to
implement, proven in large scale networks that support up to 3000 logical ports and greatly improves
network restoration time.
•
IEEE 802.1s – MST—Provides up to 16 instances of RSTP (802.1w) and combines many VLANs
with the same physical and logical topology into a common RSTP instance.
Following is the example configuration to enable STP protocol in multi-layer network:
Distribution
cr24-4507-DO(config)#spanning-tree mode rapid-pvst
cr24-4507-DO#show spanning-tree summary | inc mode
Switch is in rapid-pvst mode
Access-Layer Switch
cr24-2960-DO(config)#spanning-tree mode rapid-pvst
Default STP parameters optimize the network for packet forwarding. Best practice design includes
hardening STP parameters in the access and distribution switch to protect against STP misconfiguration,
or malicious user by deploying spanning-tree toolkit in the access-distribution block. See Figure 3-15.
Figure 3-15
Hardening Spanning-Tree Toolkit in Multi-Layer Network
Spanning-Tree
Root Switch
Distribution/Core
Root-Guard
Access
Edge-Port
Layer 2 Trunk Port
227546
BPDU-Guard
The following is the configuration deploys spanning-tree toolkit in the access-distribution block:
Distribution
cr24-4507-DO(config)#spanning-tree vlan 1-4094 root primary
cr24-4507-DO(config)#interface range Gig 1/1 – 2 , Gig 2/1 – 2
cr24-4507-DO(config)#spanning-tree guard root
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Access
cr26-2975-DO(config)#interface GigabitEthernet1/0/1
cr26-2975-DO(config-if)#description CONNECTED TO UNTRUSTED-PC
cr26-2975-DO(config-if)#spanning-tree bpduguard enable
Other STP Toolkit Consideration
When the access-distribution block multi-layer design is deployed using the recommended best
practices, it automatically minimizes the need for deploying the following additional spanning-tree
toolkit technologies:
•
UplinkFast—Improves the network convergence time by providing direct access to the root switch
link failure. UplinkFast is not necessary in this design, because there is no alternate STP path and
RSTP protocol natively includes rapid recovery mechanism.
•
BackBone Fast—Provides rapid convergence from indirect Layer-2 link failures in a redundant
distribution switch configuration. This is feature is not necessary for the same reason as stated for
UplinkFast.
•
LoopGuard—Protects Layer-2 networks from loops that occur due to any malfunction that prevents
normal BPDU forwarding. A STP loop is created when a blocking port in a redundant topology
erroneously transitions to the forwarding state. This usually happens because one of the ports in a
physically redundant topology (not necessarily the blocking port) stopped receiving BPDUs.
Because there is single point-to-point STP forwarding port in this design, enabling Loopguard does
not provide any additional benefit. UDLD protocol must be implemented to prevent STP loop that
may occur in the network due to network malfunction, mis-wiring, etc.
Logical Multi-Layer Network
VLAN assignment can have a significant impact on network performance and stability. There are three
basic ways to assign VLANs within the access-distribution block.
Flat Logical Network Design
Spanning a single VLAN across multiple access-layer switches is much simpler with a single collapsed
core-distribution device versus a design with redundant distribution devices. The flat multi-layer design
has a single VLAN across multiple access devices, as shown in See Figure 3-16.
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Figure 3-16
Multi-Layer Flat Network design
Multi-Layer – Flat Network
Distribution/Core
VLAN
10
Admin
VLAN
10
Library
VLAN
10
Arts
227547
Access
A flat multi-layer network deployment introduces the following challenges:
•
Scalability—Spanning the same VLAN in different access-layer switches will create a large Layer-2
broadcast domain that dynamically discovers and populates MAC address entries for endpoints that
may not need to communicate. In a large network, this may become a scalability issue (i.e. memory
required to hold large CAM table).
•
Performance—In a large network, spanning a large number of broadcast domains will impact the
performance of all network devices in the access-distribution block, because the switch will have to
process many more broadcast packets such as ARP.
•
Security—The flat muli0layer design widens the fault domain which increases possible attacks to a
larger number of users.The number of users is not necessarily due to the number switches spanned
and applications during DoS or viruses attack.
Segmented Logical Network Design
Best practice design includes identifying meaningful groups within the user community, and assigning
a unique VLAN to each group. These groups may be departments, user groups, or any other logical
grouping of users. Enabling a unique VLAN for each group will segment the network and build a logical
network structure. All network communication between groups will pass through the routing and
forwarding policies defined at the distribution layer. See Figure 3-17.
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Figure 3-17
Multi-Layer Segmented Network Design
Multi-Layer – Segmented Network
Distribution/Core
Access
VLAN
20
Library
VLAN
30
Arts
227548
VLAN
10
Admin
A segmented VLAN design is the solution to the challenges described in the flat network design. VLAN
segmentation improves the scalability, performance, and security of the network.
Hybrid Logical Network Design
The segmented logical network design improves scalability, performance and security, and addresses the
challenges of a flat network design. In real world deployments, there is usually a need for some users or
applications to communicate with all users (eg system administrator). The hybrid network design is the
segmented design, with the addition of a exceptional VLAN which spans the entire access-distribution
block. See Figure 3-18.
Figure 3-18
Multi-Layer Hybrid Network Design
Multi-Layer – Hybrid Network
Distribution/Core
Access
Library
VLAN
20
Arts
VLAN
30
VLAN 900
227549
Admin
VLAN
10
Cisco recommends the segmented VLAN network design and optionally hybrid network for centralized
users or applications that requires distributed function across the access-layer network.
Following are the sample VLAN configuration steps in the access and the distribution layer switches.
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Distribution
VLAN Trunking Protocol (VTP) is a Cisco proprietary Layer -messaging protocol that manages the
addition, deletion, and renaming of VLANs on a network-wide basis. Cisco's VTP simplifies
administration in a switched network. VTP can be configured in three modes: server, client, and
transparent. Set the VTP domain name and change the mode to the transparent mode as follows:
cr24-4507-DO(config)#vtp domain District-Office
cr24-4507-DO(config)#vtp mode transparent
cr24-4507-DO(config)#vlan 10
cr24-4507-DO(config-vlan)#name
cr24-4507-DO(config-vlan)#vlan
cr24-4507-DO(config-vlan)#name
cr24-4507-DO(config-vlan)#vlan
cr24-4507-DO(config-vlan)#name
cr24-3750-Admin-Dept
20
cr24-3560-Library-Dept
30
cr24-2960-Arts-Dept
Access
Set VTP domain name and change the mode to the transparent mode as follows:
cr24-3750-DO(config)#vtp domain District-Office
cr24-3750-DO(config)#vtp mode transparent
cr24-3750-DO(config)#vlan 10
cr24-3750-DO(config-vlan)#name cr24-3750-Admin-Dept
Implementing Layer 2 Trunk
In a typical network design, a single access switch will have more than one VLAN, for example a Data
VLAN and a Voice VLAN. The network connection between Distribution and Access device is a trunk.
VLAN's tag their traffic to maintain separation between VLANS across the trunk. By default on Cisco
Catalyst switches, the native VLAN on each layer 2 trunk port is VLAN 1, and cannot be disabled or
removed from VLAN database. The native VLAN remains active on all access switches layer 2 ports.
There are two choices for encapsulating the tagged VLAN traffic on the trunk: IEEE 802.1Q or Cisco
ISL. It is recommended to implement trunk encapsulation in static mode instead of negotiating mode, to
improve the rapid link bring-up performance. Not all Cisco Catalyst platforms support ISL
encapsulation; therefore IEEE 802.1Q is recommended, and validated in the access and distribution
switches.
Enabling the Layer-2 trunk on a port-channel, automatically enables communication for all of the active
VLANs between the access and distribution. This means an access-switch which has implemented, for
example, VLANs 10 to 15, will receive flood traffic destined for VLANs 20 to 25, which are
implemented on another access switch. RPVST +, using logical ports, operates on a per-VLAN basis to
load balance traffic. In a large network, it is important to limit traffic on Layer-2 trunk ports to only the
assigned VLANS, to ensure efficient and secure network performance. Allowing only assigned VLANs
on a trunk port automatically filters rest.
The default native VLAN must be properly configured to avoid several security risks—Attack, worm and
virus or data theft. Any malicious traffic originated in VLAN 1 will span across the access-layer
network. With a VLAN-hopping attack it is possible to attack a system which does not reside in VLAN
1. Best practice to mitigate this security risk is to implement a unused and unique VLAN ID as a native
VLAN on the Layer-2 trunk between the access and distribution switch. For example, configure VLAN
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802 in the access-switch and in the distribution switch. Then change the default native VLAN setting in
both the switches. Thereafter, VLAN 802 must not be used anywhere for any purpose in the same
access-distribution block.
Following is the configuration example to implement Layer-2 trunk, filter VLAN list and configure the
native-VLAN to prevent attacks on port channel interface. When the following configurations are
applied on port-channel interface (i.e., Port-Channel 11), they are automatically inherited on each
bundled member-link (i.e., Gig1/1 and Gig2/1):
Distribution
cr24-4507-DO(config)#vlan 802
cr24-4507-DO(config-vlan)#name Admin-Hopping-VLAN
cr24-4507-DO(config)#interface Port-channel 11
cr24-4507-DO(config-if)# description Connected to cr24-3750-DO
cr24-4507-DO(config-if)# switchport
cr24-4507-DO(config-if)# switchport mode trunk
cr24-4507-DO(config-if)# switchport trunk allowed vlan 101-110,900
cr24-4507-DO(config-if)# switchport trunk native vlan 802
cr24-4507-DO#show interface port-channel 11 trunk
Port
Po11
Mode
on
Encapsulation
802.1q
Status
trunking
Native vlan
802
Port
Po11
Vlans allowed on trunk
101-110,900
Port
Po11
Vlans allowed and active in management domain
101-110,900
Port
Po11
Vlans in spanning tree forwarding state and not pruned
101-110,900
Access-switch
cr24-3750-DO(config)#vlan 802
cr24-3750-DO(config-vlan)#name Admin-Hopping-VLAN
cr24-3750-DO(config)#interface Port-channel 1
cr24-3750-DO(config-if)# description Connected to cr24-4507-DO
cr24-3750-DO(config-if)# switchport
cr24-3750-DO(config-if)# switchport mode trunk
cr24-3750-DO(config-if)# switchport trunk allowed vlan 101-110,900
cr24-3750-DO(config-if)# switchport trunk native vlan 802
Unidirectional Link Detection
UDLD is a Layer 2 protocol that works with the Layer 1 features to determine the physical status of a
link. At Layer 1, auto-negotiation takes care of physical signaling and fault detection. UDLD performs
tasks that auto-negotiation cannot perform, such as detecting the identity of neighbors and shutting down
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misconnected ports. When both auto-negotiation and UDLD are enabled, Layer 1 and Layer 2 detection
works together to prevent physical and logical unidirectional connections and the malfunctioning of
other protocols.
Copper media ports use Ethernet link pulse as a link monitoring tool and are not susceptible to
unidirectional link problems. Because one-way communication is possible in fiber-optic environments,
mismatched transmit/receive pairs can cause a link up/up condition even though bidirectional
upper-layer protocol communication has not been established. When such physical connection errors
occur, it can cause loops or traffic black holes. UDLD functions transparently on Layer-2 or Layer-3
physical ports. UDLD operates in one of two modes:
•
Normal mode—If bidirectional UDLD protocol state information times out; it is assumed there is
no-fault in the network, and no further action is taken. The port state for UDLD is marked as
undetermined. The port behaves according to its STP state.
•
Aggressive mode—If bidirectional UDLD protocol state information times out, UDLD will attempt
to reestablish the state of the port, if it detects the link on the port is operational. Failure to
reestablish communication with UDLD neighbor will force the port into the err-disable state. That
must be manually recovered by user or the switch can be configured for auto recovery within
specified interval of time.
Following is the configuration example to implement UDLD protocol:
Distribution
cr24-4507-DO(config)#interface range Gig 1/2 , Gig 2/2
cr24-4507-DO(config-int)#udld port
cr24-4507-DO#show udld neighbor
PortDevice Name
Device ID
Port IDNeighbor State
-------------------------------- -------- -------------Gi1/2
FOC1318Y06V
1
Gi1/0/49Bidirectional
Gi2/2
FOC1318Y06J
1
Gi3/0/49Bidirectional
Access
cr26-2975-DO(config)#interface Gig 1/0/49 , Gig 3/0/49
cr26-2975-DO(config-if)#description Connected to cr24-4507-DO
cr26-2975-DO(config-if)#udld port
cr26-2975-DO#show udld neighbor
PortDevice Name
Device ID
Port IDNeighbor State
-------------------------------- -------- -------------Gi1/0/49 FOX1216G8LT
1
Gi1/2
Bidirectional
Gi3/0/49 FOX1216G8LT
1
Gi2/2
Bidirectional
Deploying Routed-Access Network
This section provides implementation and best practices guidelines to deploy routed-access in the
access-distribution block. The routed access design moves the boundary between Layer 2 and Layer 3
from the distribution layer to the access layer as seen in Figure 3-19.
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Figure 3-19
Control Function in Multi-Layer and Routed-Access Network Design
Routing
Routing
Layer 3
Distribution/Core
Layer 3
Distribution/Core
STP
Routing
Layer 2
Access
Access
Layer 2
Library
VLAN
20
Arts
VLAN
30
Multi-Layer Network
Admin
VLAN
10
Library
VLAN
20
Arts
VLAN
30
Routed-Access Network
227550
Admin
VLAN
10
Routing in the access-layer simplifies configuration, optimizes distribution performance, and improves
end-to-end troubleshooting tools. Implementing routing in the access-layer replaces Layer-2 trunk
configuration with single point-to-point Layer-3 interface in distribution layer. Placing Layer-3 function
one tier down on access-switches, changes the multilayer network topology and forwarding path.
Implementing Layer-3 function in the access-switch does not require a physical or logical link
reconfiguration; the same EtherChannel in access-distribution block can be used.
At the network edge, Layer-3 access-switches provides an IP gateway and become the Layer-2
demarcation point to locally connected endpoints that could be logically segmented into multiple
VLANs. Following are the benefits of implementing routed-access in the access-distribution block:
•
Eliminates the need to implement STP and the STP toolkit in the distribution layer. As a best
practice, STP toolkit must be hardened at the access-layer.
•
Shrinks the Layer-2 fault domain, which minimizes the number of endpoints affected by a
DoS/DDoS attack.
•
Improves Layer-3 uplink bandwidth efficiency by suppressing Layer-2 broadcasts at the access edge
port.
•
Improves performance by reducing resource utilization in collapsed core-distribution layer. In a
large multilayer network, the aggregation layer may consume more CPU cycles due to the large
number of MAC and ARP discovery and processing and storing required for each end-station.
Routed-access reduces the load of this Layer-2 processing and storage in the distribution layer, by
moving the load to layer-3 access-switches. Figure 3-20 illustrates where Layer-2 and Layer-3
forwarding entry processing and storage takes place when access-distribution block is implemented
as multi-layer versus routed-access network.
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Forwarding entry development in multi-tier network
Distribution/Core
Distribution/Core
MAC
ARP
Route
Route
Access
Access
MAC
Admin
VLAN
10
Library
VLAN
20
Arts
VLAN
30
MAC
ARP
Route
Multi-Layer Network
Admin
VLAN
10
Library
VLAN
20
Arts
VLAN
30
Routed-Access Network
227551
Figure 3-20
While the routed access design is appropriate for many school networks it is not suitable for all
environments. Routed access does not allow a VLAN to span multiple access switches. Refer to
following URL for detailed design guidance for the routed access distribution block design:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/routed-ex.html
Implementing EIGRP Routing in Access-Distribution Block
The School Service Ready Architecture uses EIGRP routing protocol, and all the devices in the LAN
and WAN sub-networks are deployed in a single AS. This subsection focuses on implementing EIGRP
in the access-distribution block. All the deployment and configuration guidelines in this section are the
same for deploying in the district office or school site network.
Following is the example configuration to enable basic EIGRP routing in the distribution layer and in
the access layer:
Distribution
cr24-4507-DO(config)#interface Port-channel13
cr24-4507-DO(config-if)# description Connected to cr24-3560r-DO
cr24-4507-DO(config-if)#no switchport
cr24-4507-DO(config-if)# ip address 10.125.32.0 255.255.255.254
cr24-4507-DO(config)#router eigrp 100
cr24-4507-DO(config-router)# no auto-summary
cr24-4507-DO(config-router)# eigrp router-id 10.125.100.1
cr24-4507-DO(config-router)# network 10.125.0.0 0.0.255.255
cr24-4507-DO#show ip eigrp neighbor port-channel 13
EIGRP-IPv4:(100) neighbors for process 100
H
Address
Interface
Hold Uptime
SRTT
(sec)
(ms)
3
10.125.32.1
Po13
14 00:02:14
2
RTO
Q
Seq
Cnt Num
200
0 385
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Access
cr24-3560r-DO(config)#interface Loopback0
cr24-3560r-DO(config-if)# ip address 10.125.100.4 255.255.255.255
cr24-3560r-DO(config-if)#
cr24-3560r-DO(config-if)#interface Port-channel1
cr24-3560r-DO(config-if)# description Connected to cr24-4507-DO
cr24-3560r-DO(config-if)# no switchport
cr24-3560r-DO(config-if)# ip address 10.125.32.1 255.255.255.254
cr24-3560r-DO(config)#ip routing
cr24-3560r-DO(config)#router eigrp 100
cr24-3560r-DO(config-router)# no auto-summary
cr24-3560r-DO(config-router)# eigrp router-id 10.125.100.4
cr24-3560r-DO(config-router)# network 10.125.0.0 0.0.255.255
cr24-3560r-DO#show ip eigrp neighbor port-channel 1
EIGRP-IPv4:(100) neighbors for process 100
H
Address
Interface
Hold
Uptime
SRTT
RTO
(sec)
(ms)
0
10.125.32.0
Po1
13
00:10:00
1
Q
Seq
Cnt Num
200
0 176
Building EIGRP Network Boundary
EIGRP creates and maintains a single flat routing network topology between EIGRP peers. Building a
single routing domain enables complete network visibility and reach ability between all of the elements
within the network.(access, distribution, core, data center, WAN, etc)
In a tiered design, the access layer always has a single physical or logical forwarding path to the
distribution layer. The access switch will build a forwarding topology pointing to same distribution
switch as a single Layer-3 next-hop. Since the distribution switch provides a gateway function to the
access switch, the routing design can be optimized with the following two techniques to improve
performance and network convergence in the access-distribution block:
•
Deploy Layer 3 access-switch in EIGRP stub mode
•
Summarize network view to Layer-3 access-switch for intelligent routing function
Deploy Layer 3 Access-Switch in EIGRP Stub Mode
The Layer-3 access switch can be deployed to announce itself as a stub router that acts as a non-transit
router and does not connect any other Layer-3 stub or non-stub routers. Announcing itself as a
non-transit stub Layer-3 router is one way to notify the distribution router that it should not include the
Layer-3 access switch in the EIGRP topology recomputation process. This optimized recomputation
process will prevent unnecessary EIGRP network queries, which reduces network traffic, and simplifies
the route computation.
As illustrated in Figure 3-21, implementing EIGRP stub function in the access switches, greatly reduces
the number of EIGRP network queries.
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Figure 3-21
EIGRP Query Path with and without Stub Implementation
EIGRP Query Path without Stub
EIGRP Query Path with Stub
10.100.1.0/24
10.100.1.0/24
Admin
VLAN
10
Library
VLAN
20
Arts
VLAN
30
Admin
VLAN
10
Routed-Access Network
Library
VLAN
20
Arts
VLAN
30
Routed-Access Network
227552
EIRGP
Stub
EIGRP stub router in Layer-3 access-switch can announce routes to a distribution-layer router with great
flexibility.
EIGRP stub router can be deployed to announce routes dynamically discovered or statically configured.
Best practice design is to deploy EIGRP stub router to announce locally learned routes to aggregation
layer.
Following is the example configuration to enable EIGRP stub routing in the Layer-3 access-switch, no
configuration changes are required in distribution system:
Access
cr24-3560r-DO(config)#router eigrp 100
cr24-3560r-DO(config-router)#eigrp stub connected
cr24-3560r-DO#show eigrp protocols detailed
Address Family Protocol EIGRP-IPv4:(100)
EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
EIGRP maximum hopcount 100
EIGRP maximum metric variance 1
EIGRP NSF-aware route hold timer is 240
EIGRP stub, connected
Topologies : 0(base)
Distribution
cr24-4507-DO#show ip eigrp neighbors detail port-channel 13
EIGRP-IPv4:(100) neighbors for process 100
H
Address
Interface
Hold Uptime
SRTT
(sec)
(ms)
1
10.125.32.1
Po13
13 00:19:19
16
Version 12.2/3.0, Retrans: 0, Retries: 0, Prefixes: 11
Topology-ids from peer - 0
RTO
Q Seq
Cnt Num
200 0 410
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Stub Peer Advertising ( CONNECTED ) Routes
Suppressing queries
Summarizing Stub Routed-Access Network
Enabling the EIGRP stub function on the access switch does not change the distribution router behavior
of forwarding the full EIGRP topology table. The Distribution router must be configured to advertise
summarized routes that do not compromise end-to-end reach ability, and help access switches maintain
minimal routing information. In a network with a well designed IP addressing scheme, the aggregation
system can advertise summarized routes in a classless address configuration, that reduce individual
network advertisements, improve network scalability and network convergence. The distribution router
must have full network topology information to ensure efficient reachability paths. Therefore, it is
recommended to summarize at the distribution router, and not summarize at the access-layer.
Route summarization must be implemented on the distribution layer of district office and each school
site network. This includes devices such as the WAN aggregation in the district office. The distribution
router must advertise the following summarized network information to Layer 3 access-switch:
•
Local Network—Distribution router can be implemented in hybrid access-distribution configuration
that interconnects several multi-layer or routed-access enabled access-layer switches. Independent
of route origination source (connected or dynamic route) and network size within the
access-distribution block, the distribution router in district office and school site network must
advertise a single, concise and summarized Layer 3 network to each Layer 3 access-switch and to
core devices.
•
Remote Network—Summarized network will be propagated dynamically across the network. Single
summarization of all remote networks may be advertised to local Layer 3 access-switches, since it
improves bandwidth efficiency. During a network outage, Layer 3 access-switch may drop traffic at
the network edge instead of transmitting it to the distribution router to black hole traffic.
•
WAN Network—Announcing a single summarized WAN network provides flexibility to troubleshoot
and verify network availability.
•
Default Network—When Layer 3 access-switch receives un-known destination traffic from the edge
that does not match any of the above mentioned summarized networks, then it is sent to the
distribution router to make a forwarding decision. The distribution router performs a forwarding
table lookup and may forward to appropriate path or black hole the traffic. In a typical school
environment, a default route is announced by an Internet edge system, to forward all internet traffic.
Distribution router must propagate this default route to the Layer 3 access-switch.
Figure 3-22 illustrates a summarized EIGRP network advertisement, by route aggregation system, that
provides end-to-end internal and external network reachability.
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Figure 3-22
End-to-End Routed-Access Network
10.127.0.0/21
10.125.0.0/16
10.126.0.0/16
10.127.0.0/16
0.0.0.0/0
School
10.127.112.0/21
10.125.0.0/16
10.126.0.0/16
10.127.0.0/16
0.0.0.0/0
Internet
WAN
School
10.126.0.0/16
0.0.0.0/0
District Office
10.125.0.0/16
227553
10.125.0.0/16
10.126.0.0/16
10.127.0.0/16
0.0.0.0/0
Following is configuration example to deploy summarized and filtered Layer-3 network information to
Layer-3 access-switch.
Distribution
interface Port-channel13
description Connected to cr24-3560r-DO
dampening
ip address 10.125.32.0 255.255.255.254
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip summary-address eigrp 100 10.125.0.0 255.255.0.0 5
load-interval 30
carrier-delay msec 0
!
!configure ACL and route-map to allow summarized route advertisement to Layer 3 accessswitch
!
access-list 1 permit 0.0.0.0
access-list 1 permit 10.126.0.0
access-list 1 permit 10.127.0.0
access-list 1 permit 10.125.0.0
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!
route-map EIGRP_STUB_ROUTES permit 10
match ip address 1
!
router eigrp 100
distribute-list route-map EIGRP_STUB_ROUTES out Port-channel13
cr24-4507-DO#show ip protocols | inc Outgoing|filtered
Outgoing update filter list for all interfaces is not set
Port-channel13 filtered by
Access
cr24-3560r-DO#show ip route eigrp
10.0.0.0/8 is variably subnetted, 15 subnets, 4 masks
D
10.126.0.0/16 [90/3328] via 10.125.32.0, 01:37:21, Port-channel1
D
10.127.0.0/16 [90/3584] via 10.125.32.0, 01:37:21, Port-channel1
D
10.125.0.0/16 [90/1792] via 10.125.32.0, 01:34:29, Port-channel1
D*EX 0.0.0.0/0 [170/515072] via 10.125.32.0, 00:03:15, Port-channel1
cr24-3560r-DO#
EIGRP Adjacency Protection
EIGRP adjacency protection guidelines discussed earlier for the core network, apply equally to routed
access in the access-distribution block. The two challenges, system efficiency, and network security also
apply equally to the routed access design, and the same solution is applied:
•
System efficiency—EIGRP hello transmission must be blocked on an interface where there are no
trusted EIGRP neighbors, to reduce CPU utilization and prevent network attacks. EIGRP routing
process should only be enabled on interfaces where trusted school devices are connected. All other
interfaces can be suppressed in passive mode.
Following is the example configuration on Layer-3 access-switch that advertises networks enabled
on SVI interfaces; however, keeps them in passive mode and explicitly allows EIGRP function on
uplink port-channel to distribution router. Same configuration principle must be applied on each
EIGRP router including distribution and core routers:
cr24-3560r-DO(config)#router eigrp 100
cr24-3560r-DO(config-router)# network 10.125.0.0 0.0.255.255
cr24-3560r-DO(config-router)# passive-interface default
cr24-3560r-DO(config-router)# no passive-interface Port-channel1
cr24-3560r-DO#show ip eigrp interface
EIGRP-IPv4:(100) interfaces for process 100
Xmit
Interface
Po1
Peers
1
Un/Reliable
0/0
Queue
SRTT
1
Mean
Pacing Time
Multicast Pending
Un/Reliable
Flow Timer Routes
0/1
50
0
cr24-3560r-DO#show ip protocols | inc Passive|Vlan
Passive Interface(s):
Vlan1
Vlan11
Vlan12
Vlan13
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Vlan14
•
Network Security—EIGRP adjacency between distribution and Layer-3 access-switch must be
secured. Following is the example configuration to enable EIGRP neighbor authentication using
MD5:
Distribution
cr24-4507-DO(config)#key chain eigrp-key
cr24-4507-DO(config-keychain)# key 1
cr24-4507-DO(config-keychain-key)#
key-string <password>
cr24-4507-DO(config)#interface Port-channel13
cr24-4507-DO(config-if)# description Connected to cr24-3560r-DO
cr24-4507-DO(config-if)# ip authentication mode eigrp 100 md5
cr24-4507-DO(config-if)# ip authentication key-chain eigrp 100 eigrp-key
Access
cr24-3560r-DO(config)#key chain eigrp-key
cr24-3560r-DO(config-keychain)# key 1
cr24-3560r-DO(config-keychain-key)#
key-string <password>
cr24-3560r-DO(config)#interface Port-channel1
cr24-3560r-DO(config-if)# description Connected to cr24-4507-DO
cr24-3560r-DO(config-if)# ip authentication mode eigrp 100 md5
cr24-3560r-DO(config-if)# ip authentication key-chain eigrp 100 eigrp-key
Tuning EIGRP Protocol Timers
EIGRP protocol functions the same in routed-access as it does in the core network. It is highly
recommended to retain default EIGRP hello and hold timers on distribution and Layer 3 access-switch
and rely on EtherChannel and SSO-based recovery mechanisms, that offers sub-second network
convergence, during individual link or supervisor failure scenarios.
Deploying Multicast in School Network
Communications in a IP network can be:
•
Unicast—One source sends a message to one destination
•
Broadcast—One source sends a message to all destinations
•
Multicast—One source sends a message to a subset of destinations
IP multicast allows a source to transmit a message as a group transmission to a subset of hosts on the
network. Many collaboration applications, such as video conferencing, distance learning, software
distribution, utilize multicast techniques. IP multicast improves network bandwidth utilization, by
reducing un necessary duplicate traffic. Multicast improves efficiency by reducing data processing on
the source server, and sending a single flow into the network. Multicast packets are replicated in the
network where paths diverge, by Protocol Independent Multicast (PIM) enabled routers, and other
supporting multicast protocols. See Figure 3-23.
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Figure 3-23
Unicast versus Multicast Communication in School Network
Unicast Communication
Multicast Communication
School
District-Office
District-Office
227554
School
Multicast IP Addressing
The Internet Assigned Numbers Authority (IANA) controls the assignment of IP multicast addresses. A
range of class D address space is assigned for IP multicast applications. All multicast group addresses
fall in the range of 224.0.0.0 through 239.255.255.255. In IP multicast packets, the destination IP
address is in the multicast group range, while the source IP address is always in the unicast address
range. The multicast IP address space is further divided into several pools for well-known multicast
network protocols, and inter-domain multicast communications as shown in Table 3-8.
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Table 3-8
Multicast Address Range Assignments
Application
Address Range
Reserved – Link Local Network Protocols
224.0.0.0/24
Globally Scope – Group communication between organization and Internet
224.0.1.0 – 238.255.255.255
Source Specific Multicast (SSM) – PIM extension for one-to-many unidirectional multicast 232.0.0.0/8
communication
GLOP – Inter-domain Multicast group assignment with reserved global Autonomous System 233.0.0.0/8
(AS)
Limited Scope – Administratively scope address that remains constrained within local
organization or AS. Commonly deployed in enterprise, education and other organization.
239.0.0.0/8
For the Schools SRA network design, the multicast IP addresses must be selected from the Limited
Scope pool (239.0.0.0/8).
Multicast Routing Design
Each device between a multicast source and receiver must enable dynamic multicast. The technique for
creating a multicast forwarding table is different than unicast routing and switching techniques.
Multicast requires Multicast Routing Protocol (MRP) and Dynamic Group Membership (DGM) to
enable communication.
Multicast Routing Protocol
IP multicast delivers source traffic to multiple receivers using the least amount of network resources,
without placing additional burden on the source or the receivers. Multicast packet replication in the
network is performed by Cisco routers and switches enabled with Protocol Independent Multicast (PIM)
and other multicast routing protocols.
The network must build a packet distribution tree that specifies a unique forwarding path between the
source subnet and each multicast group members subnet. A primary goal for the tree is to ensure that
only one copy of each packet is forwarded on each branch of the tree. The two basic types of multicast
distribution trees are source trees and shared trees:
•
Source trees—The simplest form of a multicast distribution tree is a source tree, with the source at
the root and the receivers at the branches. Because this tree uses the shortest path through the
network, it is also referred to as a shortest path tree (SPT).
•
Shared trees—A shared tree uses a single common root placed at a chosen point in the network. This
shared root is called a Rendezvous Point (RP).
PIM protocol has two modes which support both types of multicast distribution trees:
•
Dense Mode—This mode assumes that most routers in the network will distribute multicast traffic
to each multicast group. PIM-DM builds distribution trees by initially flooding the entire network
and then pruning back the small number of paths without receivers.
•
Sparse Mode—This mode assumes that relatively few routers in the network will be involved in each
multicast group. The hosts belonging to the group are usually widely dispersed, as would be the case
for most multicast over the WAN. PIM-SM begins with an empty distribution tree and adds branches
only as the result of explicit IGMP requests to join.
It is recommended to deploy multicast in PIM-SM in the Schools SRA. All the recommended platforms
in this design support PIM-SM mode on physical or logical (SVI and EtherChannel) interfaces.
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Dynamic Group Membership
Multicast receiver registration and deletion is done via Internet Group Management Protocol (IGMP)
signaling. IGMP operates between a multicast receiver in the access-layer and a collapsed core router at
the distribution layer in the district office or the school site.
In a multi-layer design, the layer 3 boundary is at the distribution switch. Multi-layer access-switches
do not run PIM, and therefor flood the traffic on all ports. This multi-layer access-switch limitation is
solved by using IGMP snooping feature, which is enabled by default. Best practice is to not disable
IGMP snooping feature.
In a routed-access network design, the Layer-3 boundary is at the access-layer and IGMP
communication is between receiver and access-switch. Along with unicast routing protocol, PIM-SM
must be enabled on the Layer 3 access-switch to communicate with RP in the network.
Figure 3-24 demonstrates multicast source and receiver registration procedure and how shared-tree is
dynamically developed for multicast data delivery.
Figure 3-24
Data
Center
Multicast Source and Receiver Registration Procedure
Distribution/Core
Source
Access
PIM-SM
IGMP
227555
Receiver
Deploying PIM-SM
Multicast data delivery in the network is “connection-oriented”. Multicast communication does not get
triggered by data, instead it requires a registration procedure to detect the source and receiver and
develop the path. Multicast registration procedure is handled by PIM protocol in the network, and when
PIM is deployed in Sparse-Mode registration process is handled by RP.
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PIM-SM Rendezvous Point
PIM-SM distributes information about active sources by forwarding data packets on the shared tree.
Because PIM-SM uses shared trees initially, it requires the use of a RP. It is recommended to deploy the
RP close to the multicast source (collapsed core-distribution router in the district office is a good choice).
Multicast sources centrally deployed in district office will register themselves with the RP and then data
is forwarded down the shared tree to the receivers that could be located anywhere in the network.
PIM-SM supports RP deployment in the following three different modes in the network:
•
Static—As the name implies, RP must be statically identified and configured on each PIM router in
the network. RP load-balancing and redundancy can be achieved using Anycast RP.
•
Auto-RP—Dynamic method to discover and announce RP in the network. Auto-RP implementation
is beneficial when there are multiple RPs and groups that often change in the network. To prevent
network reconfiguration during change, RP mapping agent router must be designated in the network
to receive RP group announcements and arbitrate conflicts. This capability is part of PIM version 1
specification.
•
BootStrap Router (BSR)—Performs same task as Auto-RP but different mechanism. This capability
is pare of PIM version 2 specification. Auto-RP and BSR cannot coexist or interoperate in the same
network.
In a small to mid-size multicast network, static RP configuration is best overall, due primarily to the
amount of administrative overhead that Auto-RP or BSR introduce. Static RP implementation offers
same RP redundancy and load sharing and a simple ACL can be applied to deploy RP without
compromising multicast network security. See Figure 3-25.
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Figure 3-25
PIM-SM Network Design in School Network Infrastructure
PIM-SM
PIM-SM
PIM-SM
PIM-SM
PIM-SM
PIM-SM
WAN
PIM-SM
Source
PIM-SM
RP
PIM-SM
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Data
Center
PIM-SM
Following is an example configuration to deploy PIM-SM RP in the district office. Similar static
PIM-SM configuration must be enabled on each Layer-3 PIM router or an access-switch in the school
sites:
Distribution - RP
cr24-4507-DO(config)#interface Loopback1
cr24-4507-DO(config-if)# description RP
cr24-4507-DO(config-if)# ip address 10.125.100.100 255.255.255.255
cr24-4507-DO(config)#ip multicast-routing
cr24-4507-DO(config)#ip pim rp-address 10.125.100.100
Layer 3 Access
cr24-3560r-DO(config)#ip multicast-routing distributed
cr24-3560r-DO(config)#ip pim rp-address 10.125.100.100
School Core
cr36-3750s-ss100(config)#ip multicast-routing distributed
cr36-3750s-ss100(config)#ip pim rp-address 10.125.100.100
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Upon successful PIM-SM RP implementation throughout the school network, PIM-SM must be enabled
on Layer-3 edge and core network-facing ports. The following sample configuration provides a simple
PIM-SM implementation guideline to be implemented on every intermediate Layer-3 systems between
receiver and source:
Distribution - RP
! District Office – Access Network
cr24-4507-DO(config)#interface range Vlan101 - 140
cr24-4507-DO(config-if-range)# ip pim sparse-mode
! District Office – Data Center Network
cr24-4507-DO(config)#interface range Vlan141 - 150
cr24-4507-DO(config-if-range)# ip pim sparse-mode
! Layer 3 Core and Routed-Access Port-Channel
cr24-4507-DO(config)#interface range Port-channel 1, Port-channel 13, Port-channel 15
cr24-4507-DO(config-if-range)# ip pim sparse-mode
cr24-4507-DO#show ip pim interface
Address
Interface Ver/
Nbr
10.125.32.4
<omitted>
10.125.1.1
Port-channel1v2/S
Vlan101
Query DR
Mode
Count
30
1
1
v2/S 0
30
DR
Intvl Prior
10.125.32.4
1
10.125.1.1
cr24-4507-DO#show ip mroute sparse
(*, 239.192.51.8), 02:33:37/00:03:12, RP 10.125.100.100, flags: SJC
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Vlan111, Forward/Sparse, 02:04:33/00:02:44, H
Vlan101, Forward/Sparse, 02:04:59/00:02:58, H
Port-channel15, Forward/Sparse, 02:04:59/00:02:47, H
Vlan131, Forward/Sparse, 02:04:59/00:02:32, H
Port-channel13, Forward/Sparse, 02:04:59/00:03:12, H
Vlan121, Forward/Sparse, 02:04:59/00:02:14, H
Vlan146, Forward/Sparse, 02:21:26/00:02:01, H
Layer 3 Access
! District Office – Layer 3 Access Network
cr24-3560r-DO(config)#interface range Vlan11 - 20
cr24-3560r-DO(config-if-range)# ip pim sparse-mode
! Routed-Access Port-Channel
cr24-4507-DO(config)#interface Port-channel 1
cr24-4507-DO(config-if)# ip pim sparse-mode
cr24-3560r-DO#show ip pim interface
Address
Interface Ver/
Nbr
10.125.32.1Port-channel1v2/S
10.125.11.1
Vlan11v2/S
1
0
Query DR
DR
Mode
Count Intvl Prior
30
1
10.125.32.0
30
1
10.125.11.1
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Implementing IGMP
By default the Layer-2 access-switch will dynamically detect IGMP hosts and multicast-capable Layer-3
routers in the network. The IGMP snooping and multicast router detection functions on a per VLAN
basis, and is globally enabled by default for all the VLANs. The IGMP configuration can be validated
using the show command on the Layer-2 access-switch:
cr24-2960-DO#show ip igmp snooping
Global IGMP Snooping configuration:
------------------------------------------------IGMP snooping
: Enabled
IGMPv3 snooping (minimal)
: Enabled
Report suppression
: Enabled
TCN solicit query
: Disabled
TCN flood query count
: 2
Robustness variable
: 2
Last member query count
: 2
Last member query interval
: 1000
cr24-2960-DO#show ip igmp snooping mrouter
Vlan
ports
----------101
Po1(dynamic)
102
Po1(dynamic)
cr24-2960-DO#show ip igmp snooping group
Vlan
GroupType
Version
Port List
----------------------------------------------------------------------101
239.192.51.1igmp
v2
Fa0/1, Po1
101
239.192.51.2igmp
v2
Fa0/2, Po1
Multicast routing function changes when the access-switch is deployed in routed-access mode. PIM
operation is performed at the access layer, therefore multicast router detection process is eliminated. The
following output from a Layer-3 switch verifies that the local multicast ports are in router mode, and
provide a snooped Layer-2 uplink port-channel which is connected to the collapsed core router, for
multicast routing:
cr24-3560r-DO#show ip igmp snooping mrouter
Vlan
ports
----------11
Router
12
Router
cr24-3560r-DO#show ip igmp membership | inc Channel|Vl
Channel/Group
Reporter
Uptime
Exp.FlagsInterface
*,239.192.51.8
10.125.11.2000:17:52 02:45 2A
Vl11
*,239.192.51.9
10.125.11.13100:17:52 02:43 2A
Vl12
Multicast Security—Preventing Rogue Source
This section provides basic multicast security configuration guidelines to prevent an unauthorized host
in the network from acting like a rogue source in the network and sending multicast traffic.
In a PIM-SM network, an unwanted traffic source can be controlled with the pim accept-register
command. When the source traffic hits the first-hop router, the first-hop router (DR) creates (S,G) state
and sends a PIM Source Register message to the RP. If the source is not listed in the accept-register filter
list (configured on the RP), then the RP rejects the Register and sends back an immediate Register-Stop
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message to the DR. The drawback with this method of source-filtering is that the pim accept-register
command on the RP, PIM-SM (S,G) state is still created on the source's first-hop router. This can result
in traffic reaching receivers local to the source and located between the source and the RP. Furthermore,
the pim accept-register command works on the control plane of the RP, which could be used to overload
the RP with “fake” register messages, and possibly cause a DoS condition.
Best practice is to apply the pim accept-register command on the RP in addition to other edge-filtering
methods, such as simple data plane ACLs on all DRs and on all ingress points into the network. While
ingress ACLs on the DR are sufficient in a perfectly configured and operated network, best practice
includes configuring the pim accept-register command on the RP in the district office as a secondary
security mechanism in case of misconfiguration on the edge routers.
Following is the sample configuration with a simple ACL which has been applied to the RP to filter only
on the source address. It is also possible to filter the source and the group with the use of an extended
ACL on the RP:
Distribution-RP
cr24-4507-DO(config)#ip access-list extended PERMIT-SOURCES
cr24-4507-DO(config-ext-nacl)# permit ip 10.125.31.80 0.0.0.15 239.192.0.0 0.0.255.255
cr24-4507-DO(config)#ip pim accept-register list PERMIT-SOURCES
Multicast Security—Preventing Rogue RP
Any router can be misconfigured or maliciously advertise itself as a multicast RP in the network. with
the valid multicast group address. With a static RP configuration, each PIM-enabled router in the
network can be configured to use the static RP for the multicast source and ignore any Auto-RP or BSR
multicast router announcement.
Following is the sample configuration that must be applied to each PIM-enabled router in the district
office and school sites, to accept PIM announcements only from the static RP and ignore dynamic
multicast group announcement from any other RP:
Distribution-RP
cr24-4507-DO(config)#ip access-list standard Allowed_MCAST_Groups
cr24-4507-DO(config-std-nacl)# permit 224.0.1.39
cr24-4507-DO(config-std-nacl)# permit 224.0.1.40
cr24-4507-DO(config-std-nacl)# permit 239.192.0.0 0.0.255.255
cr24-4507-DO(config)#ip pim rp-address 10.125.100.100 Allowed_MCAST_Groups override
cr24-4507-DO#show ip pim rp mapping
PIM Group-to-RP Mappings
Acl: Allowed_MCAST_Groups, Static-Override
RP: 10.125.100.100 (?)
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Deploying QoS in School Network
IP networks forward traffic on a best-effort basis by default. The routing protocol forwards packets over
the best path, but offers no guarantee of delivery. This model works well for TCP-based data applications
that adapt gracefully to variations in latency, jitter, and loss. The Schools Service Ready Architecture is
a multi-service network design which supports voice and video as well as data traffic on a single
network. Real time applications (such as voice, video) require packets delivered with in specified loss,
delay and jitter parameters. Quality-of-Service (QoS) is a collection of features which allows the
network to dedicate network resources for higher priority real time applications, while reserving
sufficient network resources to service lower priority traffic. QoS accomplishes this by providing
differentiated services, depending on the traffic type. For a detailed discussion of QoS, refer to the
Enterprise QoS SRND at the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/QoS-SRND-Bo
ok.html
While design principles are common, QoS implementation varies between fixed-configuration switches
and the modular switching platforms like the Cisco Catalyst 4500/6500. This section discusses the
internal switching architecture and the differentiated QoS structure on a per-hop-basis.
QoS in Catalyst Fixed Configuration Switches
The QoS implementation in Cisco Catalyst 2960, 2975, 3560G, 3560-E, 3750G and 3750-E Series
switches is similar. There is no difference in ingress or egress packet classification, marking, queuing
and scheduling implementation among these Catalyst platforms. The Cisco Catalyst switches allow users
to create a policy-map by classifying incoming traffic (Layer 2 to Layer 4). Catalyst switches allow
attaching the policy-map to an individual physical port or to logical interfaces (SVI or port-channel).
This creates a common QoS policy which may be used in multiple networks. To prevent switch fabric
and egress physical port congestion, the ingress QoS policing structure can strictly filter excessive traffic
at the network edge. All ingress traffic from edge ports passes through the switch fabric and congestion
may occur at the egress ports. Congestion in access-layer switch can be prevented by tuning queuing
scheduler and Weighted Tail Drop (WTD) drop parameters. See Figure 3-26.
Receive
Fixed Configuration Catalyst QoS Architecture
Policer
Marker
Policer
Marker
Internal
Ring
Ingress
Queue
NormalQ
SRR
Classify
Priority-Q
Policer
Marker
Policer
Marker
Ingress QoS
Egress
Queue
Q1
Q2
Q3
Q4
Egress QoS
SRR
Transmit
227557
Figure 3-26
The main difference between these platforms is the switching capacity which ranges from 1G to 10G.
The switching architecture and some of the internal QoS structure differs between these switches also.
Following are some important differences to consider when selecting the access switch:
•
The Catalyst 2960 and 2975 do not support multilayer switching and do not support per-VLAN or
per-port/per-VLAN policies.
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•
The Catalyst 2960 and 2975 can police to a minimum rate of 1 Mbps; all other switches within this
product family can police to a minimum rate of 8 kbps.
•
Only the Catalyst 3650-E and 3750-E support IPv6 QoS.
•
Only the Catalyst 3650-E and 3750-E support policing on 10 Gigabit Ethernet interfaces.
•
Only the Catalyst 3650-E and 3750-E support SRR shaping weights on 10 Gigabit Ethernet
interfaces
QoS in Cisco Modular Switches
Cisco Catalyst 4500 and 6500 are high density, resilient switches for large scale networks. The School
Service Ready Architecture uses the Cisco Catalyst 4500 in the district office and larger school site
designs, hence all the QoS recommendations in this section will be based on 4500 architecture. Cisco
Catalyst 4500 Series platform are widely deployed with classic and next-generation supervisors.
The classification function in the classic supervisor module is based on incoming DSCP or CoS setting
in the pack, which was assigned by the access-layer switch. Catalyst 4500 with classic supervisor
performs ingress and egress QoS function based on internal mapping table that performs DSCP, ToS, or
CoS interworking. Classic supervisor relies on trust model configuration; redirection of ingress traffic
to an appropriate queue is based on the trust model defined on the edge port. See Figure 3-27.
Figure 3-27
Catalyst 4500 – Classic Supervisor QoS Architecture
Egress
Queue
Classify
Policer
Marker
Ingress QoS
DBL
Q1
Q2
Q3
Q4
Queuing/ Transmit
Shaping
Egress QoS
227558
Receive
Netflow
Features
SupV-10G
The Cisco Catalyst 4500 with next generation Sup-6E (see Figure 3-28) is designed to offer better
differentiated and preferential QoS services for various class-of-service traffic. New QoS capabilities in
the Sup-6E enable administrators to take advantage of hardware-based intelligent classification and take
action to optimize application performance and network availability. The QoS implementation in Sup-6E
supports Modular QoS CLI (MQC) as implemented in IOS-based routers that overall enhances QoS
capabilities and eases implementation and operations. Following are some of the key QoS features which
differentiate the Sup-6E versus classic supervisors:
•
Trust and Table-Map—MQC based QoS implementation offers a number of implementation and
operational benefits over classic supervisors that rely on Trust model and internal Table-map as a
tool to classify and mark ingress traffic.
•
Internal DSCP—The queue placement in Sup-6E is simplified by leveraging the MQC capabilities
to explicitly map DSCP or CoS traffic in hard-coded egress Queue structure,. For example, DSCP
46 can be classified with ACL and can be matched in PQ class-map of an MQC in Sup-6E.
•
Sequential vs Parallel Classification—With MQC-based QoS classification, the Sup6-E provides
sequential classification rather than parallel. Sequential classification method allows the network
administrator to classify traffic at egress based on the ingress markings.
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Figure 3-28
Catalyst 4500 – Supervisor 6-E QoS Architecture
Ingress QoS
Receive
Marking
Forwarding
Lookup
Classify
Unconditional
Marking
Egress QoS
Policer
Marking
Classify
DBL
Unconditional
Marking
Q1
Q2
Q3
Q4
Q5
Q6
Q7
Q8
Queuing/ Transmit
Shaping
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Policer
QoS Framework
QoS needs to be designed and implemented considering the entire network. This includes defining trust
points, and determining which policies to enforce at each device within the network. Developing the trust
model, guides policy implementations for each device.
Figure 3-29 depicts QoS trust model that guides QoS policy implementation in the district office and
school site networks.
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Figure 3-29
School QoS Framework
Classification,
Marking and
Queueing
Trust (classic sup)
Trust (classic sup)
Classification,
Marking and
Queueing
Queueing and WTD
Trust
Trust, Classification,
Marking, Policing
and Queueing
Queueing and WTD
IP
Trust Boundary
Ingress QoS Ploicy
Egress QoS Ploicy
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Trusted, Conditional-Trusted or Un-Trusted Endpoints
The devices (routers, switches) within the internal network are managed by the system administrator,
and hence are classified as trusted devices. Access-layer switches communicate with devices that are
beyond the network boundary and within the internal network domain. QoS trust boundary at the
access-layer communicates with various devices that could be deployed in different trust models
(Trusted, Conditional-Trusted, or Un-Trusted). This section discusses the QoS policies for the traffic that
traverses access-switch QoS trust boundary. The QoS function is unidirectional; it provides flexibility to
set different QoS polices for traffic entering the network versus traffic that is exiting the network. See
Figure 3-30.
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Figure 3-30
School Network Edge QoS Boundary
Distribution/Core
Ingress QoS Ploicy
Egress QoS Ploicy
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Access
QoS Trust Boundary
The access-switch provides the entry point to the network for end devices. The access-switch must
decide whether to accept the QoS markings from each endpoint, or whether to change them. This is
determined by the QoS policies, and the trust model with which the endpoint is deployed.
End devices are classified into one of three different trust models; each with its own unique security and
QoS policies to access the network:
•
Untrusted—An unmanaged device that does not pass through the network security policies. For
example, student-owned PC or network printer. Packets with 802.1p or DSCP marking set by
untrusted endpoints are reset to default by the access-layer switch at the edge. Otherwise, it is
possible for an unsecured user to take away network bandwidth that may impact network availability
and security for other users.
•
Trusted—Devices that passes through network access security policies and are managed by network
administrator. For example, secure PC or IP endpoints (i.e., servers, cameras, DMP, wireless access
points, VoIP/video conferencing gateways, etc). Even when these devices are network administrator
maintained and secured, QoS policies must still be enforced to classify traffic and assign it to the
appropriate queue to provide bandwidth assurance and proper treatment during network congestion.
•
Conditionally-Trusted—A single physical connection with one trusted endpoint and a indirect
untrusted endpoint must be deployed as conditionally-trusted model. The trusted endpoints are still
managed by the network administrator, but it is possible that the untrusted user behind the endpoint
may or may not be secure. For example, Cisco Unified IP Phone + PC. These deployment scenarios
require hybrid QoS policy that intelligently distinguishes and applies different QoS policy to the
trusted and untrusted endpoints that are connected to the same port.
Deploying QoS
The ingress QoS policy at the access-switches needs to be established, since this is the trust boundary,
where traffic enters the network. The following ingress QoS techniques are applied to provide
appropriate service treatment and prevent network congestion:
•
Trust—After classifying the endpoint the trust settings must be explicitly set by a network
administrator. By default, Catalyst switches set each port in untrusted mode when QoS is enabled.
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•
Classification—IETF standard has defined a set of application classes and provides recommended
DSCP settings. This classification determines the priority the traffic will receive in the network.
Using the IETF standard, simplifies the classification process and improves application and network
performance.
•
Policing—To prevent network congestion, the access-layer switch limits the amount of inbound
traffic up to its maximum setting. Additional policing can be applied for known applications, to
ensure the bandwidth of an egress queue is not completely consumed by one application.
•
Marking—Based on trust model, classification, and policer settings the QoS marking is set at the
edge before approved traffic enters through the access-layer switching fabric. Marking traffic with
the appropriate DSCP value is important to ensure traffic is mapped to the appropriate internal
queue, and treated with the appropriate priority.
•
Queueing—To provide differentiated services internally in the Catalyst switching fabric, all
approved traffic is queued into priority or non-priority ingress queue. Ingress queueing architecture
assures real-time applications, like VoIP traffic, are given appropriate priority (eg transmitted before
data traffic).
Implementing QoS Trust Mode
By default, QoS is disabled on all Catalyst switches and must be explicitly enabled in global
configuration mode. The QoS configuration is the same for a multilayer or routed-access deployment.
The following sample QoS configuration must be enabled on all the access-layer switches deployed in
district office and school sites.
cr24-2960-DO(config)#mls qos
cr24-2960-DO#show mls qos
QoS is enabled
QoS ip packet dscp rewrite is enabled
Upon enabling QoS in the Catalyst switches, all physical ports are assigned untrusted mode. The network
administrator must explicitly enable the trust settings on the physical port where trusted or conditionally
trusted endpoints are connected. The Catalyst switches can trust the ingress packets based on 802.1P
(CoS-based), ToS (ip-prec-based) or DSCP (DSCP-based) values. Best practice is to deploy DSCP-based
trust mode on all the trusted and conditionally-trusted endpoints. This offers a higher level of
classification and marking granularity than other methods. The following sample DSCP-based trust
configuration must be enabled on the access-switch ports connecting to trusted or conditionally-trusted
endpoints.
Access (Multilayer or Routed-Access)
Trusted Port
cr24-2960-DO(config)#interface FastEthernet0/5
cr24-2960-DO(config-if)# description CONNECTED TO IPVS 2500 - CAMERA
cr24-2960-DO(config-if)# mls qos trust dscp
cr24-2960-DO#show mls qos interface f0/5
FastEthernet0/5
trust state: trust dscp
trust mode: trust dscp
trust enabled flag: ena
COS override: dis
default COS: 0
DSCP Mutation Map: Default DSCP Mutation Map
Trust device: none
qos mode: port-based
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Conditionally-Trusted Port
cr24-2960-DO(config)#interface FastEthernet0/3
cr24-2960-DO(config-if)# description CONNECTED TO PHONE
cr24-2960-DO(config-if)# mls qos trust device cisco-phone
cr24-2960-DO(config-if)# mls qos trust dscp
cr24-2960-DO#show mls qos interface f0/3
FastEthernet0/3
trust state: trust dscp
trust mode: trust dscp
trust enabled flag: ena
COS override: dis
default COS: 0
DSCP Mutation Map: Default DSCP Mutation Map
Trust device: cisco-phone
qos mode: port-based
UnTrusted Port
As described earlier, the default trust mode is untrusted when globally enabling QoS function. Without
explicit trust configuration on Fas0/1 port, the following show command verifies current trust state and
mode:
cr24-2960-DO#show mls qos interface f0/1
FastEthernet0/1
trust state: not trusted
trust mode: not trusted
trust enabled flag: ena
COS override: dis
default COS: 0
DSCP Mutation Map: Default DSCP Mutation Map
Trust device: none
qos mode: port-based
Implementing QoS Classification
When creating QoS classification policies, the network administrator needs to consider what
applications are present at the access edge (in the ingress direction) and whether these applications are
sourced from trusted or untrusted endpoints. If PC endpoints are secured and centrally administered,
then endpoint PCs may be considered trusted endpoints. In most deployments, this is not the case, thus
PCs are considered untrusted endpoints for the remainder of this document.
Not every application class, as defined in the Cisco-modified RFC 4594-based model, is present in the
ingress direction at the access edge; therefore, it is not necessary to provision the following application
classes at the access-layer:
•
Network Control—It is assumed that access-layer switch will not transmit or receive network control
traffic from endpoints; hence this class is not implemented.
•
Broadcast Video—Broadcast video and multimedia streaming server are centrally deployed at the
district office and multicast traffic is originated from trusted data center servers and is unidirectional
to school site endpoints (and should not be sourced from school endpoints).
•
Operation, Administration and Management—Primarily generated by network devices (routers,
switches) and collected by management stations which are typically deployed in the trusted data
center network, or a network control center.
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All applications present at the access edge need to be assigned a classification, as shown in Figure 34.
Voice traffic is primarily sourced from Cisco IP telephony devices residing in the voice VLAN
(VVLAN). These are trusted devices, or conditionally trusted, if users also attach PC's, etc to the same
port. Voice communication may also be sourced from PC's with soft-phone applications, like Cisco
Unified Personal Communicator (CUPC). Since such applications share the same UDP port range as
multimedia conferencing traffic (UDP/RTP ports 16384-32767) this soft-phone VoIP traffic is
indistinguishable, and should be classified with multimedia conferencing streams. See Figure 3-31.
QoS Classes
Application
PHB
Application Examples
Network Control
CS6
EIGRP, OSPF, HSRP, IKE
VoIP
EF
Cisco IP Phone
Present at Campus
Access-Edge (Ingress)?
Trust
Boundary
Yes
Trusted
Cisco IPVS, Enterprise TV
Broadcast Video
Realtime Interactive
CS4
Cisco TelePresence
Yes
Trusted
Multimedia Conferencing
AF4
Cisco CUPC, WebEx
Yes
Untrusted
Multimedia Streaming
AF3
Cisco DMS, IP/TV
Signaling
CS3
SCCP, SIP, H.323
Yes
Trusted
Transactional Data
AF2
ERP Apps, CRM Apps
Yes
Untrusted
OAM
CS2
SNMP, SSH, Syslog
Bulk Data
AF1
Email, FTP, Backup
Yes
Untrusted
Best Effort
DF
Default Class
Yes
Untrusted
Scavenger
CS1
YouTube, Gaming, P2P
Yes
Untrusted
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Figure 3-31
MQC offers scalability and flexibility in configuring QoS to classify all 8 application classes by using
match statements or an extended access-list to match the exact value or range of Layer-4 known ports
that each application uses to communicate on the network. The following sample configuration creates
an extended access-list for each application and then applies it under class-map configuration mode.
cr24-3560r-DO(config)#ip access-list extended MULTIMEDIA-CONFERENCING
cr24-3560r-DO(config-ext-nacl)# remark RTP
cr24-3560r-DO(config-ext-nacl)# permit udp any any range 16384 32767
cr24-3560r-DO(config-ext-nacl)#!
cr24-3560r-DO(config-ext-nacl)#ip access-list extended SIGNALING
cr24-3560r-DO(config-ext-nacl)# remark SCCP
cr24-3560r-DO(config-ext-nacl)# permit tcp any any range 2000 2002
cr24-3560r-DO(config-ext-nacl)# remark SIP
cr24-3560r-DO(config-ext-nacl)# permit tcp any any range 5060 5061
cr24-3560r-DO(config-ext-nacl)# permit udp any any range 5060 5061
cr24-3560r-DO(config-ext-nacl)#
cr24-3560r-DO(config-ext-nacl)#ip access-list extended TRANSACTIONAL-DATA
cr24-3560r-DO(config-ext-nacl)# remark HTTPS
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 443
cr24-3560r-DO(config-ext-nacl)# remark ORACLE-SQL*NET
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 1521
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cr24-3560r-DO(config-ext-nacl)# permit udp any any eq 1521
cr24-3560r-DO(config-ext-nacl)# remark ORACLE
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 1526
cr24-3560r-DO(config-ext-nacl)# permit udp any any eq 1526
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 1575
cr24-3560r-DO(config-ext-nacl)# permit udp any any eq 1575
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 1630
cr24-3560r-DO(config-ext-nacl)#
cr24-3560r-DO(config-ext-nacl)#ip access-list extended BULK-DATA
cr24-3560r-DO(config-ext-nacl)# remark FTP
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq ftp
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq ftp-data
cr24-3560r-DO(config-ext-nacl)# remark SSH/SFTP
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 22
cr24-3560r-DO(config-ext-nacl)# remark SMTP/SECURE SMTP
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq smtp
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 465
cr24-3560r-DO(config-ext-nacl)# remark IMAP/SECURE IMAP
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 143
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 993
cr24-3560r-DO(config-ext-nacl)# remark POP3/SECURE POP3
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq pop3
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 995
cr24-3560r-DO(config-ext-nacl)# remark CONNECTED PC BACKUP
cr24-3560r-DO(config-ext-nacl)# permit tcp any eq 1914 any
cr24-3560r-DO(config-ext-nacl)#
cr24-3560r-DO(config-ext-nacl)#ip access-list extended DEFAULT
cr24-3560r-DO(config-ext-nacl)# remark EXPLICIT CLASS-DEFAULT
cr24-3560r-DO(config-ext-nacl)# permit ip any any
cr24-3560r-DO(config-ext-nacl)#
cr24-3560r-DO(config-ext-nacl)#ip access-list extended SCAVENGER
cr24-3560r-DO(config-ext-nacl)# remark KAZAA
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 1214
cr24-3560r-DO(config-ext-nacl)# permit udp any any eq 1214
cr24-3560r-DO(config-ext-nacl)# remark MICROSOFT DIRECT X GAMING
cr24-3560r-DO(config-ext-nacl)# permit tcp any any range 2300 2400
cr24-3560r-DO(config-ext-nacl)# permit udp any any range 2300 2400
cr24-3560r-DO(config-ext-nacl)# remark APPLE ITUNES MUSIC SHARING
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 3689
cr24-3560r-DO(config-ext-nacl)# permit udp any any eq 3689
cr24-3560r-DO(config-ext-nacl)# remark BITTORRENT
cr24-3560r-DO(config-ext-nacl)# permit tcp any any range 6881 6999
cr24-3560r-DO(config-ext-nacl)# remark YAHOO GAMES
cr24-3560r-DO(config-ext-nacl)# permit tcp any any eq 11999
cr24-3560r-DO(config-ext-nacl)# remark MSN GAMING ZONE
cr24-3560r-DO(config-ext-nacl)# permit tcp any any range 28800 29100
cr24-3560r-DO(config-ext-nacl)#
Creating class-map for each application services and applying match statement:
cr24-3560r-DO(config)#class-map match-all VVLAN-SIGNALING
cr24-3560r-DO(config-cmap)# match ip dscp cs3
cr24-3560r-DO(config-cmap)#
cr24-3560r-DO(config-cmap)#class-map match-all VVLAN-VOIP
cr24-3560r-DO(config-cmap)# match ip dscp ef
cr24-3560r-DO(config-cmap)#
cr24-3560r-DO(config-cmap)#class-map match-all MULTIMEDIA-CONFERENCING
cr24-3560r-DO(config-cmap)# match access-group name MULTIMEDIA-CONFERENCING
cr24-3560r-DO(config-cmap)#
cr24-3560r-DO(config-cmap)#class-map match-all SIGNALING
cr24-3560r-DO(config-cmap)# match access-group name SIGNALING
cr24-3560r-DO(config-cmap)#
cr24-3560r-DO(config-cmap)#class-map match-all TRANSACTIONAL-DATA
cr24-3560r-DO(config-cmap)# match access-group name TRANSACTIONAL-DATA
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cr24-3560r-DO(config-cmap)#
cr24-3560r-DO(config-cmap)#class-map match-all
cr24-3560r-DO(config-cmap)# match access-group
cr24-3560r-DO(config-cmap)#
cr24-3560r-DO(config-cmap)#class-map match-all
cr24-3560r-DO(config-cmap)# match access-group
cr24-3560r-DO(config-cmap)#
cr24-3560r-DO(config-cmap)#class-map match-all
cr24-3560r-DO(config-cmap)# match access-group
BULK-DATA
name BULK-DATA
DEFAULT
name DEFAULT
SCAVENGER
name SCAVENGER
Implementing Ingress Policer
It is important to limit how much bandwidth each class may use at the ingress to the access-layer for two
primary reasons:
•
Bandwidth Bottleneck—To prevent network congestion, each physical port at trust boundary must
be rate-limited. The rate-limit value may differ based on several factors—end-to-end network
bandwidth capacity, end-station, and application performance capacities, etc.
•
Bandwidth Security—Well-known applications like Cisco IP telephony, use a fixed amount of
bandwidth per device, based on codec. It is important to police high-priority application traffic
which is assigned to the high-priority queue, otherwise it could consume too much overall network
bandwidth and impact other application performance.
In addition to policing, the rate-limit function also provides the ability to take different actions on the
excess incoming traffic which exceeds the established limits. The exceed-action for each class must be
carefully designed based on the nature of application to provide best effort service based on network
bandwidth availability. Table 3-9 provides best practice policing guidelines for different classes to be
implemented for trusted and conditional-trusted endpoints at the network edge.
Table 3-9
Best Practice Policing Guidelines
Application
Policing Rate
Conform-Action
Exceed-Action
VoIP Signaling
<32 kbps
Pass
Drop
VoIP Bearer
<128 kbps
Pass
Drop
Pass
Drop
1
Multimedia Conferencing
<5Mbps
Signaling
<32 kbps
Transactional Data
Bulk Data
Best Effort
Scavenger
1.
Pass
Drop
<10 Mbps
1
Pass
Remark to CS1
<10 Mbps
1
Pass
Remark to CS1
<10 Mbps
1
Pass
Remark to CS1
<10 Mbps
1
Pass
Drop
Rate varies based on several factors as defined earlier. This table depicts sample rate-limiting values.
As described in the “QoS in Catalyst Fixed Configuration Switches” section on page 3-50, the policer
capabilities differ in Cisco Catalyst switching platforms. When deploying policer policies on the
access-layer switches the following platform limitations must be taken into consideration:
•
The Catalyst 2960 and 2975 can only police to a minimum rate of 1 Mbps; all other platforms within
this switch-product family can police to a minimum rate of 8 kbps.
•
Only the Cisco Catalyst 3650-E and 3750-E support policing on 10 Gigabit Ethernet interfaces.
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The following sample configuration shows how to deploy policing for multiple classes on trusted and
conditionally-trusted ingress ports in access-layer switches.
Trusted or Conditionally-Trusted Port
cr24-3560r-DO(config)#policy-map Phone+PC-Policy
cr24-3560r-DO(config-pmap)# class VVLAN-VOIP
cr24-3560r-DO(config-pmap-c)# police 128000 8000 exceed-action drop
cr24-3560r-DO(config-pmap-c)# class VVLAN-SIGNALING
cr24-3560r-DO(config-pmap-c)# police 32000 8000 exceed-action drop
cr24-3560r-DO(config-pmap-c)# class MULTIMEDIA-CONFERENCING
cr24-3560r-DO(config-pmap-c)# police 5000000 8000 exceed-action drop
cr24-3560r-DO(config-pmap-c)# class SIGNALING
cr24-3560r-DO(config-pmap-c)# police 32000 8000 exceed-action drop
cr24-3560r-DO(config-pmap-c)# class TRANSACTIONAL-DATA
cr24-3560r-DO(config-pmap-c)# police 10000000 8000 exceed-action policed-dscp-transmit
cr24-3560r-DO(config-pmap-c)# class BULK-DATA
cr24-3560r-DO(config-pmap-c)# police 10000000 8000 exceed-action policed-dscp-transmit
cr24-3560r-DO(config-pmap-c)# class SCAVENGER
cr24-3560r-DO(config-pmap-c)# police 10000000 8000 exceed-action drop
cr24-3560r-DO(config-pmap-c)# class DEFAULT
cr24-3560r-DO(config-pmap-c)# police 10000000 8000 exceed-action policed-dscp-transmit
All ingress traffic (default class) from untrusted endpoint be must be policed without explicit
classification that requires differentiated services. The following sample configuration shows how to
deploy policing on untrusted ingress ports in access-layer switches:
UnTrusted Port
cr24-3560r-DO(config)#policy-map UnTrusted-PC-Policy
cr24-3560r-DO(config-pmap)# class class-default
cr24-3560r-DO(config-pmap-c)# police 10000000 8000 exceed-action drop
Implementing Ingress Marking
Accurate DSCP marking of ingress traffic at the access-layer switch is critical to ensure proper QoS
service treatment as traffic traverses through the network. All classified and policed traffic must be
explicitly marked using the policy-map configuration based on an 8-class QoS model as shown in
Figure 3-31.
Best practice is to use a explicit marking command (set dscp) even for trusted application classes (like
VVLAN-VOIP and VVLAN-SIGNALING), rather than a trust policy-map action. A trust statement in a
policy map requires multiple hardware entries, while the use of an explicit (seemingly redundant)
marking command, improves the hardware efficiency.
The following sample configuration shows how to implement explicit marking for multiple classes on
trusted and conditionally-trusted ingress ports in access-layer switches:
Trusted or Conditionally-Trusted Port
cr24-3560r-DO(config)#policy-map Phone+PC-Policy
cr24-3560r-DO(config-pmap)# class VVLAN-VOIP
cr24-3560r-DO(config-pmap-c)# set dscp ef
cr24-3560r-DO(config-pmap-c)# class VVLAN-SIGNALING
cr24-3560r-DO(config-pmap-c)# set dscp cs3
cr24-3560r-DO(config-pmap-c)# class MULTIMEDIA-CONFERENCING
cr24-3560r-DO(config-pmap-c)# set dscp af41
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cr24-3560r-DO(config-pmap-c)#
cr24-3560r-DO(config-pmap-c)#
cr24-3560r-DO(config-pmap-c)#
cr24-3560r-DO(config-pmap-c)#
cr24-3560r-DO(config-pmap-c)#
cr24-3560r-DO(config-pmap-c)#
cr24-3560r-DO(config-pmap-c)#
cr24-3560r-DO(config-pmap-c)#
cr24-3560r-DO(config-pmap-c)#
cr24-3560r-DO(config-pmap-c)#
class SIGNALING
set dscp cs3
class TRANSACTIONAL-DATA
set dscp af21
class BULK-DATA
set dscp af11
class SCAVENGER
set dscp cs1
class DEFAULT
set dscp default
All ingress traffic (default class) from an untrusted endpoint must be marked without a explicit
classification. The following sample configuration shows how to implement explicit DSCP marking:
Untrusted Port
cr24-3560r-DO(config)#policy-map UnTrusted-PC-Policy
cr24-3560r-DO(config-pmap)# class class-default
cr24-3560r-DO(config-pmap-c)# set dscp default
Applying Ingress Policies
After creating a complete policy-map with all the QoS policies defined, the service-policy must be
applied on the edge interface of the access-layer to enforce the QoS configuration. Cisco Catalyst
switches offer three simplified methods to apply service-policies. Depending on the deployment model,
any of these methods may be used:
Figure 3-32
•
Port-based QoS—Applying service-policy on a per physical port basis will force traffic to
pass-through the QoS policies before entering the network. Port-based QoS functions on a
per-physical port basis even if the port is associated with a logical VLAN.
•
VLAN-based QoS—Applying service-policy on per VLAN basis requires the policy-map to be
attached to a logical Layer-3 SVI interface. Every physical port associated with the VLAN will
require an extra configuration to enforce the QoS policies defined on a logical interface.
•
Per-Port/Per-VLAN-based QoS—Not supported on all the Catalyst platforms and the configuration
commands are platform-specific. Per-port/per-VLAN-based QoS creates a nested hierarchical
policy-map that operates on a trunk interface. A different policy-map can be applied on each logical
SVI interface that is associated to a single physical port.
Depicts All Three QoS Implementation Method
Port-Based QoS
VLAN-Based QoS
VLAN Interface
VLAN Interface
VLAN 10
VLAN 20
VLAN 10
Per-Port/ Per-VLAN Based QoS
VLAN 20
VLAN Interface
VVLAN 10
VVLAN 20
DVLAN 100
DVLAN 200
Physical port attached
with single service-policy
Single Logical port attached
with single service-policy
Multiple Logical ports attached
with different service-policy
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Physical Ports
The following sample configuration shows how to deploy port-based QoS on the access-layer switches:
cr24-3560r-DO(config)#interface fastethernet0/4
cr24-3560r-DO(config-if)# description CONNECTED TO PHONE+PC
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cr24-3560r-DO(config-if)# service-policy input Phone+PC-Policy
cr24-3560r-DO#show policy-map interface f0/4 | inc Service|Class
Service-policy input: Phone+PC-Policy
Class-map: VVLAN-VOIP (match-all)
Class-map: VVLAN-SIGNALING (match-all)
Class-map: MULTIMEDIA-CONFERENCING (match-all)
Class-map: SIGNALING (match-all)
Class-map: TRANSACTIONAL-DATA (match-all)
Class-map: BULK-DATA (match-all)
Class-map: SCAVENGER (match-all)
Class-map: DEFAULT (match-all)
Class-map: class-default (match-any)
Applying Ingress Queueing
Fixed configuration Cisco Catalyst switches (29xx and 3xxx) not only offer differentiated services on
the network ports but also internally on the switching fabric. After enabling QoS and attaching inbound
policies on the physical ports, all the packets that meet the specified policy are forwarded to the
switching fabric for egress switching. The aggregate bandwidth from all edge ports may exceed
switching fabric bandwidth and cause internal congestion.
These platforms support two internal ingress queues: normal queue and priority queue. The ingress
queue inspects the DSCP value on each incoming frame and assigns it to either the normal or priority
queue. High priority traffic, like DSCP EF marked packets, are placed in the priority queue and switched
before processing the normal queue.
The Catalyst 3750-E family of switches supports the weighted tail drop (WTD) congestion avoidance
mechanism. WTD is implemented on queues to manage the queue length. WTD drops packets from the
queue, based on dscp value, and the associated threshold. If the threshold is exceeded for a given internal
DSCP value, the switch drops the packet. Each queue has three threshold values. The internal DSCP
determines which of the three threshold values is applied to the frame. Two of the three thresholds are
configurable (explicit) and one is not (implicit). This last threshold corresponds to the tail of the queue
(100 percent limit).
Figure 3-33 depicts how different class-of-service applications are mapped to the Ingress Queue
structure (1P1Q3T) and how each queue is assigned a different WTD threshold.
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Ingress Queueing
Ingress Queue
1P1Q3T
Application
PHB
Network Control
CS7
EF
Internetwork Control
CS6
CS5
VoIP
EF
CS4
Broadcast Video
CS5
CS7
Realtime Interactive
CS4
CS6
Multimedia Conferencing
AF4
CS3
Multimedia Streaming
AF3
AF4
Signaling
CS3
AF3
Transactional Data
AF2
AF2
OAM
CS2
CS2
Bulk Data
AF1
AF1
Best Effort
DF
DF
Scavenger
CS1
CS1
Queue 2
Priority-Queue
Q1T3
Q1T2
Q1T1
Queue 1
Normal Queue
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Figure 3-33
The DSCP marked packets in the policy-map must be assigned to the appropriate queue and each queue
must be configured with the recommended WTD threshold as defined in Figure 3-33. The following
ingress queue configuration must be enabled in global configuration mode on every access-layer switch.
cr25-3750-DO(config)#mls qos srr-queue input priority-queue 2 bandwidth 30
! Q2 is enabled as a strict-priority ingress queue with 30% BW
cr25-3750-DO(config)#mls qos srr-queue input bandwidth 70 30
! Q1 is assigned 70% BW via SRR shared weights
! Q1 SRR shared weight is ignored (as it has been configured as a PQ)
cr25-3750-DO(config)#mls qos srr-queue input threshold 1 80 90
! Q1 thresholds are configured at 80% (Q1T1) and 90% (Q1T2)
! Q1T3 is implicitly set at 100% (the tail of the queue)
! Q2 thresholds are all set (by default) to 100% (the tail of Q2)
! This section configures ingress DSCP-to-Queue Mappings
cr25-3750-DO(config)# mls qos srr-queue input dscp-map queue 1 threshold 1 0 8 10 12 14
! DSCP DF, CS1 and AF1 are mapped to ingress Q1T1
cr25-3750-DO(config)# mls qos srr-queue input dscp-map queue 1 threshold 1 16 18 20 22
! DSCP CS2 and AF2 are mapped to ingress Q1T1
cr25-3750-DO(config)# mls qos srr-queue input dscp-map queue 1 threshold 1 26 28 30 34 36
38
! DSCP AF3 and AF4 are mapped to ingress Q1T1
cr25-3750-DO(config)#mls qos srr-queue input dscp-map queue 1 threshold 2 24
! DSCP CS3 is mapped to ingress Q1T2
cr25-3750-DO(config)#mls qos srr-queue input dscp-map queue 1 threshold 3 48 56
! DSCP CS6 and CS7 are mapped to ingress Q1T3 (the tail of Q1)
cr25-3750-DO(config)#mls qos srr-queue input dscp-map queue 2 threshold 3 32 40 46
! DSCP CS4, CS5 and EF are mapped to ingress Q2T3 (the tail of the PQ)
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cr25-3750-DO#show mls qos input-queue
Queue:
12
----------------------------------buffers
:9010
bandwidth :7030
priority :030
threshold1:80100
threshold2:90100
cr25-3750-DO#show mls qos maps dscp-input-q
Dscp-inputq-threshold map:
d1 :d2
0
1
2
3
8
9
4
5
6
7
---------------------------------------------------------------------------------------0 :
01-01 01-01 01-01 01-01 01-01 01-01 01-01 01-01 01-01 01-01
1 :
01-01 01-01 01-01 01-01 01-01 01-01 01-01 01-01 01-01 01-01
2 :
01-01 01-01 01-01 01-01 01-02 01-01 01-01 01-01 01-01 01-01
3 :
01-01 01-01 02-03 01-01 01-01 01-01 01-01 01-01 01-01 01-01
4 :
02-03 02-01 02-01 02-01 02-01 02-01 02-03 02-01 01-03 01-01
5 :
01-01 01-01 01-01 01-01 01-01 01-01 01-03 01-01 01-01 01-01
6 :
01-01 01-01 01-01 01-01
Deploying Egress QoS
The QoS implementation for egress traffic toward the network edge on access-layer switches is much
simpler than the ingress traffic QoS. The egress QoS implementation provides optimal queueing policies
for each class and sets the drop thresholds to prevent network congestion and application performance
impact. Cisco Catalyst switches support 4 hardware queues that are assigned the following policies:
•
Real-time queue (to support a RFC 3246 EF PHB service)
•
Guaranteed bandwidth queue (to support RFC 2597 AF PHB services)
•
Default queue (to support a RFC 2474 DF service)
•
Bandwidth constrained queue (to support a RFC 3662 scavenger service)
As a best practice each physical or logical link must diversify bandwidth assignment to map with
hardware queues:
•
Real-time queue should not exceed 33% of the link's bandwidth.
•
Default queue should be at least 25% of the link's bandwidth.
•
Bulk/scavenger queue should not exceed 5% of the link's bandwidth.
Figure 3-34 shows best practice egress queue bandwidth allocation for each class.
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Figure 3-34
Engress QoS
5%
33%
25%
Real-Time
Guaranteed
Best-Effort
37%
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Scavenger/Bulk
Given these minimum queuing requirements and bandwidth allocation recommendations, the following
application classes can be mapped to the respective queues:
•
Realtime Queue—Voice, broadcast video, and realtime interactive may be mapped to the realtime
queue (per RFC 4594).
•
Guaranteed Queue—Network/internetwork control, signaling, network management, multimedia
conferencing, multimedia streaming, and transactional data can be mapped to the guaranteed
bandwidth queue. Congestion avoidance mechanisms (i.e., selective dropping tools), such as
WRED, can be enabled on this class. If configurable drop thresholds are supported on the platform,
these may be enabled to provide intra-queue QoS to these application classes, in the respective order
they are listed (such that control plane protocols receive the highest level of QoS within a given
queue).
•
Scavenger/Bulk Queue—Bulk data and scavenger traffic can be mapped to the
bandwidth-constrained queue and congestion avoidance mechanisms can be enabled on this class.
If configurable drop thresholds are supported on the platform, these may be enabled to provide
inter-queue QoS to drop scavenger traffic ahead of bulk data.
•
Default Queue—Best effort traffic can be mapped to the default queue; congestion avoidance
mechanisms can be enabled on this class.
The egress queueing is designed to map traffic, based on DSCP value, to four egress queues. as shown
above. The egress QoS model for a platform that supports DSCP-to-queue mapping with a 1P3Q8T
queuing structure is depicted in Figure 3-35.
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Access-Layer 1P3Q3T Egress Queue Model
Egress Queue
1P3Q3T
Application
PHB
Network Control
CS7
Internetwork Control
CS6
VoIP
EF
Broadcast Video
CS5
CS7
Realtime Interactive
CS4
CS6
Queue
Multimedia Conferencing
AF4
CS3
2
Multimedia Streaming
AF3
CS2
Signaling
CS3
Transactional Data
AF2
OAM
CS2
Bulk Data
AF1
Best Effort
DF
Scavenger
CS1
CS1
AF1
DF
Queue 4
(5%)
Q4T2
Q4T1
Queue 3
(55%)
Q2T3
Q2T2
Q2T1
(30%)
AF4
AF3
AF2
EF
Queue 1
CS5 Priority-Queue
(30%)
CS4
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Figure 3-35
DSCP marked packets are assigned to the appropriate queue and each queue is configured with
appropriate WTD threshold as defined in Figure 3-35. Egress queueing is the same on network edge port
as well as on uplink connected to internal network, and it is independent of trust mode. The following
egress queue configuration in global configuration mode, must be enabled on every access-layer switch
in the network.
! This section configures explicit WTD thresholds on Q2 and Q4
cr25-3750-DO(config)#mls qos queue-set output 1 threshold 2 80 90 100 100
! Q2T1 is set to 80%; Q2T2 is set to 90%
cr25-3750-DO(config)#mls qos queue-set output 1 threshold 4 60 100 100 100
! Q4T1 is set to 60%; all other thresholds for Q4 remain at 100%
! This section configures egress DSCP-to-Queue mappings
cr25-3750-DO(config)# mls qos srr-queue output dscp-map queue 1 threshold 3 32 40 46
! DSCP CS4, CS5 and EF are mapped to egress Q1T3 (tail of the PQ)
cr25-3750-DO(config)# mls qos srr-queue output dscp-map queue 2 threshold 1 16 18 20 22
! DSCP CS2 and AF2 are mapped to egress Q2T1
cr25-3750-DO(config)# mls qos srr-queue output dscp-map queue 2 threshold 1 26 28 30 34 36
38
! DSCP AF3 and AF4 are mapped to egress Q2T1
cr25-3750-DO(config)#mls qos srr-queue output dscp-map queue 2 threshold 2 24
! DSCP CS3 is mapped to egress Q2T2
cr25-3750-DO(config)#mls qos srr-queue output dscp-map queue 2 threshold 3 48 56
! DSCP CS6 and CS7 are mapped to egress Q2T3
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cr25-3750-DO(config)#mls qos srr-queue output dscp-map queue 3 threshold 3 0
! DSCP DF is mapped to egress Q3T3 (tail of the best effort queue)
cr25-3750-DO(config)#mls qos srr-queue output dscp-map queue 4 threshold 1 8
! DSCP CS1 is mapped to egress Q4T1
cr25-3750-DO(config)# mls qos srr-queue output dscp-map queue 4 threshold 2 10 12 14
! DSCP AF1 is mapped to Q4T2 (tail of the less-than-best-effort queue)
! This section configures interface egress queuing parameters
cr25-3750-DO(config)#interface range GigabitEthernet1/0/1-48
cr25-3750-DO(config-if-range)# queue-set 1
! The interface(s) is assigned to queue-set 1
cr25-3750-DO(config-if-range)# srr-queue bandwidth share 1 30 35 5
! The SRR sharing weights are set to allocate 30% BW to Q2
! 35% BW to Q3 and 5% BW to Q4
! Q1 SRR sharing weight is ignored, as it will be configured as a PQ
cr25-3750-DO(config-if-range)# priority-queue out
! Q1 is enabled as a strict priority queue
cr25-3750-DO#show mls qos interface GigabitEthernet1/0/27 queueing
GigabitEthernet1/0/27
Egress Priority Queue : enabled
Shaped queue weights (absolute) : 25 0 0 0
Shared queue weights : 1 30 35 5
The port bandwidth limit : 100 (Operational Bandwidth:100.0)
The port is mapped to qset : 1
Table 3-10 and Table 3-11 summarize the ingress and egress QoS policies at the access-layer for several
types of validated endpoints.
Table 3-10
Summarized Network Edge Ingress QoS Deployment Guidelines
Trust
Model
End-Point
DSCP Trust
Classification
Marking
Policing
Ingress
Queueing
Unmanaged devices,
printers etc
UnTrusted
Don’t Trust.
Default.
None
None
Yes
Yes
Managed secured
devices, Servers etc
Trusted
Trust
8 Class
Yes
Yes
Yes
Phone
Trusted
Trust
Yes
Yes
Yes
Yes
Phone + Mobile PC
Conditionally-Tru Trust
sted
Yes
Yes
Yes
Yes
IP Video surveillance
Camera
Trusted
Trust
No
No
No
Yes
Digital Media Player
Trusted
Trust
No
No
No
Yes
Core facing Uplinks
Trusted
Trust
No
No
No
Yes
Table 3-11
Model
Summarized Network Edge Egress QoS Deployment Guidelines
End-Point
Unmanaged devices, printers
etc
Trust
Model
Classification / Marking /
Policing
Egress
Queueing
Bandwidth
Share
UnTrusted
None
Yes
Yes
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Table 3-11
Summarized Network Edge Egress QoS Deployment Guidelines (continued)
Managed secured devices,
Servers etc
Trusted
None
Yes
Yes
Phone
Trusted
None
Yes
Yes
Phone + Mobile PC
Conditionally-Truste None
d
Yes
Yes
IP Video surveillance Camera
Trusted
None
Yes
Yes
Digital Media Player
Trusted
None
Yes
Yes
Core facing Uplinks
Trusted
None
Yes
Yes
Deploying Network Core QoS
All connections between internal network devices that are deployed within the network domain
boundary are classified as trusted devices and follow the same QoS best practices recommended in the
previous section. Ingress and egress core QoS policies are simpler than those applied at the network
edge, See Figure 3-36.
Figure 3-36
School Network Core QoS Boundary
Distribution/Core
Ingress QoS Ploicy
Egress QoS Ploicy
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Access
The core network devices are considered trusted and rely on the access-switch to properly mark DSCP
values. The core network is deployed to ensure consistent differentiated QoS service across the network.
This ensures there is no service quality degradation for high-priority traffic, such as IP telephony or
video.
The QoS implementation at the District Office and Larger School Site differ from the Smaller School
Site, due to different platforms used as the collapsed core router (Catalyst 4500 vs Catalyst 3750
StackWise).
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Deploying District Office or Large School Site Ingress QoS
The district office collapsed core is deployed with Cisco Catalyst 4500 with Supervisor-6E, whereas the
Larger School Site collapsed core is deployed with Cisco Catalyst 4500 with either Supervisor-6E or
Supervisor-V. The Supervisor-6E product has a redesigned QoS implementation which matches Cisco
IOS routers. No ingress QoS configuration is required, since QoS is enabled by default, and all ports are
considered trusted.
The Cisco Catalyst 4500 with Supervisor-V requires ingress QoS configuration similar to trusted
endpoints in the access-layer. Following is a sample configuration which enables QoS in the Catalyst
4500 with Supervisor-V:
cr35-4507-SS1(config)#qos
! Enables QoS function in the switch
cr35-4507-SS1#show qos
QoS is enabled globally
IP header DSCP rewrite is enabled
After QoS is globally enabled, all interfaces are in the untrusted mode by default. QoS trust settings must
be set on each Layer 2 or Layer 3 port that is physically connected to another device within the network
trust boundary. When Cisco Catalyst 4500 is deployed in EtherChannel mode, the QoS trust settings
must be applied to every physical member-link and logical port-channel interface. Best practice is to
enable trust DSCP settings on each physical and logical interface that connects to another internal trusted
device (e.g., access-layer switches in wiring closet or data-center, a router, wireless LAN controller
(WLC)).
cr35-4507-SS1(config)#interface range Po11 , Gi1/2 , Gi2/2
cr35-4507-SS1(config-if-range)#description Connected to cr35-2960-SS1
cr35-4507-SS1(config-if-range)#qos trust dscp
cr35-4507-SS1#show qos interface Port-channel 11
QoS is enabled globally
Port QoS is enabled
Administrative Port Trust State: 'dscp'
Operational Port Trust State: 'dscp'
Trust device: none
Default DSCP: 0 Default CoS: 0
Additional ingress QoS techniques (such as classification, marking, and policing) are not required at the
collapsed core layer since these functions are already performed by the access-layer switches. The
architecture of Catalyst 4500 with classic or next-generation Supervisor do not need ingress queueing
since all of the forwarding decisions are made centrally on the supervisor. There are no additional QoS
configurations required at the collapsed core-layer system.
Deploying Small School Site Ingress QoS
The Smaller School Site is deployed using Cisco Catalyst 3750-E StackWise as the collapsed core
switch. The QoS implementation remains the same whether deployed as 3750-E StackWise or as a
standalone switch. By default, QoS is disabled on the 3750-E switch. Following is a sample
configuration to enable QoS in global configuration mode:
cr36-3750s-SS100(config)#mls qos
! Enables QoS function in the switch
cr36-3750s-SS100#show mls qos
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QoS is enabled
QoS ip packet dscp rewrite is enabled
After QoS is globally enabled, all interfaces are in the untrusted mode by default. QoS trust settings must
be set on each Layer 2 or Layer 3 port that is physically connected to another device within the network
trust boundary. When Cisco Catalyst 3750-E StackWise Plus is deployed in EtherChannel mode, the QoS
trust settings must be applied to every physical member-link. Best practice is to enable trust DSCP
settings on each physical and logical interface that connects to another internal trusted device (e.g.,
access-layer switches in wiring closet or data-center, a router, wireless LAN controller (WLC)).
cr36-3750s-SS100(config)#int range gi1/0/49 , gi3/0/49
cr36-3750s-SS100(config-if-range)# description Connected to cr36-2960-SS100
cr36-3750s-SS100(config-if-range)#mls qos trust dscp
cr36-3750s-SS100#show mls qos interface Gi1/0/49
GigabitEthernet1/0/49
trust state: trust dscp
trust mode: trust dscp
trust enabled flag: ena
COS override: dis
default COS: 0
DSCP Mutation Map: Default DSCP Mutation Map
Trust device: none
qos mode: port-based
Additional ingress QoS techniques (such as classification, marking, and policing) are not required at the
collapsed core layer since these functions are already performed by the access-layer switches. The
ingress queueing and DSCP-Ingress-Queue function in 3750-E StackWise Plus must be enabled to allow
differentiation between normal versus high-priority traffic. The ingress queuing configuration is
consistent with the implementation at the access-edge. Following is a sample configuration for the
ingress queues of the Catalyst 3750-E StackWise collapsed core switch:
cr36-3750-SS100(config)#mls qos srr-queue input priority-queue 2 bandwidth 30
! Q2 is enabled as a strict-priority ingress queue with 30% BW
cr36-3750-SS100(config)#mls qos srr-queue input bandwidth 70 30
! Q1 is assigned 70% BW via SRR shared weights
! Q1 SRR shared weight is ignored (as it has been configured as a PQ)
cr36-3750-SS100(config)#mls qos srr-queue input threshold 1 80 90
! Q1 thresholds are configured at 80% (Q1T1) and 90% (Q1T2)
! Q1T3 is implicitly set at 100% (the tail of the queue)
! Q2 thresholds are all set (by default) to 100% (the tail of Q2)
! This section configures ingress DSCP-to-Queue Mappings
cr36-3750-SS100(config)# mls qos srr-queue input dscp-map queue 1 threshold 1 0 8 10 12 14
! DSCP DF, CS1 and AF1 are mapped to ingress Q1T1
cr36-3750-SS100(config)# mls qos srr-queue input dscp-map queue 1 threshold 1 16 18 20 22
! DSCP CS2 and AF2 are mapped to ingress Q1T1
cr36-3750-SS100(config)# mls qos srr-queue input dscp-map queue 1 threshold 1 26 28 30 34
36 38
! DSCP AF3 and AF4 are mapped to ingress Q1T1
cr36-3750-SS100(config)#mls qos srr-queue input dscp-map queue 1 threshold 2 24
! DSCP CS3 is mapped to ingress Q1T2
cr36-3750-SS100(config)# mls qos srr-queue input dscp-map queue 1 threshold 3 48 56
! DSCP CS6 and CS7 are mapped to ingress Q1T3 (the tail of Q1)
cr36-3750-SS100(config)# mls qos srr-queue input dscp-map queue 2 threshold 3 32 40 46
! DSCP CS4, CS5 and EF are mapped to ingress Q2T3 (the tail of the PQ)
cr36-3750s-SS100#show mls qos input-queue
Queue
:
1
2
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------------------------------------buffers
:
90
10
bandwidth :
70
30
priority :
0
30
threshold1:
80
100
threshold2:
90
100
cr36-3750s-SS100#show mls qos maps dscp-input-q
Dscp-inputq-threshold map:
d1 :d2
0
1
2
3
8
9
4
5
6
7
---------------------------------------------------------------------------------------0
1
2
3
4
5
6
:
:
:
:
:
:
:
01-01
01-01
01-01
01-01
02-03
01-01
01-01
01-01
01-01
01-01
01-01
02-01
01-01
01-01
01-01
01-01
01-01
02-03
02-01
01-01
01-01
01-01
01-01
01-01
01-01
02-01
01-01
01-01
01-01
01-01
01-02
01-01
02-01
01-01
01-01
01-01
01-01
01-01
02-01
01-01
01-01
01-01
01-01
01-01
02-03
01-03
01-01
01-01
01-01
01-01
02-01
01-01
01-01
01-01
01-01
01-01
01-03
01-01
01-01
01-01
01-01
01-01
01-01
01-01
Deploying District Office Egress QoS
The district office is deployed with Cisco Catalyst 4500 with Supervisor-6E as the collapsed core router.
Egress QoS from the collapsed core router provides optimized queueing and drop thresholds to drop
excess low-priority traffic and protect high-priority traffic.
The Supervisor-6E supports up to 8 traffic classes for QoS mapping. It also supports a platform-specific
congestion avoidance algorithm to provide Active Queue Management (AQM) with Dynamic Buffer
Limiting (DBL). DBL tracks the queue length for each traffic flow in the switch. When the queue length
of a flow exceeds its limit, DBL drops packets or sets the Explicit Congestion Notification (ECN) bit in
the TCP packet header. With 8 egress (1P7Q1T) queues and DBL capability in the Sup-6E, the
bandwidth distribution for each class changes, as shown in Figure 3-37.
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District Office School Network
Egress Queue
1P7Q1T (+DBL)
Application
PHB
Network Control
CS7
EF
Internetwork Control
CS6
CS5
VoIP
EF
CS4
Broadcast Video
CS5
Realtime Interactive
CS4
Multimedia Conferencing
AF4
Multimedia Streaming
AF3
Signaling
CS3
Transactional Data
AF2
OAM
CS2
Bulk Data
AF1
Best Effort
Scavenger
Priority-Queue
(30%)
CS7 & CS6
Q7 (10%)
CS3 & CS2
AF4
Q6 (10%)
AF3
Q5 (10%)
AF2
Q4 (10%)
AF1
Q3 (4%)
DF
DF
Q2 (1%)
CS1
CS1
Q1 (25%)
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Figure 3-37
Implementing QoS policies on Sup-6E-based Catalyst 4500 platform follows IOS (MQC)-model. The
egress QoS implementation bundles the queueing and policing functions on EtherChannel based
networks. To provide low-latency for high priority traffic, all lower priority traffic must wait until the
priority-queue is empty. Best practice includes implementing a policer along with the priority-queue to
provide more fair treatment for all traffic.
The following sample configuration shows how to create an 8-class egress queueing model and protect
from high-priority traffic consuming more bandwidth than global policies allow. The egress QoS
service-policy must be applied to all the physical EtherChannel member-links connected to different
service-blocks (i.e., WAN edge, data center, access-layer switches, etc).
! Creating class-map for each classes using match dscp statement as marked by edge systems
cr24-4507-DO(config)#class-map match-all PRIORITY-QUEUE
cr24-4507-DO(config-cmap)# match dscp ef
cr24-4507-DO(config-cmap)# match dscp cs5
cr24-4507-DO(config-cmap)# match dscp cs4
cr24-4507-DO(config-cmap)#class-map match-all CONTROL-MGMT-QUEUE
cr24-4507-DO(config-cmap)# match dscp cs7
cr24-4507-DO(config-cmap)# match dscp cs6
cr24-4507-DO(config-cmap)# match dscp cs3
cr24-4507-DO(config-cmap)# match dscp cs2
cr24-4507-DO(config-cmap)#class-map match-all MULTIMEDIA-CONFERENCING-QUEUE
cr24-4507-DO(config-cmap)# match dscp af41 af42 af43
cr24-4507-DO(config-cmap)#class-map match-all MULTIMEDIA-STREAMING-QUEUE
cr24-4507-DO(config-cmap)# match dscp af31 af32 af33
cr24-4507-DO(config-cmap)#class-map match-all TRANSACTIONAL-DATA-QUEUE
cr24-4507-DO(config-cmap)# match dscp af21 af22 af23
cr24-4507-DO(config-cmap)#class-map match-all BULK-DATA-QUEUE
cr24-4507-DO(config-cmap)# match dscp af11 af12 af13
cr24-4507-DO(config-cmap)#class-map match-all SCAVENGER-QUEUE
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cr24-4507-DO(config-cmap)# match
dscp cs1
! Creating policy-map and configure queueing for class-of-service
cr24-4507-DO(config)#policy-map EGRESS-POLICY
cr24-4507-DO(config-pmap)# class PRIORITY-QUEUE
cr24-4507-DO(config-pmap-c)#
priority
cr24-4507-DO(config-pmap-c)# class CONTROL-MGMT-QUEUE
cr24-4507-DO(config-pmap-c)#
bandwidth remaining percent 10
cr24-4507-DO(config-pmap-c)# class MULTIMEDIA-CONFERENCING-QUEUE
cr24-4507-DO(config-pmap-c)#
bandwidth remaining percent 10
cr24-4507-DO(config-pmap-c)# class MULTIMEDIA-STREAMING-QUEUE
cr24-4507-DO(config-pmap-c)#
bandwidth remaining percent 10
cr24-4507-DO(config-pmap-c)# class TRANSACTIONAL-DATA-QUEUE
cr24-4507-DO(config-pmap-c)#
bandwidth remaining percent 10
cr24-4507-DO(config-pmap-c)#
dbl
cr24-4507-DO(config-pmap-c)# class BULK-DATA-QUEUE
cr24-4507-DO(config-pmap-c)#
bandwidth remaining percent 4
cr24-4507-DO(config-pmap-c)#
dbl
cr24-4507-DO(config-pmap-c)# class SCAVENGER-QUEUE
cr24-4507-DO(config-pmap-c)#
bandwidth remaining percent 1
cr24-4507-DO(config-pmap-c)# class class-default
cr24-4507-DO(config-pmap-c)#
bandwidth remaining percent 25
cr24-4507-DO(config-pmap-c)#
dbl
! Attaching egress service-policy on all physical member-link ports
cr24-4507-DO(config)#int range Gi1/1 - 6 , Gi2/1 - 6
cr24-4507-DO(config-if-range)# service-policy output EGRESS-POLICY
EtherChannel is an aggregated logical bundle interface that does not perform queueing and relies on
individual member-links to queue egress traffic. The policer to rate-limit priority class traffic must be
implemented on EtherChannel and not on individual member-links since it governs the aggregate egress
traffic limits. The following additional policy-map must be created to classify priority-queue class traffic
and rate-limit the traffic to 30% of egress link capacity:
cr24-4507-DO(config)#class-map match-any PRIORITY-QUEUE
cr24-4507-DO(config-cmap)# match dscp ef
cr24-4507-DO(config-cmap)# match dscp cs5
cr24-4507-DO(config-cmap)# match dscp cs4
cr24-4507-DO(config)#policy-map PQ-POLICER
cr24-4507-DO(config-pmap)# class PRIORITY-QUEUE
cr24-4507-DO(config-pmap-c)# police cir 300 m conform-action transmit exceed-action drop
cr24-4507-DO(config)#interface range Port-Channel 1 , Port-channel 11 - 17
cr24-4507-DO(config-if-range)#service-policy output PQ-POLICER
Deploying Large School Site Egress QoS
The large school site is deployed with Cisco Catalyst 4500 and either Supervisor-6E or Supervisor-V as
the collapsed core router. If the larger school site network is deployed with Sup-6E, then the
configuration is the same as described in the previous section.
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The QoS deployment and implementation guidelines differ when the Cisco Catalyst 4500 is deployed
with the classic Supervisor-V module. The SupV supervisor can have up to four egress queues like the
Cisco Catalyst 29xx and 35xx/37xx Series switches. Before forwarding egress traffic, each packet must
be internally classified and placed in the appropriate egress-queue. Placing traffic into different
class-of-service queues, will offer traffic prioritization and guaranteed bandwidth to the network. The
following sample configuration shows how to implement egress QoS on the Catalyst 4500 with
Supervisor-V:
cr35-4507-SS1(config)#qos dbl
! DBL is globally enabled
cr35-4507-SS1(config)#no qos dbl dscp-based 32
cr35-4507-SS1(config)#no qos dbl dscp-based 40
cr35-4507-SS1(config)#no qos dbl dscp-based 46
! DBL is explicitly disabled on DSCP CS4, CS5 and EF
! as these DSCP values are assigned to the PQ
! and as such should never experience congestion avoidance drops
cr35-4507-SS1(config)#qos dbl exceed-action ecn
! DBL will mark IP ECN bits in the event of congestion
! This section configures the DBL policy-map
cr35-4507-SS1(config)#policy-map DBL
cr35-4507-SS1(config-pmap)# class class-default
cr35-4507-SS1(config-pmap-c)# dbl
! DBL is enabled on all flows
! (with the exception of DSCP CS4, CS5 and EF)
! This section configures the DSCP-to-Queue mappings
cr35-4507-SS1(config)#qos map dscp 8 10 12 14 to tx-queue 1
! DSCP CS1 and AF1 are mapped to Q1 (the less than best effort queue)
cr35-4507-SS1(config)#qos map dscp 0 to tx-queue 2
! DSCP DF is mapped to Q2 (the best effort/default queue)
cr35-4507-SS1(config)#qos map dscp 32 40 46 to tx-queue 3
! DSCP CS4, CS5 and EF are mapped to Q3 (the PQ)
cr35-4507-SS1(config)#qos map dscp 16 18 20 22 to tx-queue 4
! DSCP CS2 and AF2 are mapped to Q4 (guaranteed BW queue)
cr35-4507-SS1(config)#qos map dscp 24 26 28 30 to tx-queue 4
! DSCP CS3 and AF3 are mapped to Q4 (guaranteed BW queue)
cr35-4507-SS1(config)#qos map dscp 34 36 38 to tx-queue 4
! DSCP AF4 is mapped to Q4 (guaranteed BW queue)
cr35-4507-SS1(config)#qos map dscp 48 56 to tx-queue 4
! DSCP CS6 and CS7 are mapped to Q4 (guaranteed BW queue)
! This section configures all the EtherChannel member-link for egress queuing
cr35-4507-SS1(config)#interface range Gig1/1 - 6 , Gig2/1 - 6
cr35-4507-SS1(config-if-range)# tx-queue 1
cr35-4507-SS1(config-if-tx-queue)# bandwidth percent 5
! Q1 (less than best effort queue) is assigned 5% BW
cr35-4507-SS1(config-if-tx-queue)# tx-queue 2
cr35-4507-SS1(config-if-tx-queue)# bandwidth percent 35
! Q2 (default/best effort queue) is assigned 35% BW
cr35-4507-SS1(config-if-tx-queue)# tx-queue 3
cr35-4507-SS1(config-if-tx-queue)# priority high
cr35-4507-SS1(config-if-tx-queue)# bandwidth percent 30
! Q3 is enabled as a PQ and assigned 30% BW
cr35-4507-SS1(config-if-tx-queue)# tx-queue 4
cr35-4507-SS1(config-if-tx-queue)# bandwidth percent 30
! Q4 (guaranteed BW queue) is assigned 30% BW
cr35-4507-SS1(config-if-range)# service-policy output DBL
! DBL policy-map is attached to the interface(s)
cr35-4507-SS1#show qos dbl
QOS is enabled globally
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DBL is enabled globally on DSCP values:
0-31,33-39,41-45,47-63
DBL flow includes vlan
DBL flow includes layer4-ports
DBL uses ecn to indicate congestion
DBL exceed-action probability: 15%
DBL max credits: 15
DBL aggressive credit limit: 10
DBL aggressive buffer limit: 2 packets
cr35-4507-SS1#show qos maps dscp tx-queue
DSCP-TxQueue Mapping Table (dscp = d1d2)
d1 : d2 0
1
2
3
4
5
6
7
8
9
-----------------------------------------------0 :
02 01 01 01 01 01 01 01 01 01
1 :
01 01 01 01 01 01 04 02 04 02
2 :
04 02 04 02 04 02 04 02 04 02
3 :
04 02 03 03 04 03 04 03 04 03
4 :
03 03 03 03 03 03 03 03 04 04
5 :
04 04 04 04 04 04 04 04 04 04
6 :
04 04 04 04
cr35-4507-SS1#show qos interface Gig1/2
QoS is enabled globally
Port QoS is enabled
Administrative Port Trust State: 'dscp'
Operational Port Trust State: 'dscp'
Trust device: none
Default DSCP: 0 Default CoS: 0
Appliance trust: none
Tx-Queue
Bandwidth
ShapeRate
Priority
(bps)
(bps)
1
50000000
disabled
N/A
2
350000000
disabled
N/A2080
3
300000000disabled
high2080
4
300000000disabledN/A2080
QueueSize
(packets)
2080
Deploying Small School Site Egress QoS
Collapsed Core – Catalyst 3750-E StackWise Plus
The small school site is deployed with Cisco Catalyst 3750-E StackWise as the collapsed core router.
The Catalyst 3750-E can have up to four egress queues. Before forwarding egress traffic, each packet is
placed in the appropriate egress-queue as shown in Figure 3-35. The Catalyst 3750-E switch supports
Shaped Round Robin (SRR) packet schedule service which can be deployed in two different modes:
•
Shaped—To provide guaranteed bandwidth, the shaped egress queue reserves some of the
bandwidth of the port for each queue. Traffic load exceeding the shape parameter gets dropped. The
queue cannot take advantage of excess bandwidth capacity when other queues are not using their
bandwidth allocations.
•
Shared—Shared mode also provides guaranteed bandwidth for each queue; however, it allows the
flexibility of using excess bandwidth when there is any available.
The following sample configuration shows how to implement egress QoS on the Catalyst 3750-E:
! This section configures explicit WTD thresholds on Q2 and Q4
cr36-3750s-SS100(config)#mls qos queue-set output 1 threshold 2 80 90 100 100
! Q2T1 is set to 80%; Q2T2 is set to 90%
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cr36-3750s-SS100(config)#mls qos queue-set output 1 threshold 4 60 100 100 100
! Q4T1 is set to 60%; all other thresholds for Q4 remain at 100%
! This section configures egress DSCP-to-Queue mappings
cr36-3750s-SS100(config)# mls qos srr-queue output dscp-map queue 1 threshold 3 32 40 46
! DSCP CS4, CS5 and EF are mapped to egress Q1T3 (tail of the PQ)
cr36-3750s-SS100(config)# mls qos srr-queue output dscp-map queue 2 threshold 1 16 18 20
22
! DSCP CS2 and AF2 are mapped to egress Q2T1
cr36-3750s-SS100(config)#mls qos srr-queue output dscp-map queue 2 threshold 1 26 28 30 34
36 38
! DSCP AF3 and AF4 are mapped to egress Q2T1
cr36-3750s-SS100(config)#mls qos srr-queue output dscp-map queue 2 threshold 2 24
! DSCP CS3 is mapped to egress Q2T2
cr36-3750s-SS100(config)#mls qos srr-queue output dscp-map queue 2 threshold 3 48 56
! DSCP CS6 and CS7 are mapped to egress Q2T3
cr36-3750s-SS100(config)#mls qos srr-queue output dscp-map queue 3 threshold 3 0
! DSCP DF is mapped to egress Q3T3 (tail of the best effort queue)
cr36-3750s-SS100(config)#mls qos srr-queue output dscp-map queue 4 threshold 1 8
! DSCP CS1 is mapped to egress Q4T1
cr36-3750s-SS100(config)# mls qos srr-queue output dscp-map queue 4 threshold 2 10 12 14
! DSCP AF1 is mapped to Q4T2 (tail of the less-than-best-effort queue)
! This section configures interface egress queuing parameters
cr36-3750s-SS100(config)#interface range GigabitEthernet1/0/1-48
cr36-3750s-SS100(config-if-range)# queue-set 1
! The interface(s) is assigned to queue-set 1
cr36-3750s-SS100(config-if-range)# srr-queue bandwidth share 1 30 35 5
! The SRR sharing weights are set to allocate 30% BW to Q2
! 35% BW to Q3 and 5% BW to Q4
! Q1 SRR sharing weight is ignored, as it will be configured as a PQ
cr36-3750s-SS100(config-if-range)# priority-queue out
! Q1 is enabled as a strict priority queue
cr36-3750s-SS100#show mls qos interface GigabitEthernet1/0/49 queueing
GigabitEthernet1/0/49
Egress Priority Queue : enabled
Shaped queue weights (absolute) : 25 0 0 0
Shared queue weights : 1 30 35 5
The port bandwidth limit : 100 (Operational Bandwidth:100.0)
The port is mapped to qset : 1
Building a Resilient Network
The Schools Service Ready Architecture is a high performance, resilient and scalable network design.
A network outage may be caused by the system, human error, or natural disaster. The Schools SRA is
designed to minimize the impact of a failure regardless of the cause. Network outages may be either
planned or unplanned.
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•
Planned Outage—Planned network outage occurs when a portion of the network is taken out of
service as part of a scheduled event (e.g., a software upgrade).
•
Unplanned Outage—Any unscheduled network outage is considered an unplanned outage. Such
outages may be caused by internal faults in the network, or devices due to hardware or software
malfunctions.
The network is designed to recover from most un planned outages in less than a second (milliseconds).
In many situations, the user will not even notice the outage occurred. If the outage lasts longer (several
seconds), then the user will notice the lack of application responsiveness. The network is designed to
minimize the overall impact of a unplanned network outage, and gracefully adjust and recover from
many outage conditions. Figure 3-38 shows an example of a real-time VoIP application and user impact
depending on duration of outage event.
Figure 3-38
VoIP User Impact for Minor and Major Network Outage
50
45
40
35
30
25
20
Data Lose (Seconds)
15
10
5
No Impact
Minimal Impact
to Voice
User Hangs Up
Phone Reset*
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Several techniques are used to make the network design more resilient. Deploying redundant devices and
redundant connections between devices, enables the network to recover from fault conditions.
Identifying critical versus non critical applications, and network resources optimizes cost performance,
by focusing on the most important elements of the network design. The resiliency of a system design is
often categorized as follows:
•
Network Resiliency—Provides redundancy during physical link outages (e.g., fiber cut, bad
transceivers, incorrect cabling, etc).
•
Device Resiliency—Protects network during device outage triggered by hardware or software (e.g.
software crash, non-responsive supervisor, etc).
•
Operational Resiliency—Capabilities which provide network availability even during planned
network outage conditions - (e.g., ISSU features which enable software upgrades while device is
operating).
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Figure 3-39
Resiliency Deployment Strategy
Network Resiliency
Device Resiliency
Distribution/Core
Network Resiliency
Device Resiliency
Operational Resiliency
Data
Center
Network Resiliency
Device Resiliency
Network Resiliency
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Access
The high availability framework is based upon the three resiliency categories described in the previous
section. Figure 3-40 shows which technologies are implemented to achieve each category of resiliency.
Figure 3-40
High-Availability Categories and Technologies
Resilient
Goal
Resilient
Strategies
Network Service Availability
Network
Resiliency
Device
Resiliency
Operational
Resiliency
EtherChannel
NSF/SSO
UDLD
ISSU
Stack Wise
IP Event Dampening
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Resilient
Technologies
Redundant Hardware Components
Redundant hardware implementations vary between fixed configuration and modular Cisco Catalyst
switches. Selective deployment of redundant hardware is an important element of the Schools SRA
design which delivers device resiliency.
Redundant hardware component for device resiliency varies between fixed configuration and modular
Cisco Catalyst switches. To protect against common network faults or resets, all critical district office
and school campus network devices must be deployed with similar device resiliency configuration. This
subsection provides a basic redundant hardware deployment guideline at the access-layer and collapsed
core switching platforms in the campus network.
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Redundant Power System
Redundant power supplies protect the device from power outage or power supply failure. Protecting the
power is not only important for the network device, but also the endpoints that rely on power delivery
over the Ethernet network. Redundant power supplies are deployed differently depending on the switch
type:
•
Modular Switch—Dual power supplies can be deployed in the modular switching platforms like the
Cisco Catalyst 4500-E. By default, the Cisco Catalyst 4500 power supply operates in 1+1 redundant
mode (both power supplies are active).
•
Fixed configuration switch—Fixed configuration switches are deployed with internal power
supplies and they may also use Cisco RPS 2300 external power supply. A single Cisco RPS 2300
power supply has modular power supplies and fans to deliver power to multiple switches. Deploying
internal and external power-supplies provides a redundant power solution for fixed configuration
switches.
Redundant Network Connectivity
Redundant network connections protect the system from failure due to cable or transceiver faults.
Redundant network connections attached to a single fixed configuration switch or network module in the
Cisco Catalyst 4500 switch do not protect against internal device hardware or software fault.
Best practice design is to deploy redundant network modules within the Catalyst 4500 switch and the
Cisco 3750-E StackWise Plus solution in the small school site collapsed core network. Deploying the
3750-E StackWise Plus in critical access-layer switches in the data center network and in the district
office is also best practice. Connecting redundant paths to different hardware elements provides both
network and device resiliency.
Figure 3-41
Redundant Network Connectivity
Redundant StackWise Plus Switch
Stack Ring
Distribution/Core
Distribution/Core
Redundant
Line Cards
Diversed
Fiber Paths
Diversed
Fiber Paths
Redundant
Switch
Redundant
Switch
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Access
Access
Redundant Control-Plane
The processing software operation is different in standalone or StackWise fixed configuration switches,
and on a supervisor module of a modular switch. Network communication and forwarding operations
can be disrupted when the processing unit fails, causing a network outage. Network recovery techniques
vary based on the different platforms.
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The standalone and non-stackable fixed configuration switches like the Cisco Catalyst 2960 or 3560-E
feature power redundancy and network resiliency support; however they do not protect against a
processing unit failure. During a processing unit failure event, all endpoints attached to the switch are
impacted and network recovery time is undeterministic.
Device resiliency in Cisco StackWise and modular switching platforms provides 1+1 redundancy with
enterprise-class high availability and deterministic network recovery time.
Cisco StackWise
Cisco Catalyst 2975 and Catalyst 3750-E switches can be deployed in StackWise mode using a special
stack cable. Up to nine switches can be integrated into a single stack that delivers distributed forwarding
architecture and unified single control and management plane. Device level redundancy in StackWise
mode is achieved via stacking multiple switches using the Cisco StackWise technology. One switch from
the stack is selected automatically to serve as the master, which manages the centralized control-plane
process. Cisco StackWise solution provides 1:N redundancy. In the event of a active master-switch
outage, a new master is selected automatically. See Figure 3-42.
Figure 3-42
Cisco Stack Wise Switching Architecture
Member
Switch – 1
Master
Switch – 2
Member
Switch – 3
Single Logical Switch
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Stack Ring
Since Cisco StackWise enables up to 9 switches to appear as one logical switch, it has centralized
management and control functions. Most Layer 2 and Layer 3 functions are centrally performed,
however Layer-2 topology development is distributed (i.e., each switch performs the function
independently). Table 3-12 lists network protocol functions and identifies which are centralized and
which are distributed.
Table 3-12
Cisco StackWise Centralized and Distributed Control-Plane
Protocols
Layer 2 Protocols
Layer 3 Protocols
Function
MAC Table
Distributed
Spanning-Tree Protocol
Distributed
CDP
Centralized
VLAN Database
Centralized
EtherChannel - LACP
Centralized
Layer 3 Management
Centralized
Layer 3 Routing
Centralized
Cisco StackWise solution offers network and device resiliency with distributed forwarding. In the event
of a master switch outage, Non-Stop Forwarding (NSF) enables packet forwarding to continue based on
current state information, while a new master switch is selected. New master switch selection is
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accomplished in the range of 700 to 1000 milliseconds; the amount of time to reestablish the
control-plane and develop distributed forwarding will vary depending on the size and complexity of the
network.
Following is a best practice to reduce Layer-3 disruption in the event of a master switch outage:
Determine the master switch with the higher switch priority, and isolate the uplink Layer-3 EtherChannel
bundle path by using physical ports from member switches (i.e. don't use the master switches ports for
Etherchannel uplinks). With NSF capabilities enabled, this design decreases network downtime during
a master-switch outage.
An understanding of SSO and StackWise components and failover events associated with NSF provides
significant insight in designing a network that enables supervisor redundancy. The following subsection
uses the above concepts and principles to identify the design parameters, and applies them to develop a
best-practice hierarchical network with the highest availability.
Cisco Modular Switch
The Cisco Catalyst 4500 modular switch supports redundant supervisors, and Stateful Switch Over
(SSO). When deployed along with NSF, the 4500 provides a enterprise-class highly available system
with network and device resiliency.
SSO is a Cisco IOS service used to synchronize critical forwarding and protocol state information
between redundant supervisors configured in a single chassis. With SSO enabled, one supervisor in the
system assumes the role of active and the other supervisor becomes the hot-standby. Each is ready to
backup the other, thus providing 1:1 hot redundancy to protect from a control-plane outage. Since both
supervisors are active, the system benefits by using the physical ports from both supervisors during
normal operation. SSO synchronizes system services such as DHCP snooping, Switched Port Analyzer
(SPAN), security access control lists (ACLs), and QoS policies so ensure the switch provides the same
level of protection and service after a supervisor failover event.
NSF enables packets to continue to be forwarded using existing routing table information, during
switchover. NSF also provides graceful restart to the routing protocol such that during the failover, the
routing protocol remains aware of the change and does not react by resetting its adjacency. If the routing
protocol were to react to the failure event, and alter routing path information, the effectiveness of stateful
switch over would be diminished.
Operational Resiliency Strategy
Designing the network to recover from unplanned outages is important. It is also important to consider
how to minimize the disruption caused by planned outages. These planned outages can be due to standard
operational processes, configuration changes, software and hardware upgrades, etc.
The same redundant components which mitigate the impact of unplanned outages can also be used to
minimize the disruption caused by planned outages. The ability to upgrade individual devices without
taking them out of service is enabled by having internal component redundancy (such as with power
supplies, and supervisors) complemented with the system software capabilities. Two primary
mechanisms exist to upgrade software in a live network:
•
Full-image In-Service Software Upgrade (ISSU) on the Cisco Catalyst 4500 leverages dual
supervisors to allow for a full, in-place Cisco IOS upgrade. This leverages the NSF/SSO capabilities
of the switch and provides for less than 200 msec of traffic loss during a full Cisco IOS upgrade.
•
Network and device level redundancy, along with the necessary software control mechanisms,
guarantee controlled and fast recovery of all data flows following a fault condition, and provide the
ability to manage the fault tolerant infrastructure during planned outage events.
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Validating operational resiliency is beyond the scope of this design guide, refer to CCO documentation
for deployment guidelines.
Deploying High Availability in School Network
Many of the design features of the Schools Service Ready Architecture which were described in
“Deploying Schools Foundation Services” section on page 3-15, contribute to the network high
availability capabilities. This section focuses on how to implement additional features which complete
the Schools SRA high availability design.
Network Resiliency
Etherchannel and UDLD are two design features which are included in the network foundation services,
which contribute to network resiliency.
Implementing IP Event Dampening
Poor signaling or a loose connection may cause continuous port-flap (port alternates between active state
and inactive state). A single interface flapping can impact the stability and availability of the network.
Route summarization is one technique which mitigates the impact of a flapping port. Summarization
isolates the fault domain with a new metric announcement by the aggregator and thereby hides the local
networks fault within the domain.
A best practice to mitigate local network domain instability due to port-flap, is implementing IP Event
Dampening on all layer 3 interfaces. Each time the Layer-3 interface flaps the IP dampening tracks and
records the flap event. Upon multiple flaps, a logical penalty is assigned to the port and suppresses link
status notification to IP routing until the port becomes stable. IP event dampening is a local function and
does not have a signaling mechanism to communicate with a remote system. It can be implemented on
each individual physical or logical Layer-3 interface: physical ports, SVI or port-channels. Following is
a example configuration to implement IP Event Damenping:
Distribution/Core
cr24-4507-DO(config)#int range Port1 , Gig5/6 , Gig6/6 , Vlan 101 - 110
cr24-4507-DO(config-if-range)#dampening
cr24-4507-DO#show interface dampening | be Port
Port-channel1 Connected to cr24-3750ME-DO
Flaps Penalty
Supp ReuseTm
HalfL ReuseV
SuppV
0
0
FALSE
0
5
1000
16000
0
MaxSTm
2000
MaxP Restart
20
The following output illustrates how the IP event dampening keeps track of port flaps and makes a
decision to notify IP routing process based on interface suppression status:
cr24-4507-DO#debug dampening interface
cr24-4507-DO#show logging | inc EvD|IF-EvD
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12:32:03.274: EvD(GigabitEthernet5/6): charge penalty 1000, new accum. penalty 1000, flap
count 2
12:32:03.274: EvD(GigabitEthernet5/6): accum. penalty 1000, not suppressed
12:32:03.274: IF-EvD(GigabitEthernet5/6): update IP Routing state to DOWN, interface is
not suppressed
cr24-4507-DO#show interface dampening | be 5/6
Flaps Penalty
Supp ReuseTm
HalfL ReuseV
SuppV
2
0
FALSE
0
5
1000
0
MaxSTm
2000
MaxP Restart
20
16000
In a multilayer access-distribution design, the Layer-2 and Layer-3 demarcation is at the collapsed
core-distribution device. IP event dampening is enabled on per-logical VLAN (SVI) interface basis on
the collapsed core device. IP event dampening becomes more effective when each access-layer switch is
deployed with a unique set of Layer-2 VLANs.
Assigning unique VLANs on each access-layer switch also helps IP event dampening to isolate the
problem and prevent network faults triggered in a multilayer network. The following output illustrates
how IP event dampening keeps track of individual logical VLAN networks associated to same Layer-2
physical trunk ports. When a Layer-2 trunk port flaps, the state of SVI also flaps, and forces dampening
to track and penalize unstable interfaces:
12:58:41.332: EvD(Vlan101): charge penalty 1000, new accum. penalty 2627, flap count 3
12:58:41.332: EvD(Vlan101): accum. penalty 2627, now suppressed with a reuse intervals of
7
12:58:41.332: IF-EvD(Vlan101): update IP Routing state to DOWN, interface is suppressed
cr24-4507-DO#show interface dampening
Vlan101 Connected to cr24_2960_Dept_1_VLAN
Flaps Penalty
Supp ReuseTm
HalfL ReuseV
SuppV MaxSTm
MaxP Restart
3
71
FALSE
0
5
1000
2000
20
16000
0
Device Resiliency
As described earlier, redundant hardware is an important technique for achieving device resiliency. The
Schools SRA network design applies hardware redundancy considering the cost / performance tradeoffs.
Implementing Redundant Power Supply
Redundant power supplies can prevent a system outage due to power outage, power supply or fan
hardware failure. All Cisco Catalyst switching platforms supports robust 1+1 redundant power
capabilities that can be deployed with internal or external power source management. See Figure 3-43.
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Figure 3-43
Cisco Catalyst Internal and External Power Redundancy Option
Redundant Dual
Power Supply
Cisco 2300 RPS
Redundant
Internal
Power Supply
Redundant
External
Power Supply
Master
Member
Catalyst 4500
Member
Catalyst 3750-E
227579
RPS Cable
Catalyst 4500—Redundant Internal Power Supply
The Cisco Catalyst 4500 provides power to internal hardware components and external devices like IP
phones. All the power is provided by the internal power supply. Dual-power supplies in the Catalyst 4500
can operate in one of two different modes:
•
Redundant Mode—By default, Catalyst 4500 power supply operates in redundant mode offering 1+1
redundant option. The system determines power capacity and number of power supplies required
based on the power required for all internal and external power components. Both power supplies
must have sufficient power to support all the installed modules and operate in 1+1 redundant mode.
cr24-4507-DO(config)#power redundancy-mode redundant
cr24-4507-DO#show power supplies
Power supplies needed by system
:1
Power supplies currently available :2
•
Combined Mode—If the system power requirement exceeds the capacity of a single power supply,
then both power supplies can be combined to increase the capacity. In this mode, the power system
does not provide 1+1 power redundancy. The following global configuration will enable power
supplies to operate in combined mode:
cr24-4507-DO(config)#power redundancy-mode combined
cr24-4507-DO#show power supplies
Power supplies needed by system:2
Power supplies currently available:2
Catalyst 29xx and 3xxx – Redundant External Power Supply with RPS
Cisco Redundant Power Supply (RPS) 2300 provides up to 6 RPS ports to provide backup power to
critical access-layer switches in the school network. Additional power resiliency can be added by
deploying dual-power supply to backup to two devices simultaneously. The Cisco RPS 2300 can be
provisioned through the Cisco 3750-E or 3560-E Series switches using the enable mode CLI:
cr36-3750s-ss100#power rps <switch id> name CiscoRPS
cr36-3750s-ss100#power rps <switch id> port <rps port id> active
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cr36-3750s-ss100#show env rps
SW StatusRPS NameRPS Serial# RPS Port#HN'
---- -------- ------------ -------------------- 璋
1
ActiveCiscoRPSFDO1246SG3L1` 2
ActiveCiscoRPSFDO1246SG3L3
3
ActiveCiscoRPSFDO1246SG3L5
RPS Name: CiscoRPS
State: Activexs
PID: PWR-RPS2300
Serial#: FDO1246SG3L
Fan: Good
Temperature: Green
RPS Power Supply A: Present
PID
: C3K-PWR-1150WAC
Serial#
: DTM124000XX
System Power : Good
PoE Power: Good
Watts
: 300/800 (System/PoE)
Redundant RPS
RPS Power Supply B: PresentPower Supply
PID
: C3K-PWR-1150WAC
Serial#
: DTM124000WW
System Power: Good
PoE Power
: Good
Watts
: 300/800 (System/PoE)
DCOut State
Connected Priority BackingUp WillBackup Portname
SW#
-------- -------------------- --------- -------------- ------------------------------1 Active Yes
6
NoYes
cr36-3750s-SS100
1
2 Active Yes
6
NoYes
<>
<>
3 Active Yes
6
NoYes
cr36-3750s_SS100
2
4 Active Yes
6
NoYes
<>
<>
5 Active Yes
6
NoYes
cr36-3750s_SS100
3
6 Active Yes
6
NoYes
<>
<>
Implementing Redundant Control Plane System
The collapsed core device in the district office and school sites (Catalyst 4500 or 3750-E StackWise) is
deployed with redundant supervisor, or StackWise Plus to enable graceful recovery from switch
hardware outage. Any access-switch which is deemed critical may be deployed as StackWise Plus to
improve device resiliency. The implementation for each switch is different, and is discussed separately
in the sections which follow.
Resilient Cisco StackWise
Cisco Catalyst 2975 supports StackWise, and is used when a resilient layer-2 access switch is required.
Cisco Catalyst 3750-E supports StackWise, and is used when a resilient layer 2 or layer 3 access switch
is required. Cisco 3750-E StackWise Plus is deployed for the collapsed core in the small school site
network.
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StackWise switch provisioning is done dynamically by the StackWise protocol. Cisco IOS automatically
adjusts the interface addressing and its associated configuration based on the number of provisioned
switches in the stack.
cr26-2975-DO#show run | inc provision
switch 1 provision ws-c2975gs-48ps-l
switch 2 provision ws-c2975gs-48ps-l
switch 3 provision ws-c2975gs-48ps-l
Master Switch Election
The centralized control-plane and management plane is managed by the master switch in the stack. By
default, the master switch selection within the ring is performed dynamically by negotiating several
parameters and capabilities between each switch within the stack. Each StackWise-capable switch is by
default configured with priority 1.
cr26-3750r-DO#show switch
Switch/Stack Mac Address : 0023.eb7b.e580
H/W
Current
Switch# Role
Mac AddressPriority
Version
State
----------------------------------------------------------------------------------------* 1 Member0023.eb7b.e580
1
0
Ready
2Master 0026.5284.ec80
1
0
Ready
3Member0025.eb7b.e680
1
0
Ready
As described in previous section, the Cisco StackWise architecture is not SSO-capable. This means all
the centralized Layer-3 functions must be reestablished with the neighbor switch during a master-switch
outage. To minimize the control-plane impact and improve network convergence the Layer 3 up links
should be diverse, originating from member switches, instead of the master switch. The default switch
priority must be increased manually after identifying the master switch and switch number. The new
switch priority becomes effective after switch reset.
cr26-3750r-DO(config)#switch 2 priority 15
Changing the Switch Priority of Switch Number 2 to 15
cr26-3750r-DO#show switch
Switch/Stack Mac Address : 0026.5284.ec80
H/W
Current
Switch# Role
Mac AddressPriority
Version
State
----------------------------------------------------------------------------------------1Member0023.eb7b.e580
1
0
Ready
* 2 Master 0026.5284.ec80
15
0
Ready
3Member0025.eb7b.e680
1
0
Ready
StackWise Layer 3 MAC Management
To provide a single unified logical network view in the network, the MAC addresses of Layer-3
interfaces on the StackWise (physical, logical, SVIs, port channel) are derived from the Ethernet MAC
address pool of the master switch in the stack. All the Layer-3 communication from the StackWise
switch to the endpoints (like IP phone, PC, servers and core network system) is based on the MAC
address pool of the master switch.
cr26-3750r-DO#show switch
Switch/Stack Mac Address : 0026.5284.ec80
H/W
Current
Switch# Role
Mac AddressPriority
Version
State
----------------------------------------------------------------------------------------1Member0023.eb7b.e580
1
0
Ready
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* 2 Master 0026.5284.ec80
3Member0025.eb7b.e680
cr26-3750r-DO#show version
. . .
Base ethernet MAC Address
. . .
15
0
0
1
Ready
Ready
: 00:26:52:84:EC:80
After a master-switch outage, the new master switch in the stack assigns new MAC addresses to all
Layer-3 interfaces, from the local MAC address pool. Once the new MAC address is assigned, it will
force the switch to generate a gratuitous ARP in the network to make sure no other system is using the
same MAC address. The default timer to retain the MAC address from the failed master switch is four
minutes. While the new MAC address is not assigned on Layer-3 interface and not being propagated and
updated in the network, the traffic will blackhole in the network.
cr26-3750r-DO#reload slot 2
Proceed with reload? [confirm]
Switch 2 reloading...
cr26-3750r-DO#show switch
Switch/Stack Mac Address : 0023.eb7b.e580
H/W
Current
Switch# Role
Mac AddressPriority
Version
State
----------------------------------------------------------------------------------------* 1 Master 0023.eb7b.e580
1
1
Ready
2Member000.0000.0000
0
1
Removed
3Member0025.eb7b.e680
1
1
Ready
To prevent this network instability, the old MAC address assignments on Layer-3 interfaces can be
retained even after the master switch fails. The new active master switch can continue to use the MAC
addresses assigned by the old master switch, which prevents ARP and routing outages in the network.
The default stack-mac timer settings must be changed in Cisco Catalyst 2975 and 3750-E StackWise
switch mode using the global configuration CLI mode as shown below:
cr26-3750r-DO(config)#stack-mac persistent timer 0
cr26-3750r-DO#show switch
Switch/Stack Mac Address : 0026.5284.ec80
Mac persistency wait time: Indefinite
H/W
Current
Switch# Role
Mac AddressPriority
Version
State
----------------------------------------------------------------------------------------1Member0023.eb7b.e580
1
0
Ready
* 2 Master 0026.5284.ec80
15
0
Ready
3Member0025.eb7b.e680
1
0
Ready
Non-Stop Forwarding (NSF)
The Cisco Catalyst 3750-E switch in StackWise mode is not SSO-capable. When the master switch fails,
the new master switch is required to reform the Layer-3 adjacencies with the neighbors in the network.
The forwarding architecture in StackWise switch is designed to provide non-stop forwarding during the
master switch outage using NSF technology. Each 3750-E switch in the stack maintains distributed
Layer-3 FIB from the old master switch and continues to forward upstream traffic, until they are updated
by the new master in the stack ring.
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To enable NSF capability, explicit configuration must be enabled under the routing process. NSF-aware
feature is enabled by default on all Layer-3 Ethernet switches to function in helper mode to perform
graceful recovery during NSF-capable Cisco 3750-E master switch outage. NSF-capable system can also
operate in NSF aware role:
NSF Capable Layer-3 Switch
cr36-3750s-SS100(config)#router eigrp 100
cr36-3750s-SS100(config-router)#nsf
cr36-3750s-SS100#show ip protocols | inc NSF
*** IP Routing is NSF aware ***
EIGRP NSF-aware route hold timer is 240
EIGRP NSF enabled
NSF signal timer is 20s
NSF converge timer is 120s
NSF-Aware Layer-3 Switch
cr24-3560r-DO#show ip protocols | inc NSF
*** IP Routing is NSF aware ***
EIGRP NSF-aware route hold timer is 240
NSF Timers
As depicted in the above show commands, the default NSF-aware system hold timer is 240 seconds.
Lowering the timer value may abruptly terminate graceful recovery, causing network instability. Best
practice is to use the default NSF hold timer, unless it is observed that NSF recovery takes longer than
240 seconds.
600 seconds after a graceful-recovery starts on a NSF-aware system, NSF clears the route stale marking
and resumes using the synchronized routing database.
! NSF Aware received graceful-restart message from new master switch
11:56:15.365: %DUAL-5-NBRCHANGE: EIGRP-IPv4:(100) 100: Neighbor 10.125.32.3
(Port-channel15) is resync: peer graceful-restart
11:56:15.365: EIGRP: NSF: AS100, NSF or GR initiated by 10.125.32.3 at 00:00:00, flags 0x4
! NSF route hold timer expires and searches and removes all stale route entries
received graceful-restart message from new master switch
12:00:15.392: EIGRP: NSF: AS100. route hold timer expiry
12:00:15.392: DUAL: Search for outdated routes from 10.125.32.3
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Resilient Cisco Catalyst 4500
A modular switching platform like the Cisco Catalyst 4500 is fully NSF/SSO-capable, providing 1+1
control plane redundancy. In the Catalyst 4500, all the intelligent Layer-2 and Layer-3 functions are
performed centrally on the supervisor module. Deploying redundant supervisor in SSO mode in same
system will allow the primary supervisor to fully synchronize the adjacencies, forwarding,
configuration, counters, and more information on redundant hot-standby supervisor.
The Cisco Catalyst 4500 ports are independent of the supervisor state. Because of this hardware design,
during a supervisor switchover, the ports connected to the failed supervisor do not go down. Because
paths and ports are not down, hardware keeps forwarding the packet to a valid next-hop while supervisor
switchover is occurring.
The configuration and implementation guidelines for implementing NSF/SSO on the Cisco Catalyst
4500 are the same for district office and school site network designs.
Increasing Supervisor Uplink Port Availability
There are restrictions on which supervisor uplink ports can be actively configured. Multiple ports can be
simultaneously active on the supervisor. However Cisco IOS Release 12.2(25)SG or later is required for
concurrent use of both 10G and 1G. The Schools SRA uses the 1G interface to connect to the Cisco
3750-MetroE WAN aggregation switch. To use 10G port in 1G mode with redundancy, the following
configuration must be applied on collapsed core Catalyst 4500 switch:
cr24-4507-DO(config)#hw-module uplink mode shared-backplane
cr24-4507-DO(config)#hw-module module 3 port-group 1 select gigabitethernet
cr24-4507-DO(config)#hw-module module 4 port-group 1 select gigabitethernet
cr24-4507-DO#show hw-module uplink
Active uplink mode configuration is Shared-backplane
Stateful Switchover (SSO)
SSO redundancy mode in the Cisco Catalyst 4500 supervisor is turned on by default starting with Cisco
IOS Release 12.2(20)EWA. To provide 1+1 redundancy, all the technical specifications between active
and standby supervisor must be identical. Also note that the Cisco Catalyst 4507R and 4510R are the
only models that support supervisor redundancy. SSO is supported on all supervisors running IOS except
Sup II-Plus-TS. The NSF-awareness feature is supported by all the supervisors supporting EIGRP,
OSPF, IS-IS, and BGP routing protocols, while the NSF-capable feature is supported only on supervisors
IV, V, and V-10G. NSF/SSO on Catalyst 4500 requires a minimum boot ROM version and must be the
same on both supervisors. For additional details on hardware requirements, refer to the Release Notes at
the following URL:
http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/53SG/configuration/NSFwSSO.html
#wp1135767
cr24-4507-DO(config)#redundancy
cr24-4507-DO(config-red)# mode sso
cr24-4507-DO(config-red)# main-cpu
cr24-4507-DO(config-r-mc)# auto-sync standard
cr24-4507-DO#show module | inc Chassis | 6-E | SSO
Chassis Type : WS-C4507R-E
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3
4
3
4
6
6
Sup 6-E 10GE (X2), 1000BaseX (SFP)
Sup 6-E 10GE (X2), 1000BaseX (SFP)
Active Supervisor
Standby Supervisor
WS-X45-SUP6-E
WS-X45-SUP6-E
JAE1132SXQ3
JAE1132SXRQ
SSOActive
SSOStandby hot
The active supervisor dynamically detects the secondary supervisor installed in the same chassis and
initiates several SSO dependency configuration checks. If the SSO dependency check fails, then the
standby supervisor falls back into RPR mode. For example, IOS release mismatch between two
supervisors may not allow SSO to synchronize.
If the SSO dependency configuration checks successfully pass, then SSO communication between both
supervisors goes through several synchronization states before it transitions to hot-standby state as
illustrated in the following output:
cr24-4507-DO#show redundancy states
my state = 13 -ACTIVE
peer state = 8 -STANDBY HOT
. . .
Redundancy Mode (Operational) = Stateful Switchover
Redundancy Mode (Configured) = Stateful Switchover
Redundancy State
= Stateful Switchover
Maintenance Mode = Disabled
Manual Swact = enabled
Communications = Up
. . .
All the state-machines and dynamic information of SSO-capable protocols are automatically
synchronized to the standby supervisor module without any additional operational requirement. The
hot-standby supervisor takes over the ownership of control-plane process when the active supervisor
outage or removal from the chassis is detected.
Non-Stop Forwarding (NSF)
All the state-machines and dynamic information of SSO-capable protocols are automatically
synchronized to the standby supervisor module. The hot-standby supervisor takes over the ownership of
control-plane process if the active supervisor suffers an outage or is removed from the chassis.
NSF-Capable Layer 3 Switch
cr24-4507-DO(config)#router eigrp 100
cr24-4507-DO (config-router)#nsf
cr24-4507-DO#show ip protocols | inc NSF
*** IP Routing is NSF aware ***
EIGRP NSF-aware route hold timer is 240
EIGRP NSF enabled
NSF signal timer is 20s
NSF converge timer is 120s
NSF Aware Layer 3 Switch
cr24-3560r-DO#show ip protocols | inc NSF
*** IP Routing is NSF aware ***
EIGRP NSF-aware route hold timer is 240
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WAN Design
In the Schools Service Ready Architecture, the school sites are connected to the district office over Wide
Area Network (WAN) links. This section discusses how to design and deploy the WAN for Schools SRA.
The primary components of WAN architecture are as follows:
•
WAN technology
•
Bandwidth capacity planning
•
WAN IP addressing structure
•
Routing
•
QoS
WAN Technologies
There are several WAN technologies available today to provide WAN services, such as MPLS/VPN,
Internet, and Metro Ethernet. MPLS/VPN provides Layer-2 or Layer-3 VPN services. It provides the
capability for an IP network infrastructure that delivers private network services over a shared network
infrastructure. To learn more about deploying MPLS/VPN, refer to the following URL:
http://www.cisco.com/en/US/solutions/ns340/ns414/ns742/ns817/landing_overall_wan.html
Internet service is the least expensive and easiest to deploy. Deploying a VPN service over the Internet
requires an overlay VPN network such as DMVPN to provide secure VPN service.
Metro Ethernet is one of the fastest growing transport technologies in the telecommunications industry.
The Schools SRA design uses Metro Ethernet service as the WAN transport between school sites, and
the district office.
Figure 3-44 depicts the WAN technologies available today.
Figure 3-44
WAN technologies
MPLS VPN
Ethernet over MPLS
Ethernet access to
MPLS
Internet
Leased Line
Ethernet Handoff
Broadband
Metro
Ethernet
227580
Next-Generation WAN/MAN
Metro Ethernet offers several distinct advantages for the Schools SRA WAN design:
•
Low latency and delay variation—Make it the best solution for video, voice and data
•
Low Cost—Carrier Ethernet brings the cost model of Ethernet to the WAN
•
Performance, QoS and Suitability for Convergence—Ethernet networks inherently require less
processing to operate and manage and operate at higher bandwidth than other technologies
•
Scalability, Ubiquity and Reachability—Global availability of standardized services independent
of physical access type dramatically reduce complexity and cost
Types of Metro Ethernet Services
Metro Ethernet typically offers two popular services:
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•
E-line, which is also known as Ethernet Virtual Private Line (EVPL), provides a point-to-point
service.
•
E-LAN provides multi-point or any-to-any connectivity.
EVPL, like Frame Relay, provides for multiplexing multiple point-to-point connections over a single
physical link. In the case of Frame Relay, the access link is a serial interface to a Frame Relay switch
with individual data-link connection identifiers (DLCIs) identifying the multiple virtual circuits or
connections. In the case of EVPL, the physical link is Ethernet, typically FastEthernet or Gigabit
Ethernet, and the multiple circuits are identified as VLANs through an 802.1q trunk.
E-LAN is also known as Virtual Private LAN Services (VPLS). One of its major advantages is any to
any connectivity within the metro area, which allows flexibility. It passes 802.q trunks across the SP
network known as Q-in-Q. Figure 3-45 shows the difference between these services.
Figure 3-45
Different Services Available
E-LAN
227581
E-Line
Service Deployed in the Design
Schools SRA design uses E-line with point-to-point service tp connect school sites to the district office.
Each school site has a 100 Mbps Metro point-to-point connection to the service provider Network. As
mentioned in the previous section, each circuit is represented by a VLAN using dot1q trunk. Figure 3-46
illustrates how this is implemented.
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EVPN Service Used in School WAN Architecture
Virtual Circuit
Point-To-Point
Main School District
School Site 1
Service
Provider
School Site 2
School Site 3
227582
Figure 3-46
Following is a sample configuration of the WAN interface at the district office:
interface GigabitEthernet1/1/1
description Connected to SP-MPLS-Core-cr24-6500-1
switchport trunk native vlan 801
switchport trunk allowed vlan 501-550
switchport mode trunk
logging event trunk-status
load-interval 30
carrier-delay msec 0
priority-queue out
mls qos trust dscp
spanning-tree portfast trunk
spanning-tree bpdufilter enable
spanning-tree guard root
service-policy output School-1to50-Parent-Policy-Map
hold-queue 2000 in
hold-queue 2000 out
In the above configuration, the link is carrying 50 VLANs, which are connected to 50 school sites.
Bandwidth Capacity
Planning sufficient bandwidth capacity is a critical component of the overall WAN design. Application
performance depends largely on guaranteed level of bandwidth at school sites and the district office. This
section discusses the general WAN bandwidth capacity planning steps, and how this has been
implemented in the School SRA.
Planning
The School district must purchase the MetroE service from the local Service Provider. The amount of
bandwidth capacity at each school, and at the district office must be sufficient to meet the anticipated
network load, and some margin for peak usage, and to allow future growth. The bandwidth is shared
based on the four-class QoS model, for optimal service delivery, as described in the “Deploying QoS in
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School Network” section on page 3-50. Logical bandwidth assignment to each circuit must be symmetric
at the school and at the district office. A mismatch in bandwidth capacity will force traffic drop in the
SP core due to in-consistent bandwidth SLAs.
The WAN bandwidth capacity may vary between school sites, but the design principles and
implementation (bandwidth sharing, routing, QoS, multicast) are the same.
Note
The district office WAN router is an aggregator that logically connects to multiple schools over a single
media. The School SRA district office WAN device is the Cisco 3750ME. The media type connecting to
the Metro WAN MUST be GigE, since the 3750ME does not negotiate to lower speeds.
Calculating the optimum guaranteed bandwidth required at the district office is done by considering the
following factors:
•
Number of school sites.
•
Bandwidth required at each location.
•
Platform scalability limits, mainly, at district office.
To describe how much bandwidth is required at each school site, we use two terms, CIR, Interface speed.
•
CIR—Committed bandwidth that is guaranteed from the service provider, based on the logical
connection.
•
Interface speed—The interface speed is actual Ethernet handoff, which is 1Gbps for both school
sites and district office.
For example, let us consider a scenario where there are three school sites, and one district office. The
CIR required at each school site is 100Mbps, and since there are three school sites, the district office
needs three virtual circuits each having a CIR of 100Mbs, which also means that the aggregate
bandwidth at district office is 300Mbps. Figure 3-47 illustrates this point.
Figure 3-47
Bandwidth Capacity Panning for Three School Sites
Interface Speed: 1000Mbps
CIR Bandwidth: 100Mbps
Interface Speed: 1000Mbps
CIR Bandwidth for each site: 100Mbps
Aggregate Bandwidth Capacity: 300Mbps
School Site 1
Service
Provider
School Site 2
School Site 3
227584
Main School District
Similarly, if the CIR required at each school site is 100Mbps, and if there are 100 school sites, then the
bandwidth required at the district office is 10Gbps. To support an aggregate CIR bandwidth of 10Gbps
at district office, we need to think about scalability limits on the WAN aggregation box.
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WAN Design
If the aggregated logical connection speed to the schools exceed the media capacity on 3750-ME, which
is the WAN aggregator for our design, then there are two design options:
1.
Migrate to Modular a switching platform (such as Catalyst 6500)—Migrating to a modular
switching platform in the WAN aggregation tier enables higher bandwidth, capacityy, and may
reduce operational and management complexities.
2.
Deploy another 3750-ME —Deploying another 3750-ME is the simplest way to scale the WAN
capacity. Deploying another set of 3750-ME does not change any WAN design principles, and
except for VLAN and IP address, all the configurations can be replicated to the secondary system.
Implementation
This section describes how the WAN is implemented in the Schools SRA reference design, which was
validated in the lab:
•
The district office has dual WAN connections, and each connection is 1Gbps.
•
On each WAN connection there are 50 Virtual circuits, each with CIR of 20Mbps.
•
The school sites have 1Gbps connection, and CIR value of 20Mbs on each circuit.
Figure 3-48 shows how this design is validated with 100 school sites.
Figure 3-48
Bandwidth Capacity Planning for 100 School Sites
School Site 1
Interface Speed: 1000Mbps
CIR Bandwidth: 20Mbps
Interface Speed: 1000Mbps
CIR Bandwidth for each site: 20Mbps
Aggregate Bandwidth Capacity: 1000Mbps
Main School District
School Site 50
Service
Provider
Interface Speed: 1000Mbps
CIR Bandwidth for each site: 20Mbps
Aggregate Bandwidth Capacity: 1000Mbps
School Site 100
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Interface Speed: 1000Mbps
CIR Bandwidth: 20Mbps
School Site 11
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IP Address Aggregation
This section describes how to aggregate IP address space at the school sites, and the district office on the
WAN interface.
As explained in the previous section, all the school sites are connected to the district office using
point-to-point links, which means that every school site should be on a different IP subnet. It is common
for customers to deploy using /30 subnet for each school site. This uses up to four addresses for each
subnet. Best practice recommendation is to use /31 subnets. This approach only uses two addresses in
each link. The following configuration shows how to deploy this at a school site or district office:
School site
District office
interface Vlan501
description Connected to cr24-3750ME-DO
dampening
ip address 10.126.0.1 255.255.255.254
no ip redirects
no ip unreachables
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip pim sparse-mode
ip summary-address eigrp 100 10.127.0.0
255.255.248.0 5
load-interval 30
interface Vlan501
description Connected to cr35-4507-SS1
dampening
ip address 10.126.0.0 255.255.255.254
no ip redirects
no ip unreachables
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip pim sparse-mode
ip summary-address eigrp 100 10.124.0.0 255.252.0.0
5
load-interval 30
hold-queue 2000 in
hold-queue 2000 out
Routing for WAN Connections
This section discusses how to implement routing on the WAN interfaces. The key consideration when
designing the routing protocol is summariztion.
•
Summarization on network boundaries is very important to design as it prevents unnecessary routing
updates to flow across the WAN interface, when there is a link-state change in the network. For
example, let us consider a school district where there are subnets in the following range:
10.127.0.0/26
10.127.0.64/26
10.127.0.128/26
.
.
.
10.127.7.64/26
Since the above subnets belong to a particular school district, they could be summarized as
10.127.0.0/21. The following configuration shows how to perform summarization on the WAN interface,
which is Vlan501 in this example:
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School site
District office
interface Vlan501
description Connected to cr24-3750ME-DO
dampening
ip address 10.126.0.1 255.255.255.254
no ip redirects
no ip unreachables
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip pim sparse-mode
ip summary-address eigrp 100 10.127.0.0 255.255.248.0
5
load-interval 30
interface Vlan501
description Connected to cr35-4507-SS1
dampening
ip address 10.126.0.0 255.255.255.254
no ip redirects
no ip unreachables
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip pim sparse-mode
ip summary-address eigrp 100 10.124.0.0 255.252.0.0 5
load-interval 30
hold-queue 2000 in
hold-queue 2000 out
WAN QoS Design
QoS design is particularly important when using Ethernet as the WAN, since the router or switch on the
WAN edge might believe they have complete line rate available to transmit. If the WAN device transmits
at full line rate into the WAN, the Service Provider network will drop packets exceeding the CIR (i.e.
the committed rate agreed to with Service Provider). Figure 3-49 shows what may happen without a
proper QoS design.
Figure 3-49
Policing at Service provider due to lack of proper QoS at district office, and school
sites
ow
Inbound Policing
c
ffi
a
Tr
Traffic Flow
Main School District
Service
Provider
School Site 1
Fl
Traffic Flow
Tr
School Site 2
af
fic
Fl
School Site 3
227586
ow
Proper QoS policies implemented at the district office and school site will prevent packets from being
dropped at service provider network.
WAN QoS Policy at District Office
The district office has several point to point circuits; one connecting to each school site. The QoS policy
at the district office has the following objectives:
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WAN Design
•
The aggregate traffic going out to the school site does not exceed the school site CIR (20Mbps for
the lab testbed).
•
All the traffic going out is put into four classes.
To accomplish the above objectives, Hierarchical Class Based Weighted Fair Queuing (HCBWFQ) is
implemented. To learn more about HCBWFQ, refer Ethernet Access for Next Generation Metro and
Wide Area Networks Design Guide at the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/Ethernet_Access_for_NG_M
AN_WAN_V3.1_external.html
Implementing HCWFQ requires the following two policies:
•
Parent policy that defines the aggregate shape rate
•
Child policy that enables queuing within the shaped rate.
Figure 3-50 shows the representation of hierarchical policy.
Figure 3-50
Hierarchical policy implementation at District office
GE Speed Interface
to SP MetroE
1
Parent Policy: Per-Port aggregated Traffic Shape
from District School to all remote School Sites
VLAN 502
Remote School Site 1
1
VLAN 501
Remote School Site 2
Parent Policy:
Per-VLAN Sub-rate
Traffic Shaping to
Remote School Site 1
Parent Policy:
Per-VLAN Sub-rate
Traffic Shaping to
Remote School Site 2
1
Child Policy: Per-VLAN Queueing
Queue-1 – Real-time Class (PQ) – 30% of Per-VLAN BW
Queue-2 – Gold Class (CBWFQ) – 5% of Per-VLAN BW
Queue-3 – Silver Class (CBWFQ) – 30% of Per-VLAN BW
Queue-4 – Best-Effort (WFQ/WRED) – 35% of Per-VLAN BW
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2
The following table shows how these classes are defined:
Class
Queuing type
Bandwidth Allocation
REAL_TIME
LLQ
30%
GOLD
CBWFQ
5%
SILVER
CBWFQ
30%
DEFAULT
CBWFQ
35%
Following is the configuration of the QoS policy at the district office. This configuration is for one
VLAN:
class-map match-all School_Site1 <-This class map would match the traffic going to a
school site
description cr2-4507-SS1
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match vlan
501
policy-map School-Child-Policy-Map <- This is child policy
class REAL_TIME
priority
police cir percent 30 conform-action set-cos-transmit 5 exceed-action drop
violate-action drop
class GOLD
bandwidth percent 5
set cos 3
class SILVER
bandwidth percent 30
set cos 2
class class-default
bandwidth percent 35
set cos 0
!
Following is the configuration of the parent policy, which shapes to 20Mbps for each school site in this
example:
Policy Map School-1to50-Parent-Policy-Map <-This is parent policy map
Class School_Site1
shape average 20000000 (bits/sec)
service-policy School-Child-Policy-Map <-This is child policy map
After defining the policies, they are applied to WAN interfaces. The following example shows the
configuration of Metro switch on its WAN interface:
interface GigabitEthernet1/1/1
description Connected to SP-MPLS-Core-cr24-6500-1
switchport trunk native vlan 801
switchport trunk allowed vlan 501-550
switchport mode trunk
logging event trunk-status
load-interval 30
carrier-delay msec 0
priority-queue out
mls qos trust dscp
spanning-tree portfast trunk
spanning-tree bpdufilter enable
spanning-tree guard root
max-reserved-bandwidth 100
service-policy output School-1to50-Parent-Policy-Map <-The policy-map
hold-queue 2000 in
hold-queue 2000 out
After completing the QoS policy at district office, we need to define the QoS policy at school sites.
WAN QoS Policy at School Site
The objectives at the school sites are similar to the one at the district office, which is:
•
Ensure that 20Mbps is the maximum aggregate traffic leaving the WAN device.
•
Ingress traffic is queued in four classes.
The school site implementation is different from the district office (due to lack of HCBWFQ support).
The following configuration shows how to implement the Qos policy without HCBWFQ.
The first step is to queue the ingress traffic in the four queues. The following table shows the queues,
and the bandwidth allocated for each:
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The first step is to queue the ingress traffic in the four queues. The following table shows the queues,
and the bandwidth allocated for it:
Class
Queuing type
Bandwidth Allocation
REAL_TIME
Per-class
6mbps
GOLD
Per-class
1mbps
SILVER
Per-class
7mpbs
DEFAULT
Per-class
6mbps
Following is the configuration of egress interface on the school-site:
interface GigabitEthernet1/1
description Connected to MetroE-Core-cr25-6500-1
switchport trunk encapsulation dot1q
switchport trunk native vlan 801
switchport trunk allowed vlan 501
switchport mode trunk
logging event link-status
load-interval 30
carrier-delay msec 0
qos trust dscp
udld port disable
tx-queue 1
bandwidth 1 mbps
tx-queue 2
bandwidth 7 mbps
tx-queue 3
bandwidth 6 mbps
priority high
tx-queue 4
bandwidth 6 mbps
no cdp enable
spanning-tree portfast trunk
spanning-tree bpdufilter enable
spanning-tree guard root
service-policy output WAN-EGRESS-PARENT
The above configuration ensures that each class of traffic is queued as per the table shown above.
However, the “bandwidth” would only ensure the minimum amount of bandwidth available. It does not
control the upper threshold, which needs to be 20Mbps in our example. Therefore, to make sure that the
traffic on the egress interface does not exceed 20Mps, we have a WAN-EGRESS-PARENT policy that
polices the traffic to 20Mbps. Following is the configuration of the WAN egress policy:
cr35-4507-SS1#show policy-map WAN-EGRESS-PARENT
Policy Map WAN-EGRESS-PARENT
Class class-default
police 20 mbps 1000 byte conform-action transmit exceed-action drop
service-policy WAN-EGRESS-CHILD
cr35-4507-SS1#
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4
Security Design
Introduction
The Cisco Service Ready Architecture (SRA) for Schools solution is designed with security to provide
a safe online environment for teaching and learning. Following the proven guidelines of the Cisco SAFE
Security architecture, a series of security technologies and products are strategically deployed
throughout the solution to protect minors from harmful and inappropriate content, to guarantee the
confidentiality of student, staff and faculty private data, and to ensure the availability and integrity of the
systems and data.
Protecting the infrastructure and keeping students and staff safe requires the implementation of security
controls capable of mitigating both well-known and new forms of threats. Common threats to school
environments include:
•
Service disruption—Disruption of the administrative infrastructure and learning resources such as
computer labs caused by botnets, worms, malware, adware, spyware, viruses, DoS attacks.
•
Harmful or inappropriate content—Pornography, adult, aggressive, offensive and other type of
content that could put the physical and psychological well being of minors at risk.
•
Network abuse—Peer-to-peer file sharing and instant messaging abuse, use of non-approved
applications by students, staff, and faculty.
•
Unauthorized access—Intrusions, unauthorized users, escalation of privileges, and unauthorized
access to learning and administrative resources.
•
Data loss—Theft or leakage of student, staff and faculty private data from servers, endpoints, and
while in transit, or as a result of spyware, malware, key-loggers, viruses, etc.
The solution design follows a defense-in-depth approach, whereby multiple layers of protection are built
into the architecture. Different security products and technologies are combined together for enhanced
security visibility and control. Figure 4-1 illustrates the security design and its product positioning.
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Introduction
Figure 4-1
SRA Security Design
Network Access Control
Authentication and policy enforcement via Cisco
Identity-Based Networking Services (IBNS). Rolebased access control and device security compliance
via Cisco Network Admission Control (NAC).
Data Center
Network Foundation Protection
Device hardening, control and management plane protection throughout the
entire infrastructure to maximize availability
and resiliency.
Threat Detection and Mitigation
Intrusion prevention and infrastructure based
network telemetry to identify and mitigate threats.
Access
IP
Video
Surveillance
Media Server
NAC
Manager
Core
Distribution
Cisco ACS
Appliance
SRST/Video
Gateway
Cisco Unified
Communications
Manager
Internet Access
Email and web-security. Stateful firewall
inspection. Intrusion prevention and global
correlation. Granular access control.
Catalyst Integrated Security Features
Layer 2 protection provided by port security,
Dynamic ARP inspection, IP Source guard,
DHCP snooping.
Internet Edge
Cisco ASA
NAC Server
Internet
www
V
Cisco IPS
Web
Security
M
District Office
SensorBase
Email
Security
SP Managed
MetroE Core
Enhanced Availability and
Resiliency
Hardened devices and high
availability design ensure
optimal service availability.
System and interface-based
redundancy.
NAC
Server
IP
IP
Unified Communications
Security and emergency
services, enhanced 911
support. Conferencing and
collaboration for planning
and emergency response.
227420
Cisco Video Surveillance
Monitor activities throughout
the school environment to
prevent and deter safety
incidents.
NAC
Server
Endpoint Security
Desktop endpoint protection
for day-zero attack protection,
data loss prevention, and
signature-based antivirus.
School Sites
The security design focuses on the following key areas:
•
Network Foundation Protection (NFP)— Ensuring the availability and integrity of the network
infrastructure, protecting the control and management planes.
•
Internet Perimeter Protection— Ensuring safe Internet connectivity, and protecting internal
resources and users from malware, viruses, and other malicious software. Protecting students and
staff from harmful and inappropriate content. Enforcing E-mail and web browsing policies.
•
Network Access Security and Control—Securing the access edges. Enforcing authentication and
role-based access for students, staff and faculty residing at school sites and district office. Ensuring
systems are up-to-date and in compliance with the school’s network security policies.
•
Network Endpoint Protection—Protecting students, staff and faculty from harmful and
inappropriate content. Enforcing E-mail and web browsing policies.
The design guidelines and best practices for each focus area are discussed next. For more detailed
information, refer to the Cisco SAFE Reference Guide at the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Security/SAFE_RG/SAFE_rg.html
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Network Foundation Protection
Network Foundation Protection
School networks are built with routers, switches, and other network devices that keep the applications
and services running. Therefore, properly securing these network devices is critical for continued
operation.
The SRA solution protects the network infrastructure by implementing the Cisco SAFE best practices
for the following areas:
•
Infrastructure device access
– Restrict management device access to authorized parties and for the authorized ports and
protocols.
– Enforce Authentication, Authorization and Accounting (AAA) with TACACS+ or RADIUS to
authenticate access.
– Authorize actions and log all administrative access.
– Display legal notification banners.
– Ensure confidentiality by using secure protocols like SSH and HTTPS.
– Enforce idle and session timeouts.
– Disable unused access lines.
•
Routing infrastructure
– Restrict routing protocol membership by enabling MD5 neighbor authentication and disabling
default interface membership.
– Enforce route filters to ensure that only legitimate networks are advertised, and networks that
are not supposed to be propagated are never advertised.
– Log status changes of neighbor sessions to identify connectivity problems and DoS attempts on
routers.
•
Device resiliency and survivability
– Disable unnecessary services, implement control plane policing (CoPP).
– Enable traffic storm control.
– Implement topological, system and module redundancy for the resiliency and survivability of
routers and switches and to ensure network availability.
– Keep local device statistics.
•
Network telemetry
– Enable NTP time synchronization.
– Collect system status and event information with SNMP, Syslog, TACACS+/RADIUS
accounting.
– Monitor CPU and memory usage on critical systems.
•
Network policy enforcement
– Implement access edge filtering.
– Enforce IP spoofing protection with access control lists (ACLs), Unicast Reverse Path
Forwarding (uRPF) and IP Source Guard.
•
Switching infrastructure
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Internet Perimeter Protection
– Implement a hierarchical design, segmenting the LAN into multiple IP subnets or VLANS to
reduce the size of broadcast domains.
– Protect the Spanning Tree Protocol (STP) domain with BPDU Guard, STP Root Guard.
– Use Per-VLAN Spanning Tree to reduce the scope of possible damage.
– Disable VLAN dynamic trunk negotiation on user ports.
– Disable unused ports and put them into an unused VLAN.
– Enable Traffic Storm Control.
– Implement Catalyst Infrastructure Security Features (CISF) including port security, Dynamic
ARP Inspection, and DHCP snooping.
– Use a dedicated VLAN ID for all trunk ports.
– Explicitly configure trunking on infrastructure ports.
– Use all tagged mode for the native VLAN on trunks and drop untagged frames.
•
Network management
– Ensure the secure management of all devices and hosts within the school network architecture.
– Authenticate, authorize and keep record of all administrative access.
– If possible, implement a separate out-of-band (OOB) management network (hardware or
VLAN-based) to manage systems local at the District Office.
– Secure the OOB by enforcing access controls, using dedicated management interfaces or VRFs.
– Provide secure in-band management access for systems residing at the school sites by deploying
firewalls and ACLs to enforce access controls, using Network Address Translation (NAT) to
hide management addresses, and use secure protocols like SSH and HTTPS.
– Ensure time synchronization by using NTP. Secure servers and other endpoint with endpoint
protection software and operating system (OS) hardening best practices.
Configurations are shown in the design chapters. For more detailed information on the NFP best
practices, refer to “Chapter 2, Network Foundation Protection” of the Cisco SAFE Reference Guide at
the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Security/SAFE_RG/chap2.html
Internet Perimeter Protection
The school architecture assumes the existence of a centralized Internet connection at the district office,
serving students, staff and faculty residing at all school premises. Common services typically provided
include E-mail for staff and faculty, Internet browsing for everyone, and a school web portal accessible
over the Internet. Other services may also be provided using the same infrastructure.
The network infrastructure that provides Internet connectivity is defined as the Internet perimeter,
illustrated in Figure 4-2.
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Internet Perimeter Protection
Figure 4-2
Internet Perimeter
Network Foundation Protection
Device hardening, control and management plane protection throughout the
entire infrastructure to maximize availability
and resiliency.
Access
Threat Detection and Mitigation
Intrusion prevention and infrastructure
based network telemetry to identify
and mitigate threats.
Core
Distribution
Internet Access
Email and web-security. Stateful firewall
inspection. Incline intrusion prevention
and global correlation. Granular access
control.
Internet Edge
Internet
Border
Router
Cisco ASA
Internet
SensorBase
Cisco IPS
MetroE Core
www
Web
Security
Mail
Server
Enhanced Availability and Resiliency
Hardened devices and high availability
design ensure optimal service availability.
System and interface-based redundancy.
Email
Security
Public Services DMZ
Endpoint server protection, intrusion
prevention, stateful firewall inspection, application deep-packet
inspection, DDoS protection.
Web
Server
Edge Protection
Traffic filtering, routing security, firewall
integration and IP spoofing protection to
discard anomalous traffic flows, prevent
unauthorized access and block illegitimate
traffic.
227421
SP Managed
MetroE Core
The primary functions of the Internet perimeter is to allow for safe and secure access to students, staff,
and faculty, and to provide public services without compromising the confidentiality, integrity, and
availability of school resources and data. To that end, the Internet perimeter incorporates the following
security functions:
•
Internet Border Router—This is the Internet gateway responsible for routing traffic between the
school and the Internet. The Internet border router may be administered by school personnel or may
be managed by the Internet service provider (ISP). The router provides the first line of protection
against external threats and should be hardened using the Network Foundation Protection (NFP) best
practices.
•
Internet Firewall—A Cisco Adaptive Security Appliance provides Stateful access control and deep
packet inspection to protect the school resources and data from unauthorized access and disclosure.
The security appliance is configured to prevent incoming access from the Internet, to protect the
school web portal and other Internet public services, and to control student, staff and faculty traffic
bound to the Internet. The security appliance may also implement an Advanced Inspection and
Prevention Security Services Module (AIP SSM) for enhanced threat detection and mitigation. This
IPS module may be configured either in inline or promiscuous mode. The security appliance may
also provide secure remote access to faculty, staff, and students in the form of IPSec or SSL VPN.
•
Public Services DMZ—The Internet school web portal, mail server, and other public-facing services
may be placed on a demilitarized zone (DMZ) for security and control purposes. The DMZ acts as
a middle stage between the Internet and school's private resources, preventing external users from
directly accessing any internal servers and data. The Internet firewall is responsible for restricting
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incoming access to the public services and by limiting outbound access from DMZ resources out to
the Internet. Systems residing on the DMZ are hardened with endpoint protection software (i.e.,
Cisco Security Agent) and operating system (OS) hardening best practices.
•
E-mail Security—A Cisco Ironport C Series E-mail Security Appliance (ESA) is deployed at the
DMZ to inspect incoming and outgoing E-mails and eliminate threats such as E-mail spam, viruses,
and worms. The ESA appliance also offers E-mail encryption to ensure the confidentiality of
messages, and data loss prevention (DLP) to detect the inappropriate transport of sensitive
information.
•
Web Security—A Cisco IronPort S Series Web Security Appliance (WSA) is deployed at the
distribution switches to inspect HTTP and HTTPS traffic bound to the Internet. This system enforces
URL-filtering policies to block access to websites containing content that may be harmful or
inappropriate for minors or that are known to be the source of spyware, botnets, or other type of
malware. The WSA is also responsible for the monitoring of Layer-4 traffic for rogue activity and
infected systems.
The following subsections describe the design guidelines for implementing the security functions.
Note
For implementation details on Remote Access VPN, IPS, CSA, and Internet border router hardening,
refer to the Cisco SAFE Reference Guide at the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Security/SAFE_RG/SAFE_rg.html. Firewall
and web security configurations can be found in Chapter 11, “District Office Design.”
Internet Border Router Guidelines
The Internet border router provides connectivity to the Internet via one or more Internet service
providers. The router act as the first line of defense against unauthorized access, DDoS, and other
external threats. Access control lists (ACLs), uRPF, and other filtering mechanisms may be implemented
for anti-spoofing and to block invalid packets. NetFlow, Syslog, and SNMP may be used to gain
visibility on traffic flows, network activity and system status. In addition, the Internet border router
should be secured.This includes restricting and controlling administrative access, protecting the
management and control planes, and securing the dynamic exchange of routing information.
Chapter 11, “District Office Design”provides an example of Internet edge ACL. For more information
on how to configure the Internet border router, refer to “Internet Edge” chapter of the Cisco SAFE
Reference Guide at the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Security/SAFE_RG/SAFE_rg.html.
Internet Firewall Guidelines
The Cisco Adaptive Security Appliance (Cisco ASA) deployed at the Internet perimeter is responsible
for protecting the school’s internal resources and data from external threats by preventing incoming
access from the Internet; protecting public resources served by the DMZ by restricting incoming access
to the public services and by limiting outbound access from DMZ resources out to the Internet; and
controlling user's Internet-bound traffic.
To that end, the security appliance is configured to enforce access policies, keep track of connection
status, and inspect packet payloads following these guidelines:
•
Deny any connection attempts originating from the Internet to internal resources and subnets.
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Internet Perimeter Protection
•
Allow outbound Internet HTTP/HTTPS access for students, staff and faculty residing at any of the
school premises.
•
Allow outbound Internet SSL access for administrative updates, SensorBase, IPS signature updates,
etc.
•
Allow students, staff and faculty access to DMZ services such as school web portal, E-mail, and
domain name resolution (HTTP, SMTP, POP, IMAP, and DNS).
•
Restrict inbound Internet access to the DMZ for the necessary protocols and servers (HTTP to Web
server, SMTP to Mail Transfer Agent, DNS to DNS server, etc.).
•
Restrict connections initiated from DMZ to the only necessary protocols and sources (DNS from
DNS server and mail server, SMTP from mail server, SSL for Cisco IronPort ESA).
•
Enable stateful inspection for the used protocols to ensure returning traffic is dynamically allowed
by the firewall.
•
Implement Network Address Translation (NAT) and Port Address Translation (PAT) to shield the
internal address space from the Internet.
Figure 4-3 illustrates the protocols and ports explicitly allowed by the Cisco ASA.
Figure 4-3
Allowed Protocols and Ports
INSIDE
OUTSIDE
HTTP, HTTPS
DMZ
HTTP, HTTPS, DNS, SMTP
HTTP, HTTPS, DNS, SMTP
Note
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HTTP, HTTPS, DNS, POP,
IMAP, SMTP
Allowed Protocols and Ports does not include any management traffic destined to the firewall. Whenever
available, a dedicated management interface should be used. In case the firewall is managed in-band,
identify the protocols and ports required prior to configuring the firewall ACLs.
In addition, the Cisco ASA should be hardened following the NFP best practices. This includes
restricting and controlling administrative access, securing the dynamic exchange of routing information
with MD5 authentication, and enabling firewall network telemetry with SNMP, syslog, and NetFlow.
In the school design, higher availability is achieved by using redundant physical interfaces. This
represents the most cost-effective solution for high availability. As an alternative, a pair of firewall
appliances could be deployed in stateful failover, as discussed in Chapter 11, “District Office Design.”
E-mail Security Guidelines
The Cisco Ironport C Series E-mail Security Appliance (ESA) deployed at the DMZ is responsible for
inspecting E-mails and eliminating threats such as E-mail spam, viruses and worms. The ESA can be
described as a firewall and threat monitoring system for Simple Mail Transfer Protocol (SMTP) traffic
(TCP port 25). Logically speaking, the ESA acts as a Mail Transfer Agent (MTA) within the E-mail
delivery chain, as illustrated in Figure 4-4. Upon reception, E-mails are evaluated using a reputation
score mechanism based on the SensorBase network. The SensorBase network is an extensive network
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that monitors global E-mail and web traffic for anomalies, viruses, malware and other and abnormal
behavior. The network is composed of Cisco IronPort appliances, Cisco ASA and IPS appliances
installed in more than 100,000 organizations worldwide, providing a large and diverse sample of Internet
traffic patterns. By leveraging the SensorBase Network, messages originating from domain names or
servers known to be the source of spam or malware, and therefore with a low reputation score, are
automatically dropped or quarantined by preconfigured reputation filters. Optionally, the school may
choose to implement some of the other functions offered by the ESA appliance, including anti-virus
protection with virus outbreak filters and embedded anti-virus engines (Sophos and McAfee), encryption
to ensure the confidentiality of messages, and data loss prevention (DLP) for E-mail to detect
inappropriate transport of sensitive information.
Figure 4-4
E-mail Delivery Chain
Internet
Firewall
Cisco IronPort ESA
Email Server
Firewall
227423
Client
Figure 4-4 shows a logical implementation of a DMZ hosting the E-mail server and ESA appliance. This
can be implemented physically by either using a single firewall or two firewalls in sandwich.
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Figure 4-5
Common ESA Deployments
Dual-Armed
Single-Armed
Internet
Outside
Internet
Outside
DMZ
DMZ
Inside
IP x.x.x.x
Public Listener
Inside
Public Listener
IP x.x.x.x
Private Listener
IP y.y.y.y
Email
Server
227424
Email
Server
There are multiple deployment approaches for the security appliance depending on the number of
interfaces used (see Figure 4-5):
•
Dual-armed configuration—Two physical interfaces used to serve a public mail listener and a
private mail listener, each one configured with a separate logical IP address. The public listener
receives E-mail from the Internet and directs messages to the internal E-mail servers; while the
private listener receives E-mail from the internal servers and directs messages to the Internet. The
public listener interface may connect to the DMZ; while the public listener interface may connect
to the inside of the firewall.
•
One-armed configuration—A single ESA interface configured with a single IP address and used for
both incoming and outgoing E-mail. A public mail listener is configured to receive and relay E-mail
on that interface. The best practice is to connect the ESA interface to the DMZ where the E-mail
server resides.
For simplicity, the school architecture implements the ESA with a single interface. In addition, using a
single interface leaves other data interfaces available for redundancy.
Figure 4-6 illustrates the logical location of the ESA within the E-mail flow chain.
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Figure 4-6
Typical Data Flow for Inbound E-mail Traffic
Mail
Server
DNS
Server
2
1
3
Internet
4
6
7
5
ESA
8
9
227425
Mail
Server
The following steps explain what is taking place in Figure 4-6:
Step 1
Sender sends an E-mail to [email protected] X.
Step 2
What’s the IP address of domain X?
Step 3
It’s a.b.c.d (public IP address of ESA).
Step 4
E-mail server sends message to a.b.c.d using SMTP.
Step 5
Firewall permits incoming SMTP connection to the ESA, and translates its public IP address.
Step 6
ESA performs a DNS query on sender domain and checks the received IP address in its reputation
database, and drops, quarantines E-mail based on policy.
Step 7
ESA forwards E-mail to preconfigured inbound E-mail server.
Step 8
E-mail server stores E-mail for retrieval by receiver.
Step 9
Receiver retrieves E-mail from server using POP or IMAP.
The Internet firewall should be configured to allow communications to and from the Cisco IronPort ESA.
Protocols and ports to be allowed vary depending on the services configured on the appliance. For
details, refer to the Cisco IronPort User’s Guide at the following URL:
http://www.ironport.com/support/
The following are some of the most common services required:
•
Outbound SMTP (TCP/25) from ESA to any Internet destination
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•
Inbound SMTP (TCP/25) to ESA from any Internet destination
•
Outbound HTTP (TCP/80) from ESA to downloads.ironport.com and updates.ironport.com
•
Outbound SSL (TCP/443) from ESA to updates-static.ironport.com and
phonehome.senderbase.org
•
Inbound and Outbound DNS (TCP and UDP port 53)
•
Inbound IMAP (TCP/143), POP (TCP/110), SMTP (TCP/25) to E-mail server from any internal
client
In addition, if the ESA is managed in-band, appropriate firewall rules need to be configured to allow
traffic such as SSH, NTP, and syslog.
The Cisco IronPort ESA appliance functions as a SMTP gateway, also known as a mail exchange (MX).
The following are the key deployment guidelines:
•
Ensure that the ESA appliance is both accessible via the public Internet and is the first hop in the
E-mail infrastructure. If you allow another MTA to sit at your network’s perimeter and handle all
external connections, then the ESA appliance will not be able to determine the sender’s IP address.
The sender’s IP address is needed to identify and distinguish senders in the Mail Flow Monitor, to
query the SensorBase Reputation Service for the sender’s SensorBase Reputation Service Score
(SBRS), and to improve the efficacy of the anti-spam and virus outbreak filters features.
•
Features like Cisco IronPort Anti-Spam, Virus Outbreak Filters, McAfee Antivirus and Sophos
Anti-Virus require the ESA appliance to be registered in DNS. To that end, create an A record that
maps the appliance’s hostname to its public IP address, and an MX record that maps the public
domain to the appliance’s hostname. Specify a priority for the MX record to advertise the ESA
appliance as the primary (or backup during testing) MTA for the domain. A static address translation
entry needs to be defined for the ESA public IP address on the Internet firewall if NAT is configured.
•
Add to the Recipient Access Table (RAT) all the local domains for which the ESA appliance will
accept mail. Inbound E-mail destined to domains not listed in RAT will be rejected. External E-mail
servers connect directly to the ESA appliance to transmit E-mail for the local domains, and the ESA
appliance relays the mail to the appropriate groupware servers (for example, Exchange™,
Groupwise™, and Domino™) via SMTP routes.
•
For each private listener, configure the Host Access Table (HAT) to indicate the hosts that will be
allowed to send E-mails. The ESA appliance accepts outbound E-mail based on the settings of the
HAT table. Configuration includes the definition of Sender Groups associating groups or users, upon
which mail policies can be applied. Policies include Mail Flow Policies and Reputation Filtering.
Mail Flow Policies are a way of expressing a group of HAT parameters (access rule, followed by
rate limit parameters and custom SMTP codes and responses). Reputation Filtering allows the
classification of E-mail senders and to restrict E-mail access based on sender's trustworthiness as
determined by the IronPort SennsorBase Reputation Service.
•
Define SMTP routes to direct E-mail to appropriate internal mail servers.
•
If an out-of-band (OOB) management network is available, use a separate interface for
administration.
A failure on the ESA appliance may cause service outage, therefore a redundant design is recommended.
There are multiple ways to implement redundancy:
•
IronPort NIC Pairing—Redundancy at the network interface card level by teaming two of the
Ethernet interfaces on the ESA appliance. If the primary interface fails, the IP addresses and MAC
address are assumed by the secondary.
•
Multiple MTAs—Consists in adding a second ESA appliance or MTA with an equal cost secondary
MX record.
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•
Load Balancer—A load balancer such as Cisco ACE Application Control Engine (ACE)
load-balances traffic across multiple ESA appliances.
IronPort NIC pairing is the most cost-effective solution (see Figure 4-7), because it does not require the
implementation of multiple ESA appliances and other hardware. It does not, however, provide
redundancy in case of chassis failure.
Figure 4-7
Cisco IronPort ESA NIC Pairing
Internet
Firewall
DMZ
IP address, Secondary NIC
227426
IP address, Primary NIC
ESA
For more information on how to configure ESA, refer to the Cisco SAFE Reference Guide
(http://www.cisco.com/en/US/docs/solutions/Enterprise/Security/SAFE_RG/SAFE_rg.html) and
IronPort ESA User’s Guide (http://www.ironport.com/support/).
Web Security Guidelines
The school architecture implements a Cisco IronPort S Series Web Security Appliance (WSA) to block
access to sites with content that may be harmful or inappropriate for minors, and to protect the schools
from web-based malware and spyware.
Cisco IronPort WSA’s protection relies in two independent services:
Note
•
Web Proxy—This provides URL filtering, web reputation filters, and optionally anti-malware
services. The URL filtering capability defines the handling of each web transaction based on the
URL category of the HTTP requests. Leveraging the SensorBase network, the web reputation filters
analyze the web server behavior and characteristics to identify suspicious activity and protect
against URL-based malware. The anti-malware service leverages anti-malware scanning engines
such as Webroot and McAfee to monitor for malware activity.
•
Layer 4 Traffic Monitoring (L4TM)—Service configured to monitor all Layer-4 traffic for rogue
activity and to detect infected clients.
The SensorBase network is an extensive network that monitors global E-mail and web traffic for
anomalies, viruses, malware, and other abnormal behavior. The network is composed of the Cisco
IronPort appliances, Cisco ASA, and Cisco IPS appliances and modules installed in more than 100,000
organizations worldwide, providing a large and diverse sample of Internet traffic patterns.
As the school design assumes a centralized Internet connection, the WSA is implemented at the
distribution layer of the district office network. This allows the inspection and enforcement of web
access policies to all students, staff, and faculty residing at any of the school premises. Logically, the
WSA sits in the path between web users and the Internet, as shown in Figure 4-8.
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Figure 4-8
Cisco IronPort WSA
Internet
Firewall
www
Cisco IronPort WSA
227427
Client
There are two deployment modes for the Web Proxy service:
•
Explicit Forward Proxy—Client applications, such as web browsers, are aware of the Web Proxy and
must be configured to point to the WSA. The web browsers can be either configured manually or by
using Proxy Auto Configuration (PAC) files. The manual configuration does not allow for
redundancy, while the use of PAC files allows the definition of multiple WSAs for redundancy and
load balancing. If supported by the browser, the Web Proxy Autodiscovery Protocol (WPAD) can be
used to automate the deployment of PAC files. WPAD allows the browser to determine the location
of the PAC file using DHCP and DNS lookups.
•
Transparent Proxy—Client applications are unaware of the Web Proxy and do not have to be
configured to connect to the proxy. This mode requires the implementation of a Web Cache
Communications Protocol (WCCP) enable device or a Layer-4 load balancer in order to intercept
and redirect traffic to the WSA. Both deployment options provide for redundancy and load
balancing.
Explicit forward proxy mode requires the school to have control over the configuration of the endpoints,
which may not be always possible. For example, the school may allow students, staff and faculty to use
personal laptops, smart-phones and other devices outside the school's administration. Transparent proxy
mode, on the other hand, provides a transparent integration of WSA without requiring any configuration
control over the endpoints. It also eliminates the possibility of users reconfiguring their web browsers to
bypass the appliance without knowledge of the administrators. For these reasons, the school architecture
implements transparent proxy with WCCP. In this configuration, the Cisco ASA at the Internet perimeter
is leveraged as a WCCP server while the WSA act as a WCCP Traffic Processing Entity.
Note
It is recommended to enable both the Layer-4 traffic monitor and transparent proxy during the initial
System Setup Wizard. Either of these services can be disabled or reconfigured after initial setup from
the web interface. If you do not enable one of the features in the System Setup Wizard and then need to
enable it later, you must run the System Setup Wizard again, losing all configurations added to the
appliance.
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The Cisco ASA uses WCCP version 2, which has a built-in failover and load balancing mechanism. Per
WCCPv2 specification, multiple appliances (up to 32 entities) can be configured as part of the same
service group. HTTP and HTTPS traffic is load-balanced across the active appliances based on source
and destination IP addresses. The server (Cisco ASA) monitors the availability of each appliance in the
group, and can identify appliance failures within 30 seconds. After failure, traffic is redirected across the
remaining active appliances. In the case no appliances are active, WCCP takes the entire service group
offline and subsequent requests bypass redirection. In addition, WCCPv2 supports MD5 authentication
for the communications between WCCP server and WSA appliances.
Note
In the event the entire service group fails, WCCP automatically bypasses redirection, allowing users to
browse the Internet without the Web controls. In case it is desired to handle a group failure by blocking
all traffic, an outbound ACL may be configured on the Cisco ASA outside interface to permit
HTTP/HTTPS traffic originated from the WSA appliance itself and to block any direct requests from
clients. The ACL may also have to be configured to permit HTTP/HTTPS access from IPS and other
systems requiring such access.
WCCPv2 supports Generic Route Encapsulation (GRE) and Layer-2-based redirection; however, the
Cisco ASA only supports GRE. In addition, WCCP is supported only on the ingress of an interface. The
only topology supported is one where both clients and WSA are reachable from the same interface, and
where the WSA can directly communicate with the clients without going through the Cisco ASA. For
these reasons, the WSA appliance is deployed at the inside segment of the Cisco ASA.
Figure 4-9 illustrates the how WCCP redirection works in conjunction with Cisco ASA.
Figure 4-9
WCCP Redirection
Website.com
Internet
4
2
3
www
1
WSA
227428
5
The following steps describe what takes place in Figure 4-9:
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Step 1
Client’s browser requests connection to http://website.com.
Step 2
Cisco ASA intercepts and redirects HTTP requests over GRE.
Step 3
If content not present in local cache, WSA performs a DNS query on destination domain and checks the
received IP address against URL and reputation rules, and allows/denies request accordantly.
Step 4
WSA fetches content from destination web site.
Step 5
Content is inspected and then delivered directly to the requesting client.
The WSA appliance may also be configured to control and block peer-to-peer file-sharing and Internet
applications such as AOL Messenger, BitTorrent, Skype, Kazaa, etc. The way WSA handles these
applications depends on the TCP port used for transport:
•
Port 80—Applications that use HTTP tunneling on port 80 can be handled by enforcing access
policies within the web proxy configuration. Application access may be restricted based on
applications, URL categories, and objects. Applications are recognized and blocked based on their
user agent pattern, and by the use of regular expressions. The user may also specify categories of
URL to block, including the predefined chat and peer-to-peer categories. Custom URL categories
may also be defined. Peer-to-peer access may also be filtered based on object and MIME
Multipurpose Internet Mail Extensions (MIME) types.
•
Ports other than 80—Applications using ports other than 80 can be handled with the L4TM feature.
L4TM block access to a specific application by preventing access to the server or block of IP
addresses to which the client application must connect.
Note
In the school design, the Cisco ASA is configured to allow only permitted ports (HTTP and HTTPS), so
any connection attempts on other ports should be blocked by the firewall.
Note
The Cisco IPS appliances and modules, and the Cisco ASA (using the modular policy framework), may
also be used to block peer-to-peer file sharing and Internet applications.
The following are the guidelines for implementing a Cisco IronPort WSA appliance with WCCP on a
Cisco ASA:
•
Deploy WSA on the inside of the firewall so that the WSA can communicate with the clients without
going through the firewall.
•
Implement MD5 authentication to protect the communications between the Cisco ASA and the
WSA(s).
•
Configure a redirect-list on the firewall to indicate what traffic needs to be redirected. Make sure the
WSA is always excluded from redirection.
•
Ingress ACL on the firewall takes precedence over WCCP redirection, so make sure the ingress ACL
is configured to allow HTTP and HTTPS traffic from clients and the WSA itself.
•
In an existing proxy environment, deploy the WSA downstream from the existing proxy servers
(closer to the clients).
•
Cisco ASA does not support WCCP IP source address spoofing, therefore any upstream
authentication or access controls based on client IP addresses are not supported. Without IP address
spoofing, requests originating from a client are sourced with the IP address of the Web Proxy, and
not the one of the client.
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Note
•
TCP intercept, authorization, URL filtering, inspect engines, and IPS features do not apply to
redirected flows of traffic served by the WSA cache. Content requested by the WSA is still subject
to all the configured features on the firewall.
•
Configure WSA access policies to block access to applications (AOL Messenger, Yahoo Messenger,
BitTorrent, Kazaa, etc) and URL categories not allowed by the school's Internet access policies.
•
If an out-of-band (OOB) management network is available, use a separate interface for
administration.
WCCP, firewall, and other stateful features usually require traffic symmetry, whereby is traffic in both
directions should flow through the same stateful device. The school architecture is designed with a single
Internet path ensuring traffic symmetry. Care should be taken when implementing active-active firewall
pairs as they may introduce asymmetric paths.
The Layer-4 Traffic Monitor (L4TM) service is deployed independently from the Web Proxy
functionality, and its mission is to monitor network traffic for rogue activity and for any attempts to
bypass port 80. L4TM works by listening to all UDP and TCP traffic and by matching domain names
and IP addresses against entries in its own database tables to determine whether to allow incoming and
outgoing traffic. The L4TM internal database is continuously updated with matched results for IP
addresses and domain names. Additionally, the database table receives periodic updates from the
IronPort update server (https://update-manifests.ironport.com).
The following are the key guidelines when deploying the L4 Traffic Monitor:
•
Determine physical connection—L4TM requires traffic to be directed to the WSA for monitoring.
This can be done by connecting a physical network tap, configuring SPAN port mirroring on a
switch, or using a hub. Network taps forward packets in hardware, while SPAN port mirroring is
generally done in software. On the other hand, SPAN port mirroring can be easily reconfigured,
providing further flexibility.
•
Location—Deploy L4TM in the network where it can see as much traffic as possible before getting
out to the Internet through the firewall. It is important that the L4TM be logically connected after
the proxy ports and before any device that performs network address translation (NAT) on client IP
addresses.
•
Action setting—The default setting for the L4TM is monitor only. Optionally you may configure the
L4TM to monitor and block suspicious traffic. TCP connections are reset with the generating of TCP
resets, while UDP sessions are tear down with ICMP unreachables. The use of L4TM blocking
requires that the L4TM and the Web Proxy to be placed on the same network so that all clients are
accessible on routes that are configured for data traffic.
In the school architecture, L4TM is deployed by setting a SPAN session on the distribution switch to
replicate all TCP and UDP traffic on the links connecting to the inside interface of the firewall. Using
SPAN provides greater flexibility, and inspecting the firewall’s inside links ensures traffic is monitored
before NAT and before being sent out the Internet. The L4TM deployment is shown in Figure 4-10.
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Figure 4-10
L4TM Deployment
All TCP/UDP
Ports
NAT
L4TM - SPAN
www
Web Proxy
Inside
HTTP/HTTPS
Cisco
ASA
227429
Cisco
IronPort
WSA
WCCP
L4TM action is set to monitor only. Because the Internet firewall is configured to block any traffic bound
to the Internet other than HTTP and HTTPS, there is no additional benefit in using L4TM blocking. If
active mitigation is required, consider implementing a Cisco IPS module or appliance in in-line mode.
When deployed in inline mode, the Cisco IPS is placed in the traffic path and is capable of stopping
malicious traffic before it reaches the intended target. In addition, the Cisco IPS provides multiple
configurable response actions including blocking the malicious packet only, blocking the entire session,
or blocking any traffic coming from the offending system.
Configuration steps and examples are included in Chapter 11, “District Office Design.”
Network Access Security and Control
Some of the most vulnerable points of the network are the access edges where students, staff and faculty
connect to the network. With the proliferation of wireless networks, increased use of laptops and smart
mobile devices, the school administration cannot simply rely on physical controls hoping to prevent
unauthorized systems from being plugged into the ports of the access switches. Protection should be
rather embedded into the network infrastructure, leveraging the native security features available in
switches and routers. Furthermore, the network infrastructure should also provide dynamic identity or
role-based access controls for all systems attempting to gain access.
Implementing role-based access controls for users and devices help reduce the potential loss of sensitive
information by enabling schools to verify a user or device identity, privilege level, and security policy
compliance before granting network access. Security policy compliance could consist of requiring
antivirus software, OS updates or patches. Unauthorized, or noncompliant devices can be placed in a
quarantine area where remediation can occur prior to gaining access to the network.
The Schools SRA achieves access security and control by using the following technologies:
•
Catalyst Integrated Security Features (CISF)
•
Cisco NAC Appliance
•
Cisco Identity-Based Network Networking Services (IBNS)
The CISF is a set of native security features available on Cisco Catalyst Switches and designed to protect
the access infrastructure and users from spoofing, man-in-the-middle, DoS and other network-based
attacks. CISF includes features such as private VLANs, port security, DHCP snooping, IP Source Guard,
secure Address Resolution Protocol (ARP) detection, and dynamic ARP inspection (DAI). CISF features
are considered to be part of a security baseline and should be deployed on all access ports.
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In addition to using the CISF features to secure the access ports, access control solutions like IBNS or
NAC appliance may be deployed to control who can access the network and ensure endpoint compliance
with the schools security policies.
The Cisco IBNS solution is a set of Cisco IOS software services designed to enable secure user and host
access to enterprise networks powered by Cisco Catalyst switches and wireless LANs. It provides
standards-based network access control at the access layer by using the 802.1X protocol to secure the
physical ports where end users connect. 802.1X is an IEEE standard for media-level (Layer 2) access
control, offering the capability to permit or deny network connectivity based on the identity of the end
user or device enabling enterprise policy enforcement of all users and hosts, whether managed or
unmanaged. In addition to holistic access-control provided by 802.1X, IBNS also offers device-specific
access-control through MAC-Authentication Bypass (MAB) and user-based access-control through
Web-Auth.
The Cisco Network Admission Control (NAC) Appliance uses the network infrastructure to enforce
security policy compliance on all devices seeking to access network computing resources. With NAC
Appliance, network administrators can authenticate, authorize, evaluate, and remediate wired, wireless,
and remote users and their machines prior to network access. It identifies whether networked devices
such as laptops, IP phones, or game consoles are compliant with your network's security policies and
repairs any vulnerability before permitting access to the network. Noncompliant machines are redirected
into a quarantine area, where remediation occurs at the discretion of the administrator.
The choice of which access control solution to use depends on the security goals and the direction of the
network design. For networks using or moving towards 802.1x-based wired or wireless access and
interested in identity-based access control, Cisco IBNS solution should be considered. For networks
requiring role-based access control using posture assessments to ensure security compliance, Cisco NAC
Appliance should be considered.
The Catalyst Integrated Security Features (CISF), and the Cisco Identity-Based Networking Services
(IBNS) and NAC Appliance access control solutions are discussed in Chapter 9, “Access Layer Security
Design.”
Endpoint Protection
Servers, desktop computers, laptops, printers, and IP phones are examples of the diverse network
endpoints commonly present in School environments. The great variety in hardware types, operating
systems, and applications represents a clear challenge to security. In addition, students and staff may
bring laptops and other portable devices that could also be used outside the school’s premises, potentially
introducing viruses, worms, spyware, and other type of malware.
Properly securing the endpoints requires not only adoption of the appropriate technical controls but also
end-user awareness. While this document focuses on the implementation of the technical controls, the
school’s security strategy must include security awareness campaigns and programs. Students and staff
must be continuously educated on current threats, use best practices, and the security measures needed
for keeping endpoints up-to-date with the latest updates, patches, and fixes.
Following the best practices of Cisco SAFE, the school architecture implements a range of security
controls designed to protect the endpoints. These include host-based Cisco IPS, network-based intrusion
prevention systems, and web and E-mail traffic security.
As Cisco host-based IPS, the architecture leverages the Cisco Security Agent (CSA). CSA takes a
proactive and preventative approach, using behavior-based security to focus on preventing malicious
activity on the host. Malicious activity is detected and blocked, independent of the type of malware,
spyware, adware, or virus affecting the host.
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Once deployed on an endpoint, whenever an application attempts an operation, the agent checks the
operation against the application’s security policy—making a real-time allow or deny decision on the
continuation of that operation and determining whether logging the operation request is appropriate.
Security policies are collections of rules that IT or security administrators assign to protect servers and
desktops, either individually or organization-wide. CSA provides defense-in-depth protection against
spyware and adware by combining security policies that implement distributed firewall, operating
system lockdown and integrity assurance, malicious mobile code protection, and audit-event collection
capabilities in default policies for servers and desktops.
CSAs are centrally managed with the CSA Management Center (CSA-MC), which in the Cisco SAFE
design is placed in a secure segment in the data center. The Management Center (MC) also provides
centralized reporting and global correlation.
For complete details about deploying CSA in a network, refer to the Rapid Deployment Guide for Cisco
Security Agent 6.0 for Desktops at the following URL:
http://www.cisco.com/en/US/prod/collateral/vpndevc/ps5707/ps5057/deployment_guide_c07-501928.
htm
Internet Perimeter Security
Internet Border Router
Whether the Internet border router is managed by the school or the ISP, it must be hardened following
the best practices listed in the Network Foundation Protection section. This includes restricting and
controlling administrative access, protecting the management and control planes, and securing the
dynamic exchange of routing information. In addition, the Internet border router may be leveraged as the
first layer of protection against outside threats. To that end, edge ACLs, uRPF and other filtering
mechanisms may be implemented for anti-spoofing and to block invalid packets.
The following configuration snippet illustrates the structure of an edge ACL applied to the upstream
interface of the Internet border router. The ACL is designed to block invalid packets and to protect the
infrastructure IP addresses from the Internet. The configuration assumes the school is assigned the
198.133.219.0/24 address block, and that the upstream link is configured in the 64.104.10.0/24 subnet.
! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!--- Module 1: Anti-spoofing Denies
!--- These ACEs deny fragments, RFC 1918 space,
!--- invalid source addresses, and spoofs of
!--- internal space (space as an external source).
!
!--- Deny fragments.
access-list 110 deny tcp any 198.133.219.0 0.0.0.255 fragments
access-list 110 deny udp any 198.133.219.0 0.0.0.255 fragments
access-list 110 deny icmp any 198.133.219.0 0.0.0.255 fragments
!--- Deny special-use address sources.
!--- See RFC 3330 for additional special-use addresses.
access-list 110 deny ip host 0.0.0.0 any
access-list 110 deny ip 127.0.0.0 0.255.255.255 any
access-list 110 deny ip 192.0.2.0 0.0.0.255 any
access-list 110 deny ip 224.0.0.0 31.255.255.255 any
!--- Filter RFC 1918 space.
access-list 110 deny ip 10.0.0.0 0.255.255.255 any
access-list 110 deny ip 172.16.0.0 0.15.255.255 any
access-list 110 deny ip 192.168.0.0 0.0.255.255 any
!--- Deny packets spoofing the school’s public addresses
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access-list 110 deny ip 198.133.219.0 0.0.0.255 any
!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!--- Module 2: Explicit Permit
!--- Permit only applications/protocols whose destination
!--- address is part of the infrastructure IP block.
!--- The source of the traffic should be known and authorized.
!
!--- Permit external BGP to peer 64.104.10.113
access-list 110 permit tcp host 64.104.10.114 host 64.104.10.113 eq bgp
access-list 110 permit tcp host 64.104.10.114 eq bgp host 64.104.10.113
!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!--- Module 3: Explicit Deny to Protect Infrastructure
access-list 110 deny ip 64.104.10.0 0.0.0.255 any
!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!--- Module 4: Explicit Permit for Traffic to School’s Public
!--- Subnet.
access-list 110 permit ip any 198.133.219.0 0.0.0.255
!
Note
The 64.104.0.0/16 and 198.133.219.0/24 address blocks used in the examples here provided are reserved
for the exclusive use of Cisco Systems, Inc.
Internet Firewall
The mission of the Internet firewall is to protect the school’s internal resources and data from external
threats, secure the public services provided by the DMZ, and to control user’s traffic to the Internet. The
Schools Service Ready architecture uses a Cisco ASA appliance as illustrated in Figure 4-11.
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Figure 4-11
Internet Edge Firewall
Building B –
Library and
Communication Center
Building C –
Administration and
Data Center
Access
Distribution
Core
Distribution
Building D –
Social Science
and Health
Building E –
Arts and
Technology
Building F –
History and
Geography
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Access
The Cisco ASA is implemented with three interface groups, each one representing a distinct security
domain:
•
Inside—The Inside is the interface connecting to the core/distribution switch that faces the interior
of the network where internal users and resources reside.
•
Outside—Interface connecting to the Internet border router. The router may be managed either by
the school or a service provider.
•
Demilitarized Zone (DMZ)—The DMZ hosts school services that are accessible over the Internet.
These services may include a web portal and E-mail services.
The Internet firewall acts as the primary gateway to the Internet; Therefore, its deployment should be
carefully planned. The following are key aspects to be considered when implementing the firewall:
•
Firewall Hardening and Monitoring
•
Network Address Translation (NAT)
•
Firewall Access Policies
•
Firewall Redundancy
•
Routing
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Firewall Hardening and Monitoring
The Cisco ASA should be hardened in a similar fashion as the infrastructure routers and switches.
According to the Cisco SAFE security best practices, the following is a summary of the measures to be
taken:
•
Implement dedicated management interfaces to the OOB management network.
•
Present legal notification for all access attempts.
•
Use HTTPS and SSH for device access. Limit access to known IP addresses used for administrative
access.
•
Configure AAA for role-based access control and logging. Use a local fallback account in case AAA
server is unreachable.
•
Use NTP to synchronize the time.
•
Use syslog or SNMP to keep track of system status, traffic statistics, and device access information.
•
Authenticate routing neighbors and log neighbor changes.
•
Implement firewall access policies (explained in the Firewall Access Policies).
The Cisco ASA 5510 and higher appliance models come with a dedicated management interface that
should be used whenever possible. Using a dedicated management interface keeps the management
plane of the firewall isolated from threats originating from the data plane. The management interface
should connect to the OBB management network, if one is available.
The following is an example of the configuration of a dedicated management interface.
interface Management0/0
nameif management
security-level 100
ip address 172.26.160.225 255.255.252.0
management-only
!
Note
Any physical interface or logical sub-interface can be configured as a management-only interface using
the management-only command.
It is recommended that a legal notification banner is presented on all interactive sessions to ensure that
users are notified of the security policy being enforced and to which they are subject. The notification
banner should be written in consultation with your legal advisors.
The following example displays the banner after the user logs in:
banner motd UNAUTHORIZED ACCESS TO THIS DEVICE IS PROHIBITED.
banner motd You must have explicit, authorized permission to access or configure this
device.
banner motd Unauthorized attempts and actions to access or use this system may result in
civil and/or criminal penalties.
banner motd All activities performed on this device are logged and monitored.
Management access to the firewall should be restricted to SSH and HTTPS. SSH is needed for CLI
access and HTTPS is needed for the firewall GUI-based management tools such as CSM and ADSM.
Additionally, this access should only be permitted for users authorized to access the firewalls for
management purposes.
The following ASA configuration fragment illustrates the configuration needed to generate a 768 RSA
key pair and enabling SSH and HTTPS access for devices located in the management subnet.
! Generate RSA key pair with a key modulus of 768 bits
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crypto key generate rsa modulus 768
! Save the RSA keys to persistent flash memory
write memory
! enable HTTPS
http server enable
! restrict HTTPS access to the firewall to permitted management stations
http <CSM/ADSM-IP-address> 255.255.255.255 management
! restrict SSH access to the firewall to well-known administrative systems
ssh <admin-host-IP-address> 255.255.255.255 management
! Configure a timeout value for SSH access to 5 minutes
ssh timeout 5
Administrative users accessing the firewalls for management must be authenticated, authorized, and
access should be logged using AAA. The following ASA configuration fragment illustrates the AAA
configurations needed to authenticate, authorize, and log user access to the firewall:
aaa-server tacacs-servers protocol tacacs+
reactivation-mode timed
aaa-server tacacs-servers host <ACS-Server>
key <secure-key>
aaa authentication ssh console tacacs-servers LOCAL
aaa authentication serial console tacacs-servers LOCAL
aaa authentication enable console tacacs-servers LOCAL
aaa authentication http console tacacs-servers LOCAL
aaa authorization command tacacs-servers LOCAL
aaa accounting ssh console tacacs-servers
aaa accounting serial console tacacs-servers
aaa accounting command tacacs-servers
aaa accounting enable console tacacs-servers
aaa authorization exec authentication-server
! define local username and password for local authentication fallback
username admin password <secure-password> encrypted privilege 15
As with the other infrastructure devices in the network, it is important to synchronize the time on the
firewall protecting the management module using NTP.
The following configuration fragment illustrates the NTP configuration needed on an ASA to enable
NTP to an NTP server located in the management network:
ntp
ntp
ntp
ntp
authentication-key 10 md5 *
authenticate
trusted-key 10
server <NTP-Server-address> source management
Syslog and SNMP can be used to keep track of system status, device access, and session activity.
NetFlow Security Event Logging (NSEL), now supported on all Cisco ASA models, may also be used
for the monitoring and reporting of session activity. The following configuration fragment illustrates the
configuration of Syslog.
logging trap informational
logging host management <Syslog-Server-address>
logging enable
The routing protocol running between the Internet firewall and the core/distribution should be secured.
The following ASA configuration fragment illustrates the use of EIGRP MD5 authentication to
authenticate the peering session between the inside firewall interface and the core/distribution switch:
interface Redundant1
nameif inside
security-level 100
ip address 10.125.33.10 255.255.255.0
authentication key eigrp 100 <removed> key-id 1
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authentication mode eigrp 100 md5
Network Address Translation (NAT)
NAT is required because the school typically gets a limited number of public IP addresses. In addition,
NAT helps shield the school’s internal address space from reconnaissance and another malicious activity.
The following illustrates the NAT configuration:
! Static translation for servers residing at DMZ
static (dmz,outside) 198.133.219.10 10.25.34.10 netmask 255.255.255.255
static (dmz,outside) 198.133.219.11 10.25.34.11 netmask 255.255.255.255
static (dmz,outside) 198.133.219.12 10.25.34.12 netmask 255.255.255.255
static (dmz,outside) 198.133.219.13 10.25.34.13 netmask 255.255.255.255
!
! Dynamic Port Address Translation (PAT) for inside hosts going to the Internet
global (outside) 10 interface
nat (inside) 10 10.0.0.0 255.0.0.0
!
Static translation for inside hosts going to the DMZ and vice-versa. The inside IP addresses are visible
to the DMZ.
static (inside,dmz) 10.0.0.0 10.0.0.0 netmask 255.0.0.0
Firewall Access Policies
As previously explained, the Internet firewall should be configured to:
•
Protect school internal resources and data from external threats by preventing incoming access from
the Internet.
•
Protect public resources served by the DMZ by restricting incoming access to the public services
and by limiting outbound access from DMZ resources out to the Internet.
•
Control user's Internet-bound traffic.
Enforcing such policies requires the deployment of ACLs governing what traffic is allowed or prevented
from transiting between interfaces. By default, the Cisco ASA appliance allows traffic from higher to
lower security level interfaces (i.e., from inside to outside). However, due to the sensitivity of school
environments, the school administration may opt to override the default rules with more stringent rules
indicating exactly what ports and protocols are permitted.
It should also be noted that, as the Cisco ASA inspects traffic, it is able to recognize packets belonging
to already established sessions. The stateful inspection engine of the firewall dynamically allows the
returning traffic. Therefore, the firewall ACLs should be constructed to match traffic in the direction in
which it is being initiated. In our sample configurations, ACLs are applied in the ingress direction.
The following are the guidelines and configuration examples of ACLs controlling access and traffic
flows:
•
Ingress Inside
Allow Internet access to student, staff and faculty residing at all school premises for the allowed
ports and protocols. This typically includes HTTP and HTTPS access.
access-list Outbound extended permit tcp 10.0.0.0 255.0.0.0 any eq http
access-list Outbound extended permit tcp 10.0.0.0 255.0.0.0 any eq https
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Allow students, staff, and faculty access to DMZ services such as school web portal, E-mail, and
domain name resolution (HTTP, HTTPS, SMTP, POP, IMAP, and DNS). Note that the previous
entries in the ACL already permit HTTP and HTTPS traffic.
! Allow DNS queries to DNS server
access-list Outbound extended permit udp 10.0.0.0 255.0.0.0
! Allow SMTP, POP3 and IMAP access to DMZ mail server
access-list Outbound extended permit tcp 10.0.0.0 255.0.0.0
access-list Outbound extended permit tcp 10.0.0.0 255.0.0.0
access-list Outbound extended permit tcp 10.0.0.0 255.0.0.0
! Apply ACL to inside interface
access-group Outbound in interface inside
•
host 10.25.34.13 eq domain
host 10.25.34.12 eq smtp
host 10.25.34.12 eq pop3
host 10.25.34.12 eq imap4
Ingress DMZ
Restrict connections initiated from DMZ to the only necessary protocols and sources. This typically
includes DNS queries and zone transfer from DNS server, SMTP from E-mail server, HTTP/SSL
access from the Cisco IronPort ESA for updates, Sensorbase, etc.
! Allow DNS queries and zone transfer from DNS server
access-list DMZ extended permit udp host 10.25.34.13 any eq
access-list DMZ extended permit tcp host 10.25.34.13 any eq
!
! Allow SMTP from Cisco IronPort ESA
access-list DMZ extended permit tcp host 10.25.34.11 any eq
!
! Allow update and SensorBase access to Cisco IronPort ESA
access-list DMZ extended permit tcp host 10.25.34.11 any eq
access-list DMZ extended permit tcp host 10.25.34.11 any eq
!
! Apply ACL to DMZ interface
access-group DMZ in interface dmz
•
domain
domain
smtp
http
https
Ingress Outside
Inbound Internet access should be restricted to the public services provided at the DMZ such as
SMTP, Web, and DNS. Any connection attempts to internal resources and subnets from the Internet
should be blocked. ACLs should be constructed using the servers’ global IP addresses.
! Allow DNS queries and zone transfer to DNS server
access-list Inbound extended permit udp any host 198.133.219.13
access-list Inbound extended permit tcp any host 198.133.219.13
!
! Allow SMTP to Cisco IronPort ESA
access-list Inbound extended permit tcp any host 198.133.219.11
!
! Allow HTTP/HTTPS access to school public web portal
access-list Inbound extended permit tcp any host 198.133.219.10
access-list Inbound extended permit tcp any host 198.133.219.10
!
! Apply ACL to outside interface
access-group Inbound in interface outside
eq domain
eq domain
eq smtp
eq http
eq https
Firewall Redundancy
The Internet perimeter of the school architecture uses a single Cisco ASA appliance configured with
redundant interfaces. The use of redundant interfaces makes the design resilient to link level failures,
representing an affordable option for high availability. In cases where chassis redundancy is desirable,
the school may consider deploying a pair of Cisco ASA appliances configured for stateful failover. Both
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active/active and active/standby failover modes are supported. While stateful failover protects against
chassis failures, it requires the deployment of two identical Cisco ASA appliances and the adjustment of
the topologies around the firewalls, so its deployment should be carefully planned.
This guide explains the use of redundant interfaces. For information on how to configure stateful
failover, refer to the Cisco ASA 5500 Series Adaptive Security Appliances Configuration Guides at the
following URL:
http://www.cisco.com/en/US/products/ps6120/products_installation_and_configuration_guides_list.ht
ml
A Cisco ASA redundant interface is a logical interface that pairs two physical interfaces, called active
and standby interfaces. Under normal operation the active interface is the only one passing traffic. The
active interface uses the IP address defined at the redundant interface, and the MAC address of the first
physical interface associated with the redundant interface. When the active interface fails, the standby
interface becomes active and starts passing traffic. The same IP address and MAC address are maintained
so that traffic is not disrupted. Figure 4-12 illustrates the concept of redundant interface.
Figure 4-12
Cisco
Catalyst
4507
Cisco ASA Redundant Interface
Cisco
Inside ASA
10.125.33.10 5520
Outside
Gi5/3
Gi0/0
Internet
Gi4/4
Gi0/1
Redundant
Interface
227431
VLAN 200
10.125.33.9
The configuration of a redundant interface consists in the configuration of the physical interface
parameters and the logical redundant interface. Physical parameters such as media type, duplex, and
speed are still configured within the physical interface. IP address, interface name, routing protocols,
security level are configured as part of the redundant interface. The following configuration example
corresponds to Figure 4-12.
! Physical interface and Ethernet parameters
interface GigabitEthernet0/0
description Connected to cr24-4507-DO
no nameif
no security-level
no ip address
!
interface GigabitEthernet0/1
description backup to cr24-4507-DO
no nameif
no security-level
no ip address
!
! Defines logical redundant interface associated with physical interfaces. Configures IP
and logical interface parameters.
interface Redundant1
description Connected to cr24-4507-DO
member-interface GigabitEthernet0/0
member-interface GigabitEthernet0/1
nameif inside
security-level 100
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ip address 10.125.33.10 255.255.255.0
authentication key eigrp 100 <removed> key-id 1
authentication mode eigrp 100 md5
!
Routing
An interior gateway protocol, EIGRP in our configuration examples, is used for dynamic routing. The
Internet firewall may participate in routing by learning the internal routes and by injecting a default route
pointing to the Internet. The default route should be removed dynamically if the Internet connection
becomes unavailable.
As part of the school architecture, two different approaches were validated for the injection of the default
route:
•
OSPF—The Cisco ASA appliance learns the default route from the Internet border router using
OSPF. The default route is then redistributed into EIGRP, and from there propagated into the rest of
the internal network.
•
Static Route—The Cisco ASA appliance is configured with a static default route pointing to the
Internet gateway. Object tracking is configured to dynamically remove the default route when the
Internet connection becomes unavailable. The default route is redistributed into EIGRP, and from
there propagated into the rest of the internal network.
Injecting a default route with OSPF requires the configuration of an OSPF process between the Cisco
ASA and the Internet border router, as illustrated in Figure 4-13. If the router is managed by the ISP, the
configuration will require coordination with the service provider. This scenario also requires the default
route to be propagated over OSPF. The actual default route may originate from the Internet border router
itself or somewhere in the ISP network.
Figure 4-13
Cisco ASA OSPF
EIGRP 100
OSPF 200
Cisco
Catalyst
4507
default
Internet
default
227432
VLAN 200
10.125.33.9/24
Cisco
Internet
Inside ASA
Border
10.125.33.10/24 5520
Outside
Router
Gi0/0
Gi5/3
Gi0/2
.1
198.133.219.5/24
Gi0/1
Gi4/4
The following are the guidelines for using OSPF for the injection of a default route:
•
Whenever possible, use MD5 authentication to secure the routing session between the Cisco ASA
and the Internet border router.
•
Since NAT is configured on the Cisco ASA and the inside address space is not visible outside the
firewall, there is no need to redistribute routes from the internal EIGRP into OSPF.
•
Route redistribution from OSPF into the internal EIGRP should be limited to the default route only.
No other routes should be propagated into EIGRP.
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The following configuration snippet illustrates the routing configuration of the Cisco ASA appliance.
The configuration includes the route redistribution from OSPF into EIGRP with the enforcement of a
route-map allowing only the injection of the default route. MD5 authentication is used for OSPF, and the
logging of neighbor status changes is enabled.
! Permit default only
access-list Inbound-Routes standard permit host 0.0.0.0
!
interface GigabitEthernet0/2
ospf message-digest-key 1 md5 <removed>
ospf authentication message-digest
!
route-map Inbound-EIGRP permit 10
match ip address Inbound-Routes
!
router eigrp 100
no auto-summary
network 10.125.33.0 255.255.255.0
passive-interface default
no passive-interface inside
redistribute ospf 200 metric 1000000 2000 255 1 1500 route-map Inbound-EIGRP
!
router ospf 200
network 198.133.219.0 255.255.255.0 area 100
area 100 authentication message-digest
log-adj-changes
!
Note
The hello-interval and dead-interval OSPF timers can be adjusted to detect topological changes faster.
The other validated alternative for the default route injection is the definition of a static default route,
which then can be redistributed into the internal EIGRP process. This is shown in Figure 4-14. This
option does not require the configuration of the Internet border router.
Figure 4-14
Cisco ASA Static Route
EIGRP 100
VLAN 200
10.125.33.9
Cisco
Internet
Inside ASA
Border
10.125.33.10/24 5520
Outside
Router
Gi5/3
Gi0/0
Gi0/2
.1
198.133.219.5/24
Gi0/1
Gi4/4
Internet
default
Object Tracking
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Cisco
Catalyst
4507
It is highly recommended to use object tracking so the default route is removed when the Internet
connection becomes unavailable. Without object tracking, the default route will be removed only if the
outside interface of the appliance goes down. So there is a possibility that the default route may remain
in the routing table even if the Internet border router becomes unavailable. To avoid that problem, the
static default route can be configured with object tracking. This consists in associating the default route
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with a monitoring target. The Cisco ASA appliance monitors the target using ICMP echo requests. If an
echo reply is not received within a specified time period, the object is considered down and the
associated default route is removed from the routing table.
The monitoring target needs to be carefully selected. First, pick one that can receive and respond to
ICMP echo requests sent by the Cisco ASA. Second, it is better to use a persistent network object. In the
configuration example below the Cisco ASA monitors the IP address of the next hop gateway, which
helps identifying if the Internet gateway goes down, but it will not help if the connection is lost upstream.
If available, you may want to monitor a persistent network object located somewhere in the ISP network.
Static route tracking can also be configured for default routes obtained through DHCP or PPPoE.
In the following configuration the IP address of the next hop gateway (198.133.219.1) is used as the
monitoring target. The static default route is then redistributed into EIGRP.
router eigrp 100
no auto-summary
network 10.125.33.0 255.255.255.0
passive-interface default
no passive-interface inside
redistribute static metric 1000000 2000 255 1 1500
!
route outside 0.0.0.0 0.0.0.0 198.133.219.1 1 track 10
!
sla monitor 1
type echo protocol ipIcmpEcho 198.133.219.1 interface outside
sla monitor schedule 1 life forever start-time now
!
track 10 rtr 1 reachability
Note
The frequency and timeout parameters of object tracking can be adjusted to detect topological changes
faster.
Web Security
The Schools Service Ready Architecture implements a Cisco IronPort WSA at the core/distribution layer
of the district office, as illustrated in Figure 4-15. The WSA is located at the inside of the Cisco ASA
acting as the Internet firewall. That ensures that clients and WSA are reachable over the same inside
interface of the firewall, and that the WSA can communicate with them without going through the
firewall. At the same time, deploying the WSA at the core/distribution layer gives complete visibility to
the WSA on the traffic before getting out to the Internet through the firewall.
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Figure 4-15
Core
Distribution
WSA Deployment
Internet Edge
Cisco
Catalyst
4507
Cisco ASA
5520
Inside
Outside
Internet
Border
Router
Internet
SensorBase
Cisco IronPort
WSA S160
227434
www
Following subsections describe the guidelines for the WSA configuration and deployment.
Initial System Setup Wizard
The WSA provides a browser-based system setup wizard that must be executed the first time the
appliance is installed. The System Setup Wizard guides the user through initial system configuration
such as network and security settings. It is critical to note that some of the initial settings cannot be
changed afterwards without resetting the appliance’s configuration to its factory defaults. Therefore,
care should be taken in choosing the right configuration options. Plan not only for the features to be
implemented immediately, but also for what that might be required in the future.
The following are some guidelines when running the System Setup Wizard:
Note
•
Deployment Options—Step 2 of the wizard gives the user the options to enable only L4 Traffic
Monitoring, enable only Secure Web Proxy, or enable both functions. Select enable both Secure Web
Proxy and L4 Traffic Monitor if you plan to use both functions.
•
Proxy Mode—If the Secure Web Proxy function has been enabled, Step 2 of the wizard requires the
user to choose between Forward and Transparent mode. It should be noted that a WSA appliance
initially configured in Transparent mode can still be configured as a Forward Web Proxy, per
contrary, the Transparent Web Proxy function is not available if the appliance is configured in
Forward mode. Therefore, select Forward mode only if you certain that the Transparent mode will
never be required.
The deployment and proxy mode options cannot be changed after the initial configuration without
resetting the WSA appliance to its factory defaults. Plan your configuration carefully.
Interface and Network Configuration
The following need to be configured as part of the initial setup of the WSA appliance:
Step 1
Configuring network interfaces
Step 2
Adding routes
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Step 3
Configuring DNS
Step 4
Setting time
Step 5
Working with upstream proxy (if present)
These settings are configured as part of an initial setup using the System Setup Wizard, but can be later
modified by using the WSA Web-based GUI.
Configuring Network Interfaces
Independently from the model, all Cisco IronPort WSA appliances are equipped with six Ethernet
interfaces as shown in Figure 4-16.
Figure 4-16
WSA Interfaces
Use the M1 port for administering
the appliance.
Use the “P” ports for the Web Proxy.
227435
Use the “T” ports for the L4 Traffic Monitor.
The WSA interfaces are grouped for the following functions:
•
Management—Interfaces M1 and M2 are out-of-band (OOB) management interfaces. However,
only M1 is enabled. In the school architecture, interface M1 connects to the out-of-band
management network. Interface M1 can optionally be used to handle data traffic in case the school
does not have an out-band management network.
•
Web Proxy—Interfaces P1 and P2 are Web Proxy interfaces used for data traffic. Only the P1
interface is used in the school architecture. P1 connects to the inside subnet of the firewall.
•
L4 Traffic Monitor (L4TM)—T1 and T2 are the L4TM interfaces. The school design uses only the
T1 interfaces. The T1 interface connects to a core/distribution switch port configured as the
destination of the SPAN session used to capture traffic bound to the Internet.
Figure 4-17 illustrates the network topology around the WSA used in the Cisco validation lab.
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Figure 4-17
Cisco
IronPort
WSA
www
WSA Network Topology
T1 SPAN
P1
10.125.33.8
Cisco
Catalyst
4507
Gi6/3
Gi7/3
VLAN 200
10.125.33.9
Cisco
Inside ASA
10.125.33.10 5520
Outside
Gi5/3
Gi0/0
Internet
Gi4/4
Gi0/1
M1
172.26.191.105
SP Managed
MetroE Core
227436
OOB
Management
Figure 4-18 illustrate the IP address and hostname configurations for the interfaces used. In this case, an
out-of-band management network is used; therefore the M1 port is configured with an IP address in the
management subnet. In addition, the WSA is configured to maintain a separate routing instance for the
M1 management interface. This allows the definition of a default route for management traffic separate
from the default route used for data traffic.
Figure 4-18
WSA Interface Configuration
Adding Routes
A default route is defined for management traffic pointing to the OOB management default gateway
(172.26.191.1). A separate default route is defined for the data traffic pointing to the inside IP address
of the firewall (10.125.33.10). As all internal networks are reachable throughout the core/distribution
switch, a route to 10.0.0.0/8 is defined pointing to the switch IP address (10.125.33.9) to allow the WSA
to communicate with the clients directly without having to go to the firewall first. These settings are
illustrated in Figure 4-19.
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Figure 4-19
WSA Route Configuration
Configuring DNS
The initial setup requires the configuration of a host name for the WSA appliance, and listing the DNS
servers. Figure 4-20 shows the DNS configuration.
Figure 4-20
WSA DNS Configuration
Time Settings
Time synchronization is critical for forensic analysis and troubleshooting, therefore enabling NTP is
highly recommended. Figure 4-21 shows how the WSA is configured to synchronize its clock with an
NTP server located on the OOB management network.
Figure 4-21
WSA NTP Configuration
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Working with Upstream Proxies
If Internet access is provided by an upstream proxy, then the WSA must be configured to use the proxy
for component updates and system upgrades. This is illustrated in Figure 4-22 and Figure 4-23.
Figure 4-22
WSA Upgrade Settings
Figure 4-23
WSA Component Updates
WCCP Transparent Web Proxy
The configuration of the WCCP Transparent Web Proxy includes the following:
Step 1
Defining WSA WCCP Service Group
Step 2
Enabling WSA Transparent Redirection
Step 3
Enabling WCCP redirection on the Cisco ASA
Step 4
Enabling WSA HTTPS scanning
Step 5
Working with upstream proxy (if present)
Defining WSA WCCP Service Group
Web Proxy settings are configured as part of an initial setup using the System Setup Wizard and can be
later modified with the WSA Web-based GUI. The Web Proxy setting include the following:
•
HTTP Ports to Proxy—List the ports to be proxied. Default is 80 and 3128.
•
Caching—Defines whether or not the WSA should cache response and requests. Caching helps
reduce latency and the load on the Internet links. Default is enabled.
•
IP Spoofing — Defines whether or not the Web Proxy should spoof IP addresses when forwarding
requests to upstream proxies and servers. The Cisco ASA does not support source address spoofing.
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Figure 4-24 illustrates the Web Proxy settings.
Figure 4-24
WSA Proxy Settings
Enabling WSA Transparent Redirection
Configuring WCCP Transparent Redirection requires the definition of a WCCP service profile in the
WSA. If redirecting HTTP and HTTPS, define a dynamic service ID to be used with the Cisco ASA. Use
MD5 authentication to protect the WCCP communication between the WSA and Cisco ASA.
Figure 4-25 shows an example.
Figure 4-25
WSA Transparent Proxy
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Enabling WCCP Redirection on Cisco ASA
The configuration of WCCP on the Cisco ASA appliance requires:
•
A group-list indicating the IP addresses of the appliances member of the service group. In the
example provided below the group-list is called wsa-farm.
•
A redirect-list indicating the ports and subnets of traffic to be redirected. In the example, the ACL
named proxylist is configured to redirect any HTTP and HTTPS traffic coming from the 10.0.0.0/8
subnet. It is critical to ensure traffic from the WSA(s) bypasses redirection. To that end, add an entry
to the redirect-list explicitly denying traffic sourced from the WSA(s).
•
WCCP service indicating the service ID. Make sure you use the same ID as defined on the WSAs.
Use a password for MD5 authentication.
•
Enabling WCCP redirection on an interface. Apply the WCCP service on the inside interface of the
Cisco ASA.
Cisco ASA WCCP configuration example:
! Group-list defining the IP addresses of all WSAs
access-list wsa-farm extended permit ip host 10.125.33.8 any
!
! Redirect-list defining what ports and hosts/subnets should
access-list proxylist extended deny ip host 10.125.33.8 any
access-list proxylist extended permit tcp 10.0.0.0 255.0.0.0
access-list proxylist extended permit tcp 10.0.0.0 255.0.0.0
!
! WCCP service
wccp 10 redirect-list proxylist group-list wsa-farm password
!
! Applies WCCP on an interface
wccp interface inside 10 redirect in
be redirected
any eq www
any eq https
cisco
The WCCP connection status and configuration can be monitored on the Cisco ASA with the show wccp
command. An example is provided below:
cr26-asa5520-do# show wccp
Global WCCP information:
Router information:
Router Identifier:
Protocol Version:
Service Identifier: 10
Number of Cache Engines:
Number of routers:
Total Packets Redirected:
Redirect access-list:
Total Connections Denied Redirect:
Total Packets Unassigned:
Group access-list:
Total Messages Denied to Group:
Total Authentication failures:
Total Bypassed Packets Received:
cr26-asa5520-do#
198.133.219.5
2.0
1
1
428617
proxylist
0
4
wsa-farm
0
0
0
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Enabling WSA HTTPS Scanning
To monitor and decrypt HTTPS traffic, you must enable HTTPS scanning on the WSA. The HTTPS
Proxy configuration is illustrated in Figure 4-26.
Figure 4-26
WSA HTTPS Proxy
Working with Upstream Proxies
In case Internet traffic is handled by one or more upstream proxies, follow these guidelines:
•
Add an Upstream Proxy Group
•
Define a routing policy to direct traffic to the upstream proxies
The Upstream Proxy Group lists the IP addresses or domain names of the proxies to be used for traffic
sent to the Internet. When multiple proxies are available, the WSA can be configured for failover or load
balancing.
The following are the options available:
•
None (failover)—The first proxy in the list is used. If one proxy cannot be reached, the Web Proxy
attempts to connect to the next one in the list.
•
Fewest connections—Transactions are directed to the proxy servicing the fewest number of
connections.
•
Hash-based—Requests are distributed using a hush function. The function uses the proxy ID and
URL as inputs so that requests for the same URL are always directed to the same upstream proxy.
•
Least recently used—Transactions are directed to the proxy that least recently received a transaction
if all proxies are currently active.
•
Round robin—The Web Proxy cycles transactions equally among all proxies in the group in the
listed order.
Figure 4-27 illustrates the upstream proxy group configuration. Two upstream proxies are used, and
transactions are forwarded to the proxy servicing the fewest number of connections.
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Figure 4-27
WSA Upstream Proxy Group
Next, a routing rule needs to be defined to indicate when and how to direct transactions to the upstream
proxy group. Use the Global Routing Policy if all traffic is to be handled by the upstream proxies. If no
proxies are present, then leave the routing destination of the Global Routing Policy configured as Direct
Connection. Figure 4-28 presents an example where all traffic is directed to the proxies in the
Upstream-Lab_proxy group.
Figure 4-28
WSA Routing Policies
Web Access Policies
The access policies define how the Web Proxy handles HTTP requests and decrypted HTTPS
connections for network users. By configuring access policies the school can control what Internet
applications (instant messaging clients, peer-to-peer file-sharing, web browsers, Internet phone services,
etc.) and URL categories students, staff and faculty may access. In addition, access policies can be used
to block file downloads based on file characteristics, such as file size and file type.
The WSA comes with a default Global Policy that applies to all users. However, multiple policies can
be defined when different policies need to be applied to different group of users. Figure 4-29 shows the
global policy.
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Figure 4-29
Global Access Policy
URL categories corresponding to content inappropriate for minors should be blocked in compliance with
the school’s Internet access policies. Figure 4-30 provides an example on how the “Adult/Sexually
Explicit” category is blocked.
Figure 4-30
URL Categories
Layer-4 Traffic Monitoring
(L4TM)
L4TM can be implemented in the school environment to identify rogue traffic across all network ports
and detect malware attempts to bypass port 80. Additionally, L4TM is capable of identifying internal
clients with malware and that attempt to phone-home across non-standard ports and protocols.
Implementing L4TM requires the following:
Step 1
Configuring L4TM interfaces
Step 2
Configuring WSA L4TM global settings
Step 3
Configuring traffic monitoring
Configuring L4TM Interfaces
The wiring type depends on how traffic is directed to the WSA appliance. Network taps and SPAN can
be either configured in simplex or duplex mode. If using a hub, only duplex mode can be used. The
wiring type configuration is typically done during the initial setup as described earlier in this chapter.
Figure 4-31 show the wiring options.
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Figure 4-31
L4TM Wiring Type
Configuring WSA L4TM Global Settings
The ports to be monitored can be specified in the L4TM Global Settings. Options are:
Note
•
All ports—Monitors all 65535 TCP ports for rogue activity.
•
All ports except proxy ports—Monitors all TCP ports except HTTP and HTTPS proxy ports.
The Cisco ASA in the Internet perimeter is configured to allow only permitted ports, so any connection
attempts on rogue ports should be blocked by the firewall.
Figure 4-32 shows the options.
Figure 4-32
L4TM Global Settings
Configuring Traffic Monitoring
While a hub or a network tap could be used, using SPAN port mirroring provides the greatest flexibility.
SPAN allows the monitoring of port traffic based on VLANs or source interfaces and it can easily be
reconfigured.
The following is a configuration example of SPAN to replicate traffic:
! Enables port mirroring on the switch ports connecting to the firewall inside interfaces
monitor session 10 source interface Gi4/4
monitor session 10 source interface Gi5/3
!
! Sets the interface connecting to the WSA as the destination
monitor session 10 destination interface Gi6/3
The SPAN configuration can be seen on the switch with the show monitor session command.
Activity monitored by the L4TM feature can be seen in the L4 Traffic Monitor page of the WSA
web-based GUI. Figure 4-33 shows client activity with a website known to be the source of malware.
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Figure 4-33
L4 Traffic Monitor
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5
Wireless LAN Design
Cisco Unified Wireless Network Architecture
WLANs in the schools have emerged as one of the most effective means for connecting to a network,
given the mobility of students and staff. The Cisco Unified Wireless Network (CUWN) is a unified wired
and wireless network solution that addresses the wireless network security, deployment, management,
and control aspects of deploying a wireless network. It combines the best elements of wireless and wired
networking to deliver secure, scalable wireless networks with a low total cost of ownership.
Figure 5-1 shows a high-level topology of the CUWN architecture, which includes Lightweight Access
Point Protocol (LWAPP) access points (LAPs), mesh LWAPP APs (MAPs), the Wireless Control
System (WCS), and the Wireless LAN Controller (WLC); alternate WLC platforms include the Wireless
LAN Controller Module (WLCM) or Wireless Services Module (WiSM). The Cisco Access Control
Server (ACS) and its Authentication, Authorization, and Accounting (AAA) features complete the
solution by providing RADIUS services in support of wireless user authentication and authorization.
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Figure 5-1
Cisco Unified Wireless Network Architecture Overview
Cisco Catalyst
3750G Integrated
Cisco WCS
Wireless LAN
Navigator
Controller
Browser Based
W
Cisco Wireless
Control System
(WCS)
Cisco Wireless
LAN Controller
Module (WLCM)
Cisco
WCS
Cisco
WCS
Cisco Wireless
LAN Controller
N
S
E
Cisco
Mobile
Services
Engine
Third Party
Integrated
Applications:
E911, Asset
Tracking, ERP,
Workflow
Automation
Cisco Aironet
Wireless Bridge
Cisco Catalyst 6500
Series Wireless
Services Module
(WiSM)
Cisco Aironet
Lightweight
Access Points
(802.11a/b/g
and 802.11n)
Chokepoint
125 kHz
Cisco
Compatible
Client
Devices
Cisco Aironet
Wireless LAN
Client Adapters
Cisco Aironet
1500 Series
Lightweight
Outdoor Mesh
Access Points
225263
Cisco
Compatible
Wi-Fi Tags
The CUWN network is composed of two key elements: Wireless LAN Controllers (WLCs) and Access
Points (APs). These form the core of the Wireless LAN system, where the APs provide the radio
connection between wireless clients and the network, and the WLCs provide network.
Figure 5-2 illustrates one of the primary features of the architecture: how Lightweight Access Point
Protocol (LWAPP) or Control and Provisioning of Wireless Access Points (CAPWAP) access points
(LAPs) use the LWAPP/CAPWAP protocol to communicate with and tunnel traffic to a WLC.
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Note
CUWN is migrating from the LWAPP protocol to CAPWAP, and the WLC software version in the
Schools SRA uses CAPWAP. The fundamentals of the architecture and operation are the same.
Documents discussing the LWAPP architecture operation and behavior are still valid for CAPWAP, apart
from the UDP port numbers. For the purposes of this document and other documents referring to LWAPP,
the Cisco CAPWAP implementation can be considered as a superset of LWAPP features and behavior.
Figure 5-2
LAP and WLC Connection
AP
LWAPP
AP
LWAPP
Network
LWAP
P/CAP
WAP
WLC
PWAP
LWAPP/CA
AP
AP
LW
227453
LWAPP
AP
PW
A
P/C
LWAPP/CAPWAP has three primary functions:
•
Control and management of the LAP
•
Tunneling of WLAN client traffic to the WLC
•
Collection of 802.11 data for the management of the Cisco Unified Wireless System
LWAPP Features
The easier a system is to deploy and manage, the easier it will be to manage the security associated with
that system. Early implementers of WLAN systems that used “fat” APs (autonomous or intelligent APs)
found that the implementation and configuration of such APs was the equivalent of deploying and
managing hundreds of individual firewalls, each requiring constant attention to ensure correct firmware,
configuration, and safeguarding. Even worse, APs are often deployed in physically unsecured areas
where theft of an AP could result in someone accessing its configuration to gain information to aid in
some other form of malicious activity.
LWAPP addresses deployment, configuration, and physical security issues by doing the following:
•
Removing direct user interaction and management of the AP. Instead, the AP is managed by the
WLC through its LWAPP connection. This moves the configuration and firmware functions to the
WLC, which can be further centralized through the use of the WCS.
•
Having the AP download its configuration from the WLC, and be automatically updated when
configuration changes occur on the WLC.
•
Having the AP synchronize its firmware with its WLC, ensuring that the AP is always running the
correct software version.
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•
Storing sensitive configuration data at the WLC, and storing only IP address information on the AP.
In this way, if the AP is physically compromised, there is no configuration information resident in
NVRAM that can be used to perform further malicious activity.
•
Mutually authenticating LAPs to WLCs, and AES encrypting the LWAPP control channel.
In addition to the improvements in physical security, firmware, and configuration management offered
by LWAPP, the tunneling of WLAN traffic in an LWAPP-based architecture improves the ease of
deployment without compromising the overall security of the solution. LAPs that support multiple
WLAN VLANs can be deployed on access-layer switches without requiring dot1q trunking or adding
additional client subnets at the access switches. All WLAN client traffic is tunneled to centralized
locations (where the WLC resides), making it simpler to implement enterprise-wide WLAN access and
security policies.
Schools SRA Architecture
Figure 5-3 shows a simple schematic of the CUWN integration into the schools SRA. The key features
of the CUWN integration is the use of a WLC at each school, with the management function (WCS)
located at the district office. If context-aware services are implemented, the Cisco Mobility Services
Engine (MSE) may be placed at the school; for smaller schools, an MSE at the district office may provide
a centralized service.
The standalone WLCs used in this design support AP capacities from 12 to 250 APs per WLC, and
multiple WLCs may be deployed at the same school if more than 250 APs are required or if a load
sharing or higher availability WLAN solution is required. An alternate higher availability solution is to
use a WLC at the district office as a backup WLC for the school’s WLCs. This is known as an N+1
solution, where a district office WLC maintains sufficient capacity to support the APs of any individual
school site.
A similar principle to N+1 is used to provide high availability for the AAA service provided by the Cisco
ACS server. Each school will have a local ACS server to provide AAA services, and use the district office
ACS server as its secondary AAA server.
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Figure 5-3
High level view of the CUWN SRA Integration
ACS
MSE
W
N
S
WCS
E
WLC
MAN
District Office
ACS
W
N
S
ACS
E
MSE
WLC
WLC
Cisco Catalyst 4500 School
227454
Cisco Catalyst 3750 School
Management
Each of the WLCs has both a CLI and web interface to provide WLAN configuration and management
features, but for a complete lifecycle management solution, the Cisco Wireless Control System (WCS)
is needed. The WCS supports the delivery of high-performance applications and mission-critical
solutions that simplify business operations and improve productivity. This comprehensive platform
scales to meet the needs of small, midsize, and large-scale wireless LANs across local, remote, national,
and international locations. The WCS gives IT managers immediate access to the tools they need, when
they need them, to more efficiently implement and maintain new or expanding WLANs—all from a
centralized location requiring minimal IT staffing. Operational costs are significantly reduced through
the Cisco WCS’s intuitive GUI, simplified ease-of-use, and built-in tools that deliver improved IT
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efficiency, lowered IT training costs, and minimized IT staffing requirements, even as the network
grows. Cisco WCS lowers operational costs by incorporating the full breadth of management
requirements, from radio frequency, to controllers services, and into a single unified platform.
The Cisco WCS scales to manage hundreds of Cisco wireless LAN controllers, which in turn can manage
thousands of Cisco Aironet® access points including the next-generation Cisco Aironet 1140 and 1250
Series 802.11n access points. For large-scale indoor and outdoor deployments, Cisco WCS Navigator
can be included to simultaneously support up to 20 Cisco WCS platforms and 30,000 Cisco access
points. Adding mobility services such as context-aware software and adaptive wireless intrusion
prevention systems (wIPS) is simplified through Cisco WCS integration with the Cisco MSE.
Designing a wireless LAN that effectively supports business-critical data, voice, and video services is
simplified with the Cisco WCS suite of built-in planning and design tools. Figure 5-4 shows an example
of the simplified Wireless LAN Planning and Design Cisco WCS planning and design tools simplify the
process of defining access point placement and determining access point coverage areas for standard and
irregularly shaped buildings. These tools give IT administrators clear visibility into the radio frequency
(RF) environment. They make it easier to visualize the ideal RF environment, anticipate future coverage
needs, and assess wireless LAN behavior. They help IT administrators reduce, and in many cases
eliminate, improper RF designs and coverage problems that can lead to end-user trouble
tickets.Specialized Cisco WCS planning tools enable real-time assessment of the WLAN's readiness to
support voice-over-WLAN (VoWLAN) and context-aware (location) services. VoWLAN services
support single and dual-mode Wi-Fi-enabled phones. Context-aware services use Cisco's patent pending
“RF fingerprinting” technology to locate, track, and manage Wi-Fi-enabled devices and their contextual
information in conjunction with Cisco MSE.
Figure 5-4
WCS planning tools
Getting the WLAN up and running quickly and cost-effectively to meet end-user needs is streamlined
with the broad array of Cisco WCS integrated configuration templates. These easy-to-use templates and
deployment tools help IT managers provision and configure the wireless LAN to expressly deliver the
services that their business requires. Figure 5-5 shows an example of the Flexible Deployment Tools and
Configuration Templates available through an easy-to-use interface, make it simple to apply common
configurations across one or more wireless LAN controllers, regardless of their location in the
network—whether on the same LAN as Cisco WCS, on separate routed subnets, or across a wide-area
connection. At the click of a button, IT administrators can streamline even the most complex controller
configurations, updates, and scheduling across the entire wireless network. Auto-provisioning access
points is just as simple, with easy-to-use templates that support customized configuration of single or
multiple access points.
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Figure 5-5
WCS Deployment Templates
Cisco WCS is the ideal management platform for monitoring the entire WLAN to maintain robust
performance and deliver an optimal wireless experience to mobile end users. Cisco WCS centralized
interface makes it easy to access information where it is needed, when it is needed, on demand or as
scheduled. Figure 5-6 shows an example of the Customizable Dashboard and Easy-to-Use Web-Based
Interface Cisco WCS easy-to-use graphical displays serve as a starting point for maintenance, security,
troubleshooting, and future capacity planning activities. Quick access to actionable data about healthy
and unhealthy events occurring on the network is available from a variety of entry points, making Cisco
WCS vital to ongoing network operations.The ever-present alarm summary in the Cisco WCS simplifies
access to critical information, faults, and alarms based on their severity. Detecting, locating, and
containing unauthorized (rogue) devices is fully supported when location services are enabled.
Figure 5-7 shows an example of the Ever-Present Alarm Summary and Simplified Rogue Device
Detection and Location.
Figure 5-6
WCS Monitoring Dashboard
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Figure 5-7
WCS Alarm Panels
The integrated workflow and expansive array of troubleshooting tools in the Cisco WCS help IT
administrators quickly identify, isolate, and resolve problems across all components of the Cisco Unified
Wireless Network. Cisco WCS supports rapid troubleshooting of any size WLAN with minimal IT
staffing. Figure 5-8 shows an example of the Integrated Workflows and Troubleshooting Tools. Cisco
WCS makes it easy to quickly assess service disruptions, receive notices about performance degradation,
research resolutions, and take action to remedy nonoptimal situations. Integrated workflows support
seamless linkage between all tools, alarms, alerts, searches, and reports for all infrastructure components
and client devices.A variety of tools work together to help IT administrators understand the operational
nuances occurring on the WLAN and discover nonoptimal events occurring outside baseline parameters
such as client connection or roaming problems. The ever-present search tool in Cisco WCS facilitates
cross-network access to real-time and historic information about devices and assets located anywhere in
the wireless network. A built-in client troubleshooting tool provides a step-by-step method to analyze
problems for all client devices. Cisco CleanAirsupports finding, classifying, and correlating sources of
interference from Wi-Fi and non-Wi-Fi sources such as Bluetooth devices and cordless phones.
Figure 5-8
WCS Troubleshooting Tools
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Cisco WCS includes customizable reporting that assists IT teams in more effectively managing,
maintaining, and evolving the wireless LAN to meet ongoing business and operations requirements.
Flexible reports provide access to the right data, at the right time, in a format to meet any requirement.
Figure 5-9 shows an example of the Customizable Reports Meet Any Requirement. An extensive variety
of reports is available to help IT managers stay on top of network trends, maintain network control, audit
operations, and quickly address changing business and end-user requirements. Reports are customizable
based on user-defined parameters. Detailed analysis of what is going on, where and when in the network,
as well as capacity planning, is simplified by collecting data from several reports and analyzing trends
to understand how the WLAN has changed over time. Understanding WLAN trends makes it easier to
plan for future enhancements and growth.
Figure 5-9
WCS Customizable Reports
Connection to the Schools SRA Network
Figure 5-10 and Figure 5-11 show the school switch to WLC physical connection in more detail, a key
feature in of the WLC interface is its direct connection to the core distribution switch via a port channel
interface. This uses multiple Gigabit Ethernet connections from the WLC to the core/distribution switch.
These Gigabit Ethernet connections are to different line cards on switches or line card to ensure that a
single switch or line card failure does not result in the loss of the WLC connection to the school network.
The switch feature to achieve this is the same switch feature used for the Ether Channel connections
between switches in the Schools SRA. The WLC feature is called link aggregation (LAG). LAG is
disabled by default on the WLC and requires a WLC reboot to be enabled. This allows the WLC to use
the same port channel configuration as the access switches when connecting to the core/distribution
switch.
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Figure 5-10
4500 School Switch WLC Physical Connection
ACS
W
N
S
E
MSE
227461
WLC
Figure 5-11
750 School Switch WLC Physical Connection
ACS
227462
WLC
The WLC connects to the switch via a 802.1Q trunk connection, as shown in Figure 5-12, and multiple
SVIs need to be configured on the switch to support the CUWN implementation. The key SVIs are an
SVI for the management and AP manager interface of the WLC, and the SVIs for each of the different
WLANs implemented on the WLC; there is not always a one-to-one relationship between SVIs and
WLANs, but in most simple WLAN deployments this is the case.
Switch WLC Layer-2 Connection
Trunk
227463
Figure 5-12
Figure 5-13 shows an example of the interface configuration summary on school WLC. The key
interfaces of interest are ap-manger, manager, and wlan data1, wlan data2, and wlan voice1 interfaces.
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The server port is an out-of-band management interface not used in this design guide. The virtual
interface and its interface address are used to assist in the provisioning of seamless mobility. The virtual
interface is assigned an address during the initial configuration of the WLC and this address is typically
1.1.1.1 for all controllers.
Figure 5-13
WLC Interface Example
Figure 5-14 shows the mapping of a particular WLAN SSID to a defined interface. A WLAN can be
mapped to the management interface (this is normally not recommended), or any dynamic interface.
Figure 5-14
WLAN Example
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RF Groups and Mobility Groups
Part of a WLCs role is to manage the RF network in its area, and to provide mobility services to WLCs
in its network. To define the area of the RF network that you are interested in managing, use an RF group
name; to define the mobility services domain, use a mobility group. The details of RF groups and
mobility groups are beyond the scope of this design guide, but the key point for the design is that the RF
network area and the mobility services domain will typically be a single school campus, and only WLCs
that are at the same school should have the same RF group name or mobility group name. Figure 5-15
shows an example of the RF and mobility group configuration on the controllers. Each school campus
can be given a different RF group and mobility group as the WLCs are different schools and are not
expected to be in the same RF group or mobility group.
Figure 5-15
Mobility Groups and RF Groups Example
A school with only one WLC will have a mobility group with only its own details in the mobility group.
If there is more than one WLC at the school, then the mobility group configuration will contain both
WLCs.
Figure 5-16 shows the single WLAN example and Figure 5-17 shows a multiple WLC example. If there
is only one WLC, the mobility group information is automatically populated. Additional WLCs must
have the MAC address and management IP address added manually.
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Figure 5-16
Mobility Groups for a Single WLC
Figure 5-17
Mobility Groups for a Multiple WLCs
Example WLAN Configurations
In a typical school WLAN environment, it is expected that there be multiple WLANs (SSIDs) serving
different purposes and different client groups. This section addresses the examples of what would be
considered typical WLAN examples.
•
A secured data WLAN network that uses 802.1X/EAP to provide AAA functionality and
dynamically generated per-user, per-session encryption key.
•
A secured VoWLAN network that also uses 802.1X/EAP to provide AAA functionality and
optimized for voice.
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•
An open unencrypted WLAN for access to a WLAN network for unmanaged clients such as student
laptops, iPod, and iPhones.
For ease of administration and support for users who visit multiple schools, the WLAN SSIDs should be
the same for each school in the district. In addition, the SSIDs should be broadcast and have meaningful
names.
Secured Staff WLAN
Figure 5-18 shows the general WLAN configuration tab for the secured data WLAN network. The key
point shown are the security policy that has been set under the security tab and the WLC interface that
the WLAN has been mapped to. The security configuration recommended is to use WPA2 with
802.1X+CCKM. Most WLAN should now support WPA2, and CCKM has been added to 802.1X as it
provides a faster roaming for WLAN clients. This is for clients that support CCKM, while using the
AAA features of 802.1X/AP to secure the WLAN connection.
Figure 5-18
General Configuration for Secured WLAN
Figure 5-19 shows the QoS configuration for the secured data WLAN; in this case, the QoS profile is set
to Silver, which is best effort setting. The WMM policy is set to disabled, as disabled WMM is the
equivalent of best effort. The primary role of WMM is to give higher priority to voice and video traffic
over the WLAN. Unless the school is planning to deliver interactive voice and video applications to their
WLAN data clients, WMM can remain disabled.
Note
802.11n standard requires WMM be enabled and, therefore, WMM must be enabled on all WLANs in
the 802.11n deployments. In this case, the WMM policy would be set to allowed.
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Figure 5-19
Secured Staff WLAN QoS
Figure 5-20 shows the secured data WLAN advanced configuration. The only change from the default
settings on the tab is enabling the DHCP address assignment required feature. Typically, WLAN mobile
clients use DHCP, and any statically configured client runs the risk of introducing an address duplication
issue.
Figure 5-20
Secured Staff Advanced Configuration
Secured VoWLAN
Figure 5-21 shows the General Tab of the voice over WLAN (VoWLAN). The primary difference
between this WLAN and the secured data WLAN is that the security policy is WPA with CCKM,
because this is the optimum security configuration for the Cisco 7921G and 7925G. The other difference
is that the radio policy has been set for 802.11a only.
The use of 802.11a for the VoWLAN will depend on a number of factors, but the Cisco 7921G and
7925G are dual-band phones, and can use both bands but do not roam between bands. This means that
once the handset associates with a network in one band, it will not leave that band while call quality is
maintained. Keeping the VoWLAN handsets in the 802.11a band will ensure that the 2.4GHz band
remains available for other client devices. Whether this is a viable option for a school depends on the
required call capacity of the school’s WLAN and the type of AP network that has been deployed.
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Figure 5-21
VoWLAN General Configuration
Figure 5-22 shows the QoS Tab for the VoWLAN. In this WLAN configuration, WMM is required (both
the 7921G and 7921G) support WMM, and WMM will give voice traffic priority over other WLAN
traffic on the network. The QoS profile is set to Platinum to ensure that the QoS classification is
appropriate for voice. The QoS profile controls the maximum classification value for both the WLAN
frames and LWAPP packets.
Figure 5-22
VoWLAN QoS Configuration
The Advanced Tab for the VoWLAN is the secured data WLAN. There is an option for VoIP snooping
and reporting, but this option pertains only to a particular type of SIP and is not applicable to the CIsco
7921G and 7925G handsets.
To protect VoIP call quality, the WLC can perform call admission control (CAC) to prevent VoWLAN
calls being added to an access point that cannot take any additional VoWLAN calls without
compromising call quality. An example of the CAC configuration page is shown in Figure 5-23.
Note
There is a separate CAC page for each RF band.
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Figure 5-23
VoWLAN Call Admission Control
The CUWN prioritizes traffic based upon the QoS profiles applied to each WLAN, but it does not change
the IP QoS classification (DSCP) of the client traffic carried by the CUWN. This means that client traffic
that leaves the CUWN may need to be reclassified based upon the network policy. There are two ways
of achieving this.
1.
Applying policy at each of the network SVIs that connect the WLC to the network.
2.
Learning the QoS policy that was applied within the CUWN as this should be in alignment with the
network policy.
The second method is preferable as it requires less configuration and maintenance of the policy; the
policy only needs to be maintained upon WLCs, and not open the WLCs and the connected switch. To
achieve this, the Wired Protocol in the QoS profiles (Platinum, Gold, Sliver, and Bronze) must be set to
802.1p and all other settings may remain as default. This configures the WLC to set the 802.1p marking
of the frames sent from the WLC to reflect QoS policy on that WLAN. For example, the IP packet was
from a Platinum WLAN and had a DSCP value of EF, the WLC would use a CoS value of 5 in the frame
header. If the same packet had been on a Silver WLAN, the CoS value would be 0. Therefore, if the WLC
is connected to switch network that is configured to trust CoS and maintains a translation table between
CoS and DSCP for its network, the translation between CUWN policy and network policy will occur
automatically. See Figure 5-24.
For a further information on WLAN QoS, refer to the Voice over WLAN Design Guide at the following
URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/vowlan/41dg/vowlan41dg-book.html
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Figure 5-24
Controller QoS Profiles
Web Authenticated Student Access
In many situations, it is not possible to administer and support the WLANs clients that are required to
connect to the network. There can be a wide variety of operating systems, WLAN clients, and user ability
to support, and a very limited amount of support resources. In cases like this, a typical solution is to
create an open WLAN that does not perform 802.1X/EAP authentication of encryption. This is normally
simple enough for all users and all platforms.
To provide some level of access control and audit trail, these WLANs perform a Web-Authentication
where all network access—apart from DHCP and DNS—is blocked until the user enters a correct
username and password into an authentication web page. This authentication web page will be forced to
the WLAN client screen when the client attempts to open any web page. Additional security policy may
be applied through filters on the WLC, upstream switch and/or firewall. See Figure 5-25.
Figure 5-25
Student Open WLAN General
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Figure 5-26 shows the QoS settings for the Student WLAN WMM is disabled, and the QoS profile of
Bronze. WMM is disabled to prevent WLAN clients on the Student assigning a WMM classification,
and the QoS profile of Bronze assigns network priority of less than best effort.
Note
802.11n standard requires WMM be enabled and, therefore, WMM must be enabled for all WLANs in a
802.11n deployments. In this case, the WMM policy would be set to allowed.
Figure 5-26
Student WLAN QoS
Figure 5-27 shows the security configuration for the student WLAN. Web policy presents a number of
web-based controls for network access, the option chosen in the case is authentication. Authentication
requires the client to enter username and password through a web page. The web page used can be an
internal server provided by the WLC, or to a third-party service.
Figure 5-27
Student WLAN Security
Figure 5-28 shows an example of the internal web page option for web authentication, this allows the
creation of a simple web page as shown in Figure 5-29.
The usernames and passwords for authentication can use the Local Net Users database on the WLC or a
RADIUS AAA server. The authentication mechanism between the WLC and the RADIUS is PAP.
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Note
Figure 5-28
Web Authentication Configuration
Figure 5-29
Web Authentication Example Screen
This web authentication mechanism can also be used with the WLC is used to provide wired guest
access.
AP Deployments Considerations
As with any other WLAN deployment, the key design decision are as follows: which areas require
coverage and what level of performance is required in those areas with WLAN coverage. The Schools
environment introduces an additional challenge to the design considerations due to the structured nature
of network use. That is, classes start at particular times and a teacher will often ask the entire class to
start an activity at the same time. This is a contrast to a typical enterprise deployment where network
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users are much more independent. The structured nature of a school network usage can greatly increase
the peaks in load upon the WLAN network. The general guidance for enterprise AP deployments has
been 15 to 20 active clients per AP, but the peaks in demand at schools has seen this translate into two
APs per class room, where there may be 20 to 30 students in that class room. The number of APs required
per class room depends on many factors, including the number of clients, the type of applications, and
the expected performance.
AP 1250
The Cisco 1250 Series is a rugged indoor access point designed for challenging RF environments that
require the antenna versatility associated with connectorized antennas, a rugged metal enclosure, and a
broad operating temperature range. The combined data rates of up to 600 Mbps to provide users with
mobile access to high-bandwidth data, voice, and video applications. 802.11n provides reliable and
predictable WLAN coverage to improve the end-user experience for both existing 802.11a/b/g clients
and new 802.11n clients.
AP 1140
The Cisco 1140 Series Access Point is a business-ready, 802.11n access point designed for simple
deployment and energy efficiency. The high-performance platform, which offers at least six times the
throughput of existing 802.11a/g networks, prepares the business for the next wave of mobile devices
and applications. Designed for sustainability, the Cisco 1140 Series delivers high performance from
standard 802.3af PoE while decreasing waste with multi-unit eco-packs and Energy Star certified power
supplies. As part of the CUWN, the Cisco 1140 Series provides the industry's lowest total cost of
ownership and investment protection by integrating seamlessly with the existing network.
Coverage and Site Surveys
The WLAN coverage requirements can be expected to vary from school to school depending upon their
goals and their budget. If the school is simply to try to provide wireless network connectivity in selected
classrooms, then simple tactical placement of APs in the selected rooms is likely to be sufficient. If the
school is planning to leverage the productivity associated with mobile application and mobile access,
then a more strategic approach is required.
If the school is planning to implement mobility solution, they need to examine the expected workflow
and movement of the users of these applications to determine the range of coverage required and perform
a site survey based on these coverage requirements. If the customer is considering WLAN location-based
services as a possibility for future deployments, this should also be taken into account during the site
survey process as the density and placement of APs can be substantially different when providing a
suitable WLAN platform for location-based services.
Single Band vs Dual Band APs
There are both single-band and dual-band APs available for schools solution. The single-band APs
support the 2.4GHz band and the dual-band APs support both the 2.4GHz and 5GHz band. It is a general
recommendation that a dual-band solution be deployed.
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Number of APs Per Room, Coverage in the School
Single band APs vs Dual Band APs
If your goal is to simply provide WLAN coverage without trying to optimize capacity and performance
then a single band AP is an appropriate choice, but in most cases a dual band Access Point is a better
long term choice.
The longevity of a WLAN deployment is fundamentally determined by it is capacity. A quick look at the
dual-band deployment shows that it has twice the capacity of a single-band solution, but a deeper look
will reveal that the advantage of a dual-band solution is much greater than an additional radio.
The additional 5GHz radio, of a dual band AP, is able to support a much higher capacity WLAN network
as it has access to approximately 7 times the number of non-overlapping channels as the 2.4GHz. In
almost all 2.4GHz deployments, APs reusing the three non-overlapping channels interfere with each
other and prevent the WLAN deployment from delivering a full WLAN capacity increase when the
number of APs is increased. A 5GHz AP is 7 times more likely to be able to delivery additional capacity
for the addition of an AP.
Another consideration in the single-band versus dual-band AP discussion is 802.11n performance.
802.11n uses two primary mechanism to provide data rate improvements over the existing 802.11g and
802.11a standards. The first mechanism changes in the modulation, and error correction that can provide
a data rate of up to 150Mbps, and the second mechanism is channel binding that combines
non-overlapping channels to deliver data rates that are multiples of what a single channel could achieve.
Channel binding is only available for the 5GHz band, as there is not sufficient channel capacity to
support it in an enterprise 2.4GHz deployment.
Deploying a dual-band WLAN system is not a matter of simply replacing the APs in place, the 5GHz
band has different power contraints, and has different propagation properties that need to be considered
when deciding on AP density and placement. If fiscally possible, a dual-band AP solution should be
planned and deployed initially. This will save an expensive rework layer.
For further discussion on 2.4GHz vs 5GHz capacity, refer to the Voice over WLAN Design Guide at the
following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/vowlan/41dg/vowlan41dg-book.html
Client Considerations
One additional consideration in the single-band versus dual-band AP decision is the client devices that
the WLAN network is going to support. Many earlier laptops and mobile devices only supported the
2.4GHz band, and this is still true for many consumer WLAN clients. To take advantage of a dual-band
solution a concerted effort needs to be made to ensure that as many clients as possible are also dual-band.
For cases where the school is purchasing WLAN clients, they should favor dual-band devices, in
recommending WLAN client devices they should point out that the dual-band client devices will have
access to a higher performance network. Of course, the first step is having the dual band network in
place, for client devices to take advantage of their investment in a higher performance client.
WLC Discovery
CUWN provides auto-discovery functionality for its APs, where an AP upon connection to an
appropriately connected network can automatically find and connect to a WLC. The WLC will ensure
that the AP is running the appropriate software version, apply the appropriate configuration to that AP,
and adjust the radio settings to optimize the AP for its current environment.
Multiple auto-discovery options are available in the CUW:
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•
Over the air: The APs learns the IP address of WLCs from APs in the area which are currently
attached to those WLCs
•
DHCP: The APs learns the IP address(es) of the WLCs as part of its DHCP address assignment
•
DNS: The APs learn the IP address(es) of the WLCs by querying and well known DNS name
CISCO-LWAPP-CONTROLLER.<localdomain.com>
•
Staging: Have the AP join a WLC prior to them being deployed, and the APs will attempt to rejoin
this WLC when reconnected to the network
•
Static Configuration: The APs can be manually configured with the WLC IP address prior to being
connected to the networks
Given that the schools architecture utilizes a local DNS server for school to ensure survivability the use
of the DNS discovery provides the simplest WLC discovery mechanism.
For details about how to configure DHCP discovery, refer to the DHCP OPTION 43 for Lightweight
Cisco Aironet Access Points Configuration Example at the following URL:
http://www.cisco.com/en/US/tech/tk722/tk809/technologies_configuration_example09186a00808714f
e.shtml
WLC Failover Options
CUWN provides multiple failover options allowing APs to make a choice between WLCs based upon
configured priorities. When an AP goes through its discovery process it learns about all of the WLCs in
the mobility group, and can prioritize based upon its high availability (HA) configuration or choose an
WLC based upon loads.
In network architectures, such as the schools SRA, where there is a high-speed WAN/MAN that makes
AP failover to a remote WLC—such as the district Office WLC—feasible, APs can be configured to
failover to a WLC outside their mobility group. In this scenario, the remote WLC would not be in the
Mobility Group that is learned during the AP discovery process, and the IP address of the remote WLC
need to be provided in the HA configuration.
This feature allows the distinct office to become a backup WLC for school sites in an event of an WLC
outage at the school. For this to be effective, a common WLAN SSID naming policy for key WLANs
needs to be implemented within the school district to ensure that WLAN client do not have to be
reconfigured in the event of an AP failover to the district office WLC. This type of HA configuration is
call N+1 where a single district office WLC is able to provide HA at a much lower cost than a traditional
1+1 design which would require additional WLCs at each school. See Figure 5-30.
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Appendix A—Devices and Software Used
Figure 5-30
AP High Availability Configuration Example
Appendix A—Devices and Software Used
Table 5-1 lists the devices and software used for the CUWN in this design guide.
Table 5-1
WLAN Devices and Software
Name
Version
WCS
6.0.132
WLC 4402
6.0.182.0
WLC 4404
6.0.182.0
AP1252
AIR-LAP1252AG-A-K9
AP1142
AIR-LAP1142N-A-K9
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6
Context-Aware Services Design
This chapter focuses on the application of general design best practices for the Cisco Context-Aware
Services (CAS) and the Cisco Mobility Services Engine (MSE) when integrating into the Service Ready
Architecture for Schools (SRA). It is intended as a guide to producing scalable and functional designs
that incorporate CAS, where such inclusion can be seen to provide real-world benefits.
Note that while this chapter attempts to be as comprehensive as is warranted by the subject matter being
discussed, it is not intended to be a comprehensive technical guide on Cisco Context-Aware Services,
RFID technology, or the Cisco Mobility Services Engine in general. For comprehensive configuration
and deployment information, the reader should refer to the in-depth configuration and deployment
guides mentioned throughout this chapter.
Introduction
What Are Context-Aware Services?
Context-Aware Services provides the ability to dynamically capture and use contextual information
about assets to optimize existing communications flows and organizational processes or facilitate the
establishment of new ones. Contextual information can be collected for assets involved in almost any
activity or process and this includes not just network endpoint devices (such as laptops and VoIP Phones)
and products (such as microscopes and video projectors), but in some cases also the users that are
associated with such devices.
In environments where the Cisco Unified Wireless Network has been deployed, Context-Aware Services
makes use of embedded 802.11 network interface adapters (radios) in wireless client devices to
accumulate contextual information about those assets or the user associated with the asset. For example,
the location of a wireless laptop can be calculated via several different approaches or the user name
associated with the laptop's user may be collected.
For assets that do not possess embedded wireless interfaces, external active Radio Frequency
Identification (RFID) tags and sensors can be used to provide location input and monitor ambient
environmental characteristics. Sensor capabilities can be directly embedded into active RFID tags in
order to link the data captured (for instance, whether the asset is currently in motion) with the location
of the asset. The algorithms used to determine location vary depending on the Radio Frequency (RF)
environment and the accuracy required for a specific application.
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In some cases, it may be necessary to track an asset with a high degree of accuracy throughout a school,
such as when it is necessary to determine where a missing valuable asset is currently located). On the
other hand, some applications using context-aware services may only require general indication of
whether an asset is in or out of a permissible zone (such as the confines of a chemistry lab area for
example).
Context-Aware Services can also provide location and other contextual information for wired devices
attached to certain Cisco Catalyst LAN switches. With the correct level of software, switches such as the
2960G, 3560E, 3750E, 3750G, 4500, and 4900 series can become context-aware. Catalyst switches that
are context-aware can provide civic location details for wired devices to the Cisco Mobility Services
Engine based on pre-configured information specified for each switch port. This information can then
be presented to users in a tabular format combined with other contextual information such as user name,
device serial number and emergency location identifier numbers (ELINs).
Note
A civic location specifies the civic address and postal information for a physical location using fields
such as the number, street or road name, community, and county assigned to residential, commercial,
institutional, and industrial buildings (e.g., 31 Main Street, Alpharetta, Georgia 30004). An emergency
location identifier number (ELIN) is a number that can be used by the local public safety answering point
(PSAP) to look up the geographic location of the caller in a master database known as the automatic
location information (ALI) database. The ELIN also allows the PSAP to call back the emergency caller
directly in the event the phone call is disconnected.
For a more detailed overview of Context-Aware Services, refer to the following URL:
http://www.cisco.com/en/US/solutions/collateral/ns340/ns394/ns348/ns788/solution_overview_c22-47
5173.html.
Why Use Context-Aware Services?
The information that can be provided by Context-Aware Services across its application API can
generally be classified into five functional categories, as shown in Figure 6-1.
Is It Here?
Five Functional Categories of Context-Aware Services
Where Is It?
What Is Its
Condition?
Condition
Asset Tracking
Tracking
Zone/
Inventory
Management
What Is Its
Status?
Where in
My Network
Is It?
Status
Network
Location
Services
227588
Figure 6-1
Is It Here?—Zone or Inventory Management
Zone or inventory management applications that utilize Cisco Context-Aware Services can define
specific zones in which they monitor mobile assets that possess embedded wireless interfaces or have
been outfitted with Cisco Compatible Extensions compliant RFID tags. These devices can be tracked and
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monitored when they enter and exit both permissible and non-permissible areas. Notifications can be
generated when monitored assets stray away into areas where they should not enter. Examples of how
zone or inventory management may be used in the school environment include:
•
Issuing notifications to administrators or school resource officers when school assets are moved out
of authorized areas
•
Alerting appropriate parties when persons equipped with RFID-enabled ID badges enter
unauthorized areas
•
Providing indication to teachers and assistants upon the arrival of an authorized parent or guardian
that has arrived to pick-up their children at the end of the day
Further details about zone or inventory management can be found at the following URL:
http://www.cisco.com/en/US/solutions/collateral/ns340/ns394/ns348/ns788/solution_overview_c22-47
5178.html.
Where Is It?—Asset Tracking
Asset tracking applications that incorporate Context-Aware Services can help locate assets within the
school, whether they are connected to wired or wireless infrastructure. In this way, Cisco Context-Aware
Services can provide great value to school administrators, teachers, security personnel, or anyone who
must quickly and effectively locate and recover missing assets. Examples of how asset tracking may be
used in the School environment include:
•
Locating wired and wireless portable assets (such as a portable video projector or flat panel display)
for class use or faculty presentations
•
Locating personnel possessing wireless VoWLAN phones or RFID-enabled badges in both
emergency and non-emergency situations
•
Identifying the past pattern of movement associated with an asset by enabling the review of archived
location history information in both a tabular and a graphical format. Such audit trails can be
especially useful when incorporated into security applications that can combine this information
with other information sources, such as video surveillance.
Further detail regarding asset tracking can be found at the following URL:
http://www.cisco.com/en/US/solutions/collateral/ns340/ns394/ns348/ns788/solution_overview_c22-47
5177.html.
What Is Its Condition?—Condition Tracking
Condition tracking applications utilizing Context-Aware Services can monitor select characteristics of
an asset's internal or external environment, such as variations in temperature, humidity, pressure,
quantity, fluid volume, etc. Any change in these characteristics beyond set thresholds can trigger alerts,
notifications, or other application-dependent actions. Examples of how condition tracking may be used
in the School environment include:
•
Temperature and humidity telemetry passed by RFID tag sensors can be utilized in school food
service applications to monitor the temperature of food refrigeration units, guarding against costly
spoilage and premature replacement.
•
Fluid level sensors placed in combination with RFID tags can be used to monitor critical fluid levels
in school maintenance applications, such as fuel oil levels for school generators and remote fuel
storage for building heating.
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•
Indication of excessive or insufficient pressure in systems such as school heating and cooling, school
labs (vacuum, air, and various gases), and so on can be passed as telemetry data using properly
equipped RFID tag sensors.
What Is Its Status?—Status Monitoring
Applications that monitor changes in user and asset status can use Context-Aware Services to detect
status transitions, such as a change from a normal state to one indicating that an extraordinary event has
occurred. Examples of how this may apply to the school environment include:
•
RFID tags with user push buttons could be used to covertly pass indication of situations where
assistance is needed, along with the location of the tag at the time of activation.
•
Attempted asset tampering, such as the removal of RFID asset tags themselves or jostling of any
type, can trigger status monitoring applications to generate alerts.
•
The introduction of new assets into a school location, or any changes in the motion status of existing
assets above a certain threshold, can serve as preliminary indication to building energy management
systems regarding potential building environmental modifications, such as lighting, zone heating, or
zone cooling.
Where Is It in My Network?—Network Location Services
Network location applications interfacing with the Context-Aware Services can help optimize the
distribution of both wired and wireless network resources, reduce troubleshooting time, help eliminate
waste due to use of network resources by unauthorized “rogue” devices, and help lower the overall total
cost of network operation. Examples of how this may apply to the school environment include:
•
Location and removal of unauthorized 802.11 wireless devices operating within a school building,
which helps reduce the school system's exposure to the introduction of malicious external software
as well as its liability to illegal file sharing activities.
•
Ongoing tuning of the wireless network by identifying areas where the routine congregation of
wireless users is heavier than expected. This may prompt adjustments in wireless network
parameters, the number of access points deployed, or the placement of access points.
Further detail regarding network location services can be found at the following URL:
http://www.cisco.com/en/US/solutions/collateral/ns340/ns394/ns348/ns788/solution_overview_c02-47
4514.html.
When combined with other applications constructed to take advantage of the Cisco Context-Aware
Services API, Context-Aware Services can serve as an enabler for entirely new application functionality.
For example, from their wired or wireless device, a teacher can consult a context-aware enabled
application that makes use of such information to determine the location of other faculty team members
(such as a nurse or resource school safety resource officer) and initiate contact with the nearest available
team member qualified to assist them. Context-aware services enhance the experience of users while at
the same time improving their overall efficiency and productivity.
Cisco Context-Aware Components
The components of the Cisco Context-Aware Services are shown in Figure 6-2.
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Cisco Context-Aware Services Components
Application and
Management
Figure 6-2
W
Mobility Services Engine (MSE)
with Context-Aware Software
N
S
Cisco Wireless
Control System (WCS)
E
Open API
Other Context-Aware
Applications
Si
Network
WLAN Controller
WiFi TDoA
Receiver
CAPWAP
Access
Points
CAPWAP
LWAPP
Catalyst
Ethernet
Switch
TDoA
RSSI
Triggers
Devices
Wired Clients
Cisco Compatible Extensions RFID Tags
WiFi Clients
227589
Chokepoint
RSSI
Wired and Wireless Client Devices
•
Wired or wireless (Wi-Fi) devices—Mobile wireless devices (asset tags, WiFi equipped computers,
mobile stations, etc.) that interact with the network and whose location and other contextual
parameters can be monitored by Context-Aware Services. Wired devices are generally equipped
with an Ethernet interface which is attached to a Cisco Ethernet switch (such as the 2960G, 3560E,
3750E, 3750G, 4500, and 4900 series) that supports context-aware services. In addition, some
devices may possess both wired and wireless interfaces. Without context-aware services deployed,
if a wired IP speakerphone is originally deployed in a school library, and a librarian moves this
phone to classroom 206 across the hall, any location information with regard to this conference
phone's whereabouts would need to be manually updated across all concerned systems. With
Context-Aware Services and a context-aware Ethernet switch, the location of the phone can be
dynamically updated to reflect its new location within seconds after it has been plugged into the
wired network jack in classroom 206. Via the Mobility Services Engine's API, this information can
be provided to various context-aware applications, including the Cisco Wireless Control System
(WCS).
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Introduction
•
Cisco Compatible Extensions RFID Tags—These RFID tags can be physically attached to assets
(regardless of whether the asset itself contains a wired or wireless network interface adapter) and
can pass contextual information on behalf of the asset to Cisco Context-Aware Services. Compliance
with the Cisco Compatible Extensions program helps ensure that RFID tags comply with predefined
information formats such that the contextual information they capture can be made readily available
to other Context-Aware Services components, including safety and security applications from Cisco
partners. Sensor capabilities can be externally mounted or directly embedded into tags in order to
link the data captured (for instance, motion, or temperature data) with the location of the mobile
asset. Externally mounted sensors can also be placed in fixed locations, like a refrigerator or a
storage room.
For more information about the Cisco Compatible Extensions for RFID Tags program, refer to the
following URL: http://www.cisco.com/web/partners/pr46/pr147/ccx_wifi_tags.html.
•
Chokepoint triggers—Chokepoint triggers (sometimes referred to as Exciters) are an optional
component that can greatly enhance asset tag functionality, providing for finer tag location
granularity and improved accuracy by localizing tagged assets within multi-floor structures, in
presence detection scenarios, or when passing through chokepoint areas, such as entrances and exits.
RFID asset tags that enter the proximity of a chokepoint trigger can change their normal behavior
based on a set of pre-programmed instructions. RFID tags that have been stimulated by chokepoint
triggers in this fashion send notifications and contextual information via the wireless infrastructure
to the Cisco Mobility Services Engine.
Cisco Unified Network
This multipurpose network contains the wired and wireless infrastructure required to address converged
data, voice, and video requirements, as well as providing the foundation for use of context-aware
services.
•
Note
•
Context-Aware Ethernet switches—These are Ethernet switches (such as the 2960G, 3560E, 3750E,
3750G, and 4500 series) that support the specification of civic and emergency location identification
number (ELIN) location information and the transmission of this information to Cisco
Context-Aware Services. This functionality allows for contextual information associated with wired
devices to be tracked using Context-Aware software on the Mobility Services Engine. Switches
transmit relevant contextual information to the MSE for all of the devices attached to them. This
information may include the physical mailing or street address location associated with the attached
device (the civic address) as well as other information such as the IP address, MAC address, port,
VLAN, and user name. Typically, this information is obtained using switch features such as IEEE
802.1x, Dynamic Host Configuration Protocol (DHCP) snooping, Dynamic Address Resolution
Protocol (ARP) Inspection (DAI), and IP Source Guard. Additionally, if the end device runs the
Cisco Discovery Protocol or Link Layer Discovery Protocol for Media Endpoint Devices
(LLDP-MED), additional information, such as the version number and serial number, can also be
sent to the MSE.
At this time, serial numbers of attached devices are reported to the MSE Context-Aware Service
only if the device supports LLDP-MED.
WLAN controllers—WLAN controllers (and the embedded software residing within them) provide
for the aggregation and transfer of device tracking and statistics information for RFID tags, mobile
wireless clients, and any rogue devices detected.
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– Access points—In addition to their fundamental role in providing access for wireless clients,
Cisco Aironet access points provide measurements of received signal strength from both
wireless client devices and RFID tags and subsequently forward this information to the Mobility
Services Engine via their registered WLAN controller.
– Received Signal Strength Indication (RSSI)—This is a mechanism used to determine device
location by carefully considering the measured strength of a radio signal at several points in an
indoor environment. Used by the Cisco Mobility Services Engine for WLAN clients, RFID tags,
and rogue devices, this algorithm is based on the signal sent from the mobile asset to different
access points deployed within the school. RSSI is usually preferred for indoor or low ceiling
environments, both of which can result in high degrees of signal reflection.
– Wi-Fi Time Difference of Arrival (TDoA) Receiver—Wi-Fi TDoA receivers are optional
components used in very large, open environments to locate assets equipped with RFID tags
with greater accuracy and precision than is possible using other techniques.
Note
Although useful in extending Context-Aware Services for RFID tagged assets in outdoor venues,
the use of TDoA receivers were not included in the Schools SRA design.
For a much more detailed explanation of both RSSI and other wireless location algorithms, refer to the
Wi-Fi Location-Based Services Design Guide 4.1 at the following URL:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/wifich2.html#wp1049520.
Management and Applications
•
Cisco Mobility Services Engine (MSE) with Context Aware Services Software—The Cisco Mobility
Services platform can host multiple independent services possessing high-level capabilities that can
enhance both wireless and wired network infrastructures. One of these is Cisco Context-Aware
Services which can capture, store, and analyze contextual information from multiple wired and
wireless networks simultaneously. When Context-Aware Services is deployed in accordance with
generally accepted best practices, both wired and wireless network infrastructure devices
(controllers and switches) may send raw location measurement data, device attachment, and other
contextual information to the MSE regarding the presence of any wired clients, wireless clients,
RFID tags, or rogue devices. Both wired and wireless network infrastructures communicate with the
MSE using the Cisco Network Management Services Protocol (NMSP), which is a Cisco-defined
protocol used for secure communication between the MSE and other context-aware network
infrastructure components. The MSE sits out of the data path of the wireless LAN and receives data
from WLAN controllers and context-aware switches via the use of NMSP.
The location of WLAN clients and RFID tags on the Cisco Mobility Service Engine is calculated by
one of two software service modules:
– Cisco Context-Aware Engine for Clients, which handles all context-aware operations involving
RSSI location of Wi-Fi clients, rogue clients, and rogue access points. This engine also handles
context-aware operations for wired clients.
– Cisco Context-Aware Engine for Tags, which handles all context-aware operations involving
TDoA and RSSI location of Cisco Compatible Extensions compliant RFID tags.
Context-Aware Services software, when operating alone on the Cisco MSE, is capable of servicing
up to a maximum of 18,000 simultaneously tracked devices per single MSE-3350 appliance and
2,000 simultaneously tracked devices per single MSE-3310 appliance.
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Refer to the following data sheet for more information regarding the Cisco 3300 Series Mobility
Services Engines
http://www.cisco.com/en/US/prod/collateral/wireless/ps9733/ps9742/data_sheet_c78-475378.html
•
Wireless Control System (WCS)—The Cisco Wireless Control System is a management platform
that also contains a context-aware client application that interacts with the Mobility Services
Engine. The primary role of the context-aware client application is to provide access to the
contextual information contained on the MSE using the MSE's application programming interface
(API). The application can then either present this information to the user directly (such as is seen
in a graphical location map or a table of location values) or enable other processes to accomplish
relevant tasks using this information that would otherwise be difficult to achieve. The Cisco WCS
can also serve in a special secondary role as a control client that possesses the ability to configure
MSE operational parameters.
For more detailed information on the Cisco Wireless Control System management server and its
capabilities, including its ability to serve as a context-aware application client, refer to the
documentation at the following URL:
http://www.cisco.com/en/US/prod/collateral/wireless/ps5755/ps6301/ps6305/product_data_sheet0
900aecd802570d0.html.
•
Other Context-Aware Applications—Other context-aware client applications from third party Cisco
Technology Development Partners may also access the MSE via its open API, which is based on
Simple Object Access Protocol (SOAP) and XML protocol. Access to this API is available to any
Cisco technology partner. Context-aware applications developed by Cisco Partners often deliver
specifically targeted application functionality that is often not available from other sources.
For more information on the Cisco Context-Aware Services API, refer to the following URL:
http://developer.cisco.com/web/contextaware/home.
Context-Aware Component Interaction
Figure 6-3 provides a more detailed illustration of the protocol interaction between the various
Context-Aware Service components.
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Figure 6-3
Protocol Interaction Between Context-Aware Components
WCS
Client
Browser
Cisco Partner
Context-Aware
Applicatons
HT
TP
SOAP/XML
S
WCS Server
SN
MP
NMSP
CA
AP
PW
PW
AP
CA
Access
Points
CAPWAP
WiFi Handsets, clients, rogues,
WFi Tags and chokepoint triggers
N
S
E
N
Mobility Services
Engine (MSE)
NSMP
W
Wireless LAN
Controller
CAPWAP
L
ns
atio
ic
otif
/XM
Catalyst
Switch
Wired Ethernet Clients
227590
MP
SN
For wireless clients, tags, and rogues, Cisco Aironet access points use the Control and Provisioning of
Wireless Access Points (CAPWAP) protocol to forward the RSSI of detected clients, tags, and rogues to
the WLAN controller to which they are currently registered. The wireless LAN controller aggregates this
information on a per device basis from all registered access points detecting the wireless device’s signal.
This information is then forwarded to the MSE using the NMSP protocol via an authenticated and
encrypted session. The appropriate Context Aware software engine on the MSE then uses the RSSI data
received from one or more WLAN controllers to determine the location of the wireless device
Note
A rogue access point is any access point that is determined not to be a member of the same mobility
group as the WLAN controller to which the detecting access points belong. A rogue client is any client
that is currently associated to a rogue access point.
For wireless clients, rogue access points, and rogue clients, the Context-Aware Engine for Clients is used
to process the received RSSI information. For operations involving RFID tags, however, the
Context-Aware Engine for Tags is used instead. Using Context-Aware Services and the Mobility
Services Engine, the Cisco Unified Network can readily detect 802.11 Wi-Fi active RFID tags that are
compliant with the Cisco Compatible Extensions for Wi-Fi Tags specification (such as those from
AeroScout, WhereNet, G2 Microsystems, and others). Through the MSE and WCS, the location of these
RFID tags can then be displayed on WCS floor maps using a yellow tag icon.
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Note
The Context-Aware Engine for Tags in Cisco Context-Aware Services Release 6.0 only tracks RFID tags
that are compliant with the Cisco Compatible Extensions for Wi-Fi Tags specification.
Cisco Compatible Extensions compliant active RFID tags are detected on a Wi-Fi network based on
periodic frames1 that are sent by the tag using a Layer-2 multicast. The delay between these periodic
frames can be programmed based on the specific application use case. In most cases, tags are configured
to transmit periodic frames every three to five minutes in order to strike an equitable balance between
location accuracy and good tag battery life.
RFID tags can also pass tag telemetry information upstream to the MSE as part of the tag message
payload. This contextual information (battery status, motion, temperature, pressure, humidity, etc.) is
received by access points and collected by WLAN controllers in a similar fashion as that described
earlier in this section. WLAN controllers will aggregate telemetry traffic from multiple tags and
eliminate any duplicate tag telemetry values that might be received. After the telemetry has been distilled
and cleansed of any duplicate information, the WLAN controller passes it to the MSE. The MSE updates
its internal databases with this information and in turn makes this information available to application
programs.
Properly equipped RFID tags can also indicate the occurrence of a priority event, such as one that might
result from the triggering of a tag tamper sensor or the depression of a tag call button. RFID tags indicate
that these types of events have occurred via additional information embedded in the tag messages that
are sent to the WLAN controller. This information is in turn passed northbound from the WLAN
controller to the MSE and the MSE can make this information available to application programs.
Several manufacturer's RFID tags include a secondary on-board magnetic signaling receiver, typically
set up to respond to the magnetic field component of a 125 kHz RF carrier. This secondary receiver
provides for additional tag functionality when tags enter into areas that are within close proximity to a
magnetic signaling transmitter or chokepoint trigger. Chokepoint triggers are proximity communication
devices that trigger asset tags to alter their configuration or behavior when the tag enters the chokepoint
trigger's area of operation or stimulation zone. This alteration could be as simple as causing the asset tag
to transmit its unique MAC address identifier. It could be significantly more complex, including causing
the tag to change its internal configuration and status. One of the prime functions of a chokepoint trigger
is to stimulate the asset tag such that it provides indication to the system that tag has entered (or exited)
the confines of a constricted physical area known as a chokepoint. Typical chokepoints include
entrances, exits or other types of physical constrictions that provide passage between connected regions
of a facility (such as a corridor or hallway).
Note
While chokepoint triggers are electronic devices that are typically deployed within physical chokepoints,
it is not unusual to hear the term “chokepoint” used rather loosely to refer to both the physically
constricted area and the associated electronic device.
Chokepoint triggers (including a very popular model manufactured by AeroScout Ltd. known as an
Exciter) may be connected to the wired infrastructure and are configured using each vendor's
configuration software. Once they have been configured, they can either remain connected to the
infrastructure full-time for management purposes or can be disconnected and operate in a standalone
mode, requiring a source of electrical power but no actual connectivity to the network.
1. These periodic frames are also sometimes referred to as “beacons”. They should not be confused with the
802.11 beacons that are sent by access points.
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The chokepoint trigger address information contained in the tag packet provides the MSE with enough
information to temporarily override any RSSI or TDoA localization currently in place for the tag and set
the current location of the RFID tag to the location of the chokepoint trigger. The size of a chokepoint
trigger's stimulation zone, or range, can extend from a radius one foot or less to over twenty feet,
dependent upon the vendor and the capabilities of the particular model.
Catalyst switches supporting context-aware services also make use of NMSP to interact with the MSE
similar to the manner described earlier for WLAN controllers. A major difference between how WLAN
controllers and Catalyst switches interact with context-aware services lies with the method used to
determine the location of switch attached wired devices. As explained earlier, localization of wireless
devices is performed by the MSE using a signal or time based technique, whereas the location of wired
devices is based on information sent to the MSE that originates in the switch configuration. The
information recorded by the MSE for the wired device includes the device MAC address, switch MAC
address, slot or port, IP address, and user name (if available). This information is sent whenever a device
link changes state. Context-aware Cisco Catalyst switches provide the MSE with the latest relevant civic
location and emergency location identification number (ELIN) information for all attached IP endpoints.
These endpoints may include IP phones, PCs, access points and other devices.
In Release 6.0, all civic and ELIN location information is configured locally at the switch, and shortly
after location changes are made using the CLI, they are propagated to the MSE. NMSP is used between
the switches and the MSE to maintain synchronization, and alert the switch as to the connection or
disconnection of devices.
Additional information regarding civic address location is available from the IETF in the following
RFCs:
Note
•
DHCP Option for Civic Addresses Configuration Information
http://www.rfc-editor.org/rfc/rfc4776.txt
•
Revised Civic Location Format for Presence Information Data Format Location Object
http://www.rfc-editor.org/rfc/rfc5139.txt
Proper validation of certificates between context-aware service components requires the participants to
possess sane clocks (clocks whose configured time does not differ from one another by large amounts).
In order to facilitate this, it is highly recommended that the clocks in the MSE, WCS, WLAN
Controllers, and any context-aware Ethernet switches be synchronized to a common time base using the
Network Time Protocol (NTP). The lack of clock sanity amongst context-aware components in the
network can cause NMSP sessions to fail if the configured date and time fall outside of the certificate
validity period and cause certificate validation to fail.
Network Mobility Services Protocol (NMSP)
The Network Management Service Protocol (NMSP) was designed to define intercommunication
between Mobility Service Engines and network access controllers over a switched or routed IP network.
An access controller can provide network access for either wired or wireless endpoints. Within the scope
of the Schools SRA design, access controllers are represented by WLAN controllers and context-aware
Cisco Catalyst Ethernet switches.
NMSP is a two-way protocol that can be run over a connection-oriented or a connectionless transport.
WLAN controllers and context-aware switches can use NMSP to communicate with one or more MSEs.
NMSP is based upon a bidirectional system of requests and responses between the MSE and the access
controllers.
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MSP also provides for a keepalive feature that allows either partner in a NMSP session to determine if
the adjacent partner is still active and responsive. Should an MSE fail, a WLAN controller or a
context-aware Ethernet switch will try to contact another MSE with which to communicate. If the
WLAN controller or context-aware Ethernet switch fails, all context-aware services being provided to
that WLAN controller or context-aware Ethernet switch are disabled until that WLAN controller or
context-aware Ethernet switch once again becomes active and re-establishes its NMSP session.
Note
It is important to understand that the failure of an NMSP session has no direct impact on the ability of a
WLAN controller or context-aware capable Ethernet switch to pass normal client session traffic to
applications on the network. In other words, a failed NMSP session to a WLAN controller may affect
the ability of the MSE to provide updated contextual information on that controller and its resources.
But it does not affect the ability of the WLAN clients using that WLAN controller to logon to
applications residing on the network. This also applies to wired clients and context-aware Ethernet
switches.
NMSP uses Transport Layer Security (TLS) and TCP port 16113 on the WLAN controller or
context-aware Ethernet switch. The MSE will initiate the connection to the WLAN controller or
context-aware Ethernet switch, although once a secure session has been established between MSE and
its session partner, messages may be initiated in either direction. The TCP port (16113) that the
controller and mobility services engine communicate over must be open on any firewall that exists
between the controller and mobility services engine.
The MSE and the WLAN controller or context-aware Ethernet switch use Echo Request and Echo
Response control messages to maintain an active channel of communication so that the data messages
can be sent. The Echo Request message is a keepalive mechanism that allows either NMSP session
partner to determine if the other partner remains active and responsive. Echo Requests are sent
periodically (upon expiration of a heartbeat timer) by the MSE or its session partner to determine the
state of the NMSP session. When the Echo Request is sent, a NeighborDeadInterval timer is started. The
NeighborDeadInterval timer specifies the minimum time a session partner must wait without having
received Echo Responses to its Echo Requests, before the other session partner can be considered
non-responsive and the NMSP session is placed in an idle state.
Context-Aware Services in the Schools Service Ready
Architecture
Figure 6-4 provides a high level illustration of the integration of Cisco Context-Aware Services into the
Schools Service Ready Architecture. The key points of this integration into a Metropolitan Area
Network deployment are:
•
The presence of a centralized management entity (the wireless control system (WCS))) at the
district office. In the case of Context-Aware Services, WCS also serves as a context-aware
application client. District and school context-aware users can log into WCS and query the
contextual characteristics (such as location) associated with wireless and wired client devices,
rogues and asset tags. In some cases, third-party context-aware application servers may also contain
context-aware applications that are located in the district office.
•
The presence of a local Mobility Services Engine at larger schools used to provide Context-Aware
Services to individual larger schools, where the anticipated number of total tracked devices is
significantly higher (e.g., greater than 500 and most likely 1000 or more). A locally deployed MSE
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may also be justified if context-aware services are being utilized for school applications and tasks
that are considered mission-critical to the function of the school or the safety and security of
students or faculty.
•
Figure 6-4
The option of a centralized Mobility Services Engine with Context Aware software at the district
site used to provide the Context-Aware Services to smaller schools where the anticipated number of
total tracked devices per school is relatively low (e.g., less than 500).
High-Level View of the Schools SRA With Hybrid Context-Aware Services Model
Optional Backup
WLAN Controller(s)
Access
Control
System
Wireless
Control System
WLAN
Controller
MSE
District
Office
Services Block
Cisco 2960G
Mobility Services
Engine
Cisco 3750G
IP
IP
Metropolitan
Area
Network
Access
Control
System
Access
Control
System
MSE
School Site
Cisco 4500
Distribution
WLAN
Controller
Cisco 2960G
Mobility Services
Engine
Cisco 3560G
Cisco 2960G
IP
Cisco 3750G
IP
IP
227595
IP
School Site
Cisco 3750 Stack
Distribution
WLAN
Controller
Except for very large or very small school districts, it is our understanding that the majority of School
districts addressed by the Schools SRA design will contain a mix of large schools (such as high schools)
and smaller schools (such as elementary and intermediate schools). We anticipate that many of the
smaller schools in these districts may be well served by the 3750 switch stack used at the distribution
layer, whereas larger school designs may be outfitted instead with the 4500 distribution switch. In
situations such as this, the context-aware deployment model shown in Figure 4 can be used to provide
context-aware services to both types of schools.
Historically, context-aware services and the Cisco Mobility Services Engine (as well as its predecessor,
the Cisco Wireless Location Appliance) were designed to be deployed within modern switched LAN
environments. In such deployments, FastEthernet speeds and capacity (or better) are typically assumed
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to be present throughout the local area network. Due to the lower speeds associated with traditional
wide-area networking technologies (such as frame relay, T-1, and so on), context-aware components
have not been recommended for deployment across traditional WANs. In fact, if context-aware services
are to be deployed in remote sites possessing only traditional WAN connectivity, Cisco Systems has
typically always recommended that the MSE be deployed locally along with WLAN controllers and any
other components establishing NMSP sessions to the MSE. In addition, designers may wish to break up
large WCS network designs into smaller designs to avoid time outs that can occur between WCS and the
MSE during synchronization of very large network designs when using low-speed links2.
While the cost of local MSE deployment can be very applicable to very large remote sites whose device
population can justify it, this is typically not true in the case of smaller sites with lower device
populations. Looking at the general case of school districts that might contain a mix of larger and smaller
schools, we can easily see that this local versus remote dilemma applies in the case of the Schools SRA
design as well.
A key difference (and advantage) of In the Schools SRA design, is that the use of a modern high-speed
metropolitan area network (MAN) to interconnect remote schools offers far more bandwidth to each
remote site than would be seen with a traditional WAN deployment. In this case, with modern LAN-like
speeds available across the metropolitan area network, the concept of deploying an MSE remotely from
the other context-aware components begins to resemble the look and feel of a local LAN deployment,
and thus becomes much more feasible. Note however, this assumes sufficient bandwidth and
infrastructure is in place to assure that FastEthernet-like speeds are available to each school and that
proper network protocol identification, classification and QoS are all applied properly to manage
congestion in the network.
In the context-aware services model shown in Figure 6-4, we take advantage of high-speed connectivity
across the MAN to the remote schools and allow for a centralized MSE to provide context-aware
services for smaller schools across the district. We assume here that on their own, a single small school
might only have a maximum of 250 to 500 simultaneously tracked devices. An exception to the case
made for using a centralized MSE for smaller schools might be for any schools where context-aware
services are used for applications that are mission-critical to the safety and security of the school, its
students, and the faculty and administration. An example of such an application might be a safety and
security application used to ascertain the location of all faculty or students during a school lock-down
security event using identification cards that are equipped with RFID technology. This type of
application obviously must be available at all times, including any potential network outages, hence the
use of a centralized MSE in this case is not an option. Any other supporting applications that are required
for such mission-critical deployments of context-aware services should also be deployed locally in this
case as well.
Note
Based on our analysis of MAN capacity, traffic flows, classification and QoS, we believe the centralized
deployment of an MSE across a modern high speed metropolitan network is a viable concept. Although
a great deal of intensive functional testing was performed during the preparation of this chapter, time
constraints did not allow us to complete validation of centralized MSE deployments across metropolitan
area networks.
Larger schools using a 4500 series Catalyst Ethernet switch for distribution are assumed to possess at
least 500 or, more likely, 1000 or more simultaneously tracked wired or wireless devices. While it may
be possible to service these larger schools using a centralized MSE, the larger number of clients and the
increased amount of traffic placed onto the MAN between controllers, switches, and the MSE in this case
can pose more of a challenge, especially when there are large device populations that move frequently
and generate location updates on a regular basis. Careful analysis of data traffic and the judicious
application of QoS in the network becomes especially important.
2. Or use a locally deployed WCS at each remote site that could optionally be managed by WCS-Navigator at a
central site.
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At the current time, the most reliable known solution in the case of larger schools with large tracked
device populations is to deploy an MSE locally at the school. This MSE can in turn be managed via a
remote WCS at the district office. Once again, in cases where context-aware services are regarded as
mission critical for the school, other context-aware components (such as third-party context aware
application servers or in some cases the WCS as well) should also be deployed locally in order to ensure
that the context-aware solution is functional even in the rare case of a prolonged MAN failure.
In school districts where there are many schools with either large tracked device populations or
mission-critical context-aware applications, it is important to keep in mind that at this time Cisco
officially supports the management of up to five (5) MSE platforms from a single WCS system. While
this is not a “hard” limitation on the number of MSE platforms that can be assigned to a single WCS
system, it is the limit to which testing has been performed. Therefore, in designs where there may be
greater than five large schools equipped with locally deployed MSE platforms, you may wish to consider
using additional WCS systems as necessary. In this case, the use of WCS-Navigator (not shown in
Figure 6-4) should be considered at the district office to provide a single interface portal to as many as
twenty (20) WCS management systems and their associated Mobility Services Engines. WCS-Navigator
is a management aggregation platform that delivers enhanced scalability, manageability, and visibility
of large-scale implementations of Cisco WCS and the Cisco Unified Network. WCS-Navigator provides
straightforward access to information from multiple Cisco WCS management platforms. A single
WCS-Navigator management aggregator can support up to twenty (20) WCS management systems and
30,000 access points.
Note
Due to time constraints, scalability testing of WCS-Navigator in the Schools SRA design beyond four
WCS systems was not able to be completed. Further information on WCS-Navigator can be found at
http://www.cisco.com/en/US/products/ps7305/index.html.
Component Capacities
Mobility Services Engine
Each Cisco Mobility Services Engine has a maximum device tracking capacity, defined as the maximum
number of active wired and wireless (clients, rogues, and RFID tags) that can be tracked by a single
Mobility Services Engine. This is a “hard” limit that is dictated by the licensing purchased for the
Context-Aware software as well as the presence of any other applications on the MSE. Once a Mobility
Services Engine has reached its maximum tracking capacity, any new devices that the MSE becomes
aware of beyond that limit are simply not tracked. It is important to note that while this section discusses
the maximum device tracking limits for the MSE, MSE licenses can be purchased supporting device
limits significantly lower than those shown here. Refer to the MSE Licensing and Ordering Guide
(http://www.cisco.com/en/US/prod/collateral/wireless/ps9733/ps9742/data_sheet_c07-473865.html)
for more information regarding the various combination of client and RFID tag tracking capacities
available for the MSE.
For Release 6.0, the maximum device tracking limits when using only the Context-Aware Services
software on the MSE are shown in the following table:
Mobility Service Engine Maximum Tracked Device Capacity
MSE-3350
18,000
MSE-3310
2,000
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If you intend to use the MSE-3350 to deliver other services in addition to Context-Aware, the maximum
capacity shown above in Table 2 will likely be reduced. See the MSE Licensing and Ordering Guide
(http://www.cisco.com/en/US/prod/collateral/wireless/ps9733/ps9742/data_sheet_c07-473865.html)
for information on Context-Aware maximum tracked device limits with other co-resident MSE services.
When working within these maximum capacities, it is important to note that further category-specific
limits can be instituted at the designer's discretion via the MSE configuration. This allows, for example,
a maximum capacity of 2,000 tracked devices on a MSE-3310 to be further limited as 1,000 wired and
wireless clients, 500 RFID tags, and 500 rogue access points and clients. Partitioning the maximum
tracking capacity of the context-aware software in this manner prevents any single device category from
consuming more than its authorized share of the maximum tracking capacity of the system.
In the high-level diagram shown in Figure 6-4, the MSE-3310 might be a good design choice for a
locally deployed MSE at our 4500-based school site. Its maximum tracked device capacity of 2000
devices should scale well to a larger school site with an estimated 1000-1250 total tracked devices. This
would leave ample MSE capacity in reserve for future growth in tracked devices at this location. Of
course, you could deploy with less capacity in reserve should you choose to, and elect to address future
tracked device growth at a later date via a hardware addition or upgrade. 4500-based schools that possess
or anticipate near-term tracked device needs beyond 2000 devices should consider the MSE-3350
instead.
Except for very small school districts, the MSE-3350 would typically be the best overall choice when
considering a centralized deployment using a high-speed metropolitan area network. In this way, it can
provide context-aware services for several smaller school sites, each of which might possess an
estimated 500 or fewer tracked devices. In very small school districts (e.g., a district containing up to
four small schools for example) a centralized MSE-3310 may prove to be even more cost-effective.
WLAN Controllers
WLAN controllers also possess limitations on the maximum number of devices for which the controller
will track and aggregate contextual information. In Release 6.0, these limits are shown in Table 6-1.
Table 6-1
Maximum Device Limitation
WLAN Controller Clients Tags
Rogue Access Points Rogue Clients
4404
5000
2500
625
500
4402
2500
1250
625
500
2106
500
256
125
100
Note that these are indeed “hard” limits. In other words, once these limits have been achieved on a
WLAN controller, contextual tracking information for any new clients, RFID tags, rogue access points,
or rogue clients beyond these limits will be dropped until such time that older entries are pruned from
the controller's internal database. The client and tag limits are quite high and should not prove to be
easily exceeded for a single school. Unless students are allowed to operate their own unauthorized rogue
WiFi equipment during school hours (which is typically not the case as per our understanding), the
limitation on the number of rogue devices tracked by a single controller should not be routinely exceeded
in a single school.
The Context-Aware System Performance chapter of the Mobility Services Engine Context Aware
Deployment Guide
(http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml#casysper
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f) also points out that a single MSE can support up to 500 total NMSP connections. Keep in mind this
includes not only the NMSP sessions to WLAN controllers, but NMSP sessions to any context-aware
Ethernet switches conducted from that MSE.
Note
Although a single MSE can technically support up to 500 NMSP sessions, scalability testing constraints
have only allowed for testing of 100 simulated NMSP connections to a single MSE at this time.
Wireless Control System (WCS)
With regard to the MSE, WCS interacts as a context-aware client and does not track devices itself when
used in conjunction with the MSE. Thus, there are no direct constraints on the maximum number of
tracked devices imposed by WCS itself.
In addition to established WCS sizing and capacity guidelines for the number of supported controllers
and access points (listed in the System Requirements section of the Wireless Control System
Configuration Guide, Release 6.0,
http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0wst.html#wp1061082),
there are a few indirect constraints relating to Context-Aware services that you should be aware of:
•
To maintain clarity and the speed of its graphical user interface, WCS only displays the first 250
wireless clients, RFID tags, rogue clients, or access points on a single floor map. To view graphical
location displays for any of these device categories beyond this limit, filtering (based on MAC
address, asset name, asset group, asset category, or controller) should be used to limit the number
of devices displayed at once (see the Floor Settings section of the Wireless Control System
Configuration Guide, Release 6.0,
http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0maps.html#wp121096
9).
•
Currently, a single WCS can manage Context-Aware Services on up to five (5) Mobility Service
Engines. While defining more than five MSEs to a single WCS is possible, Cisco Systems has not
validated this level of operation.
•
Currently, Context-Aware Services on the Mobility Services Engine can be managed by only one
Wireless Control System.
•
In Release 6.0, WCS supports the creation of up to 124 WCS virtual domains.
Context-Aware Engine for Tags (AeroScout)
The Context-Aware Engine for Tags used in version 6.0.85.0 of the MSE Context-Aware Services
software supports network designs containing up to 255 floor maps. A network design typically consists
of campus, buildings, and floor maps. Thus, in the Schools SRA, a network design might be used to
describe a school district. This limitation could be interpreted as saying that a school district should not
contain more than 255 floor maps. If more than 255 floor maps are required, it is necessary to break the
school district up into two or more network designs.
Obviously, the degree of restriction here will vary with the number of floors in each school in your
district, multiplied by the number of schools. For example, if all schools in a district contain only a single
floor, then up to 255 schools could be defined in a single network design before the conditions of this
restriction are encountered. If schools each contained three floors however, then only 85 schools could
be defined before being subject to this limitation.
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Integration with the Schools Service-Ready Architecture
MSE Connection to the Network
Figure 6-5 is an illustration of the rear panel of both the MSE-3350 and the MSE-3310. The Cisco
Mobility Services Engine is equipped with two 10/100/1000BASE-T Gigabit Ethernet ports (shown in
Figure 6-5 by the solid arrows) that can be used to directly connect the MSE to two different IP networks
(dual-homed). This makes it a simple affair, for example, to configure a MSE for service on network A
while affording it the capability to be managed out-of-band on network B if the need arises.
In the Schools SRA design, we attach the MSE to the network via a single connection to the NIC0
interface.
Figure 6-5
Note
Rear Panel Illustration of MSE-3350
NoteThe dual on-board Ethernet controllers on the MSE are not intended for redundant or simultaneous
connections to the same IP network. Any attempt to manually configure the MSE in order to try and
establish parallel, load balancing, or redundant Ethernet connections to the same IP network is not
recommended or supported at this time.
Clock Synchronization
The Mobility Services Engine, WCS, WLAN controllers, and any switches that support context-aware
services use Coordinated Universal Time (UTC)3 in their interaction. Because proper certificate
authentication relies on time base consistency between participating components, it is important to
ensure that these components are synchronized to a common time base throughout the Schools SRA
design. In addition, having components synchronized to a common time source makes troubleshooting
much easier, especially when having to look at events occurring within the logs of different network
components. And the output of coordinated information by a central source, such as WCS, makes much
more sense when the time stamps of all information displayed follow a logical flow and make sense to
the user.
Once time and date in each network component has been set initially, time synchronization should be
maintained using the Network Time Protocol (NTP). In the Schools SRA design, these components
should be synchronized to the local school or district ISR router.
3. For applications such those anticipated in the Schools SRA, Universal Coordinated Time may be considered
as equivalent to Greenwich Mean Time (GMT).
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NTP Configuration of the Mobility Services Engine
Configuration of the NTP server addresses used by the MSE is handled during installation and the
execution of the MSE automatic configuration script. An excerpt of that script is shown below. Detailed
information regarding the automatic configuration script can be found in the Automatic Installation
Script section
(http://www.cisco.com/en/US/docs/wireless/mse/3350/quick/guide/mse_qsgmain.html#wp1057105) of
the Mobility Services Engine Getting Started Guide,
http://www.cisco.com/en/US/docs/wireless/mse/3350/quick/guide/mse_qsgmain.html#wp1057105, and
in Appendix A
(http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml#appena)
of the Mobility Services Engine Context Aware Deployment Guide,
http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml#appena.
If you choose to enable NTP, the system time will be configured from NTP servers that you
select. Otherwise, you will be prompted to enter the current date and time.
NTP is currently disabled.
Configure NTP related parameters? (Y)es/(S)kip/(U)se default (S)kip: Y
Enter whether or not you would like to set up the Network Time Protocol (NTP) for this
machine.
If you choose to enable NTP, the system time will be configured from NTP servers that you
select. Otherwise, you will be prompted to enter the current date and time.
Enable NTP (yes/no) no : yes
Enter NTP server name or address: <IP address or DNS name of NTP server>
Enter another NTP server IP address (or none) none: none
NTP Configuration of WLAN Controllers
Configuration of the internal clock and the specification of which NTP servers to use for periodic time
synchronization can be performed on the WLAN controller using either the web GUI interface or the
command line interface.
If you did not configure the system date and time through the configuration wizard when the controller
was initially configured, or if you want to change your configuration, you can follow the instructions
located in the section entitled Managing the System Date and Time
(http://www.cisco.com/en/US/docs/wireless/controller/6.0/configuration/guide/c60intf.html) in the
WLAN Controller Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/controller/6.0/configuration/guide/c60intf.html#wp11443
40) in order to configure the controller to obtain the date and time from a Network Time Protocol (NTP)
server.
NTP Configuration of the Wireless Control System (WCS) Server
Configuration of the internal clock and the specification of which NTP servers to use for periodic time
synchronization must be performed on the WCS server using the time and date capabilities of the WCS
host operating system in use (either Windows or Linux).
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RHEL-Based WCS Server
For a Redhat Linux-based WCS server, login to the host OS as root and use the following procedure to
synchronize the internal software clock to the NTP server, synchronize the software clock to the server's
hardware clock, and then maintain synchronization by starting the ntpd client daemon:
1.
clock—Displays the current setting of the software clock.
2.
/etc/init.d stop—Stops the ntpd client if it is already running.
3.
ntpdate <ntp server name or address>—Synchronizes the system software clock with the NTP
server.
4.
setup—Brings up a setup utility that allows you to choose to set the time zone (shown in
Figure 6-6).
5.
hwclock-systohc—Writes the software clock settings to the hardware clock.
6.
/etc/init.d/ntpd start—Starts the ntpd daemon to keep the clock synchronized going forward. 4
Figure 6-6
Note
RHEL Setup Utility
There are various other approaches that can be used to set the time zone on a Linux system. The reader
is encouraged to consult the Redhat documentation for methods involving the use of the TZ variable or
symbolic links to the localtime file or a particular time zone file in the system’s time zone directory.
Windows 2003-Based WCS Server
For a WCS server based on the Microsoft Windows 2003 Server OS, use the following procedure to
synchronize and maintain the correct system time via the Windows Time service (see Figure 6-7):
1.
Check Settings>Control Panel >Administrative Tools>Services for the Windows Time service
and ensure that it has been started.
2.
Right click on the Task Bar clock and select Adjust Date/Time.
3.
Under the Date & Time tab, set the current date and clock time to the approximate time of your NTP
server.
4. If ntpd does not start as part of your system boot script, you might want to add it using the command chkconfig
--add ntpd.
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4.
Set the Time Zone and Daylight Savings time selections appropriately.
5.
Select the Internet Time tab, check the box to Automatically Synchronize With An Internet Time
Server, type in the DNS name or address of your NTP server, and then Apply.
Figure 6-7
Setting Time and NTP Server on Windows 2003
NTP Configuration of Context-Aware Catalyst Ethernet Switches
In order to prevent any issues with authentication and NMSP session initiation, Catalyst Ethernet
switches participating in context-aware services should be configured to utilize NTP in order to keep
their clocks in synchronization with other context-aware components. NTP is configured similarly
amongst the various switch models discussed in this chapter, and the most comprehensive information
on how to configure a Catalyst switch as an NTP client can usually be found in the configuration guide
for the particular switch model. For example, for the Catalyst 2960G NTP configuration is documented
in Configuring NTP section of the Catalyst 2960 Switch Software Configuration Guide
(http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_50_se/configurati
on/guide/swadmin.html#wp1053923).
It is good general best practice to ensure time synchronization of all network components when possible.
However, from the perspective of context-aware services in the Schools SRA, only those switches that
are actually participating in an NMSP session with the MSE require clock synchronization.
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Schools SRA Wireless Control System (WCS) Context-Aware Considerations
The Wireless Control System is used for several important configuration tasks relating to context-aware
services in the Schools SRA:
•
Creation of a School or School District Network Design, which may include campus, building, floor,
and outdoor level maps.
•
Definition of WCS User Groups, which are used to define what management actions school
context-aware users are authorized to perform with regard to network resources.
•
Definition of Virtual Domains, which can be used to restrict which network resources school and
other users have the ability to manage via WCS.
•
Configuration of Mobility Service Engine operating parameters. This represents the next level of
MSE setup beyond that performed by the MSE automatic configuration script discussed in section
NTP Configuration of the Mobility Services Engine.
•
Definition of Context-Aware Conditional Notifications, which defines how applications and parties
external to the School might receive notification of specific events pertaining to changes in
contextual characteristics associated with clients, tags or rogue devices.
In this section, we discuss only those areas where, in our testing of the Schools SRA design, we made
use of significant WCS features relevant to the integration of context-aware services in our design, or
where important configuration changes were made that significantly differ from the defaults. This is not
meant to serve as a comprehensive configuration guide to all aspects of the WCS and MSE. Readers
should refer to the WCS and MSE configuration documents already cited throughout this document
(including Context-Aware Services General Best Practice References) for additional information
regarding configuration parameters and procedures that, while not discussed in detail here, must still be
configured or performed properly.
Creation of a Network Design
Once access points have been installed and have registered with a controller, WCS can be configured to
manage the controllers and a network design can be set up. A network design is a representation within
WCS of the physical placement of access points and other context-aware components throughout a
facility or group of facilities. A hierarchy consisting of a single campus, the buildings that compose that
campus, the floors of each building, and any outdoor areas constitutes a single network design.
In the Schools SRA, the choice of whether to configure the school district or each individual school at
the campus layer depends to a large part on the on whether the schools in the district each contain a single
building, or multiple buildings. If each school is comprised of one building and one building only, then
the campus layer of the network design can be the entire school district. On the campus map, each school
would be represented by a single building with one or more floors per building. This might be seen
where:
•
Schools are of more recent vintage and may have been sized accordingly for larger student
populations. School temporary or portable outbuildings are not seen in this type of scenario.
•
Areas where student population is relatively low, and there is no need for any secondary outbuilding
structures at schools to meet student population demands.
In other cases, schools might be composed of multiple buildings, such as:
•
An older school which has been expanded via the use of one or more secondary outbuildings. This
might also be the case despite the age of the school if the surrounding communities have experienced
explosive population growth.
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•
Larger schools that were architecturally designed to be small campuses, with multiple buildings,
outdoor venues and the potential for large student populations. In some areas, this may be seen in
high school settings.
In these scenarios, it makes more sense to define the school as a campus in and of itself if
context-services will be deployed in two or more buildings or parts of the school campus.
A step-by-step set of configuration instructions regarding how to configure network designs consisting
of campus, building, and floor maps can be found in Chapter 5 of the Cisco Wireless Control System
Configuration Guide, Release 6.0,
http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0maps.html#wp1203275.
Figure 6-8, Figure 6-9, and Figure 6-10 give an example of what a campus, building, and floor level
network design might look like for a school district where all schools are assumed to be comprised of
single buildings. In Figure 6-8, we use satellite imagery of the school district area as the backup for the
campus map. Clicking on any of the icons takes us to the building map for the school. In this case, we
select high school number 1278, which then brings us to Figure 6-9.
Figure 6-8
Campus Level
The building map shown in Figure 6-9 indicates that this school is composed of a single floor. Clicking
directly on the building map takes us to the floor definition shown in Figure 6-10. This is where we
would actually see the location of wireless clients, active RFID tags and rogues displayed. Wired devices
that are attached to context-aware Ethernet switches are not displayed on floor maps in Release 6.0 of
Context-Aware Services.
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Note
Figure 6-9
Building Level for School #1278
Figure 6-10
Floor Level for School #1278
Network designs are created in WCS, but they are not actually used for device tracking until they are
transmitted to the MSE via a process known as network design synchronization. Only after network
design synchronization has successfully occurred between WCS and its associated MSE will the network
design actually be used by the Context-Aware Engine for Clients and the Context-Aware Engine for
Tags. Synchronization of network designs and other components with the MSE is discussed in detail in
the chapter entitled “Synchronizing Mobility Services Engines” in the Context-Aware Service
Configuration Guide 6.0,
http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch3_CAS.h
tml.
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WCS Users, User Groups, and Virtual Domains
When installed, WCS provides for a single root user, which will have access to all WCS functions. The
password for this root user should be protected and only known by those personnel at the district data
center with a true need to know (e.g. those personnel responsible for the installation, maintenance, and
detailed administration of WCS). Instead of using the root user password for routine access to WCS, you
should create other users and grant them administrative access with privileges assigned as necessary via
the use of WCS user groups. Chapter 7 of the Cisco Wireless Control System Configuration Guide,
Release 6.0 (http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0manag.html)
provides comprehensive instructions with regard to the proper procedure for configuring users and group
privileges on your WCS server. This chapter also contains a complete listing of the user groups available
in WCS as well as the privileges contained in each group.
Common sense should be applied in the assignment of user privileges in the Schools SRA. For example,
while only a very small set of key technical personnel should have access to the actual WCS root user
ID and password, you may wish to assign the ability to make WCS configuration changes to a somewhat
larger audience. This larger group can be assigned as WCS “admin” users or assigned to the “superuser”
group. Most school users that are only interested in viewing the information available to them on WCS
will not need more than the ability to simply monitor network activity in WCS. For these users, the
privileges accorded them by the WCS System Monitoring or Monitor Lite user groups may be all that is
required, depending upon the specific WCS monitoring functions you wish to grant those users.
In our validation of the Schools SRA, the custom user-defined group shown in Figure 6-11 was found
to be very useful in limiting users to only monitoring context-aware information, as well as some basic
WCS alerts and events. Note that the user is not allowed free rein to use any of the monitoring functions
provided by WCS. For example, we may wish to allow a librarian in a school to access the context-aware
functions listed under the WCS “Maps” function or search for a device by name. But this same school
librarian probably has no need to monitor school network security compliance reports, thus we have not
enabled access to those reports for this librarian's WCS account. Keep in mind that the requirements of
school users in your environment may be different, so it may make sense for you to develop a custom
WCS user group that closely fits your needs.
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Figure 6-11
Custom User Group to Allow Context-Aware Monitoring
While WCS user groups define the WCS functionality users have been granted, WCS virtual domains
allow the network administrator logically partition the WCS management domain and limit management
access. In this way, the group of resources that the WCS functionality assigned to a user group may be
exercised against is restricted. A WCS virtual domain consists of a set of assigned devices and maps,
and restricts a user's scope to only information that is relevant to those devices and maps. Through a
assigned virtual domain, users are only able to utilize WCS functionality against a pre-defined subset of
the devices managed by WCS.
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Users can be assigned one or more virtual domains, however only one assigned virtual domain may be
active for a user at WCS login. The user can change the current virtual domain in use by selecting a
different permitted virtual domain using the WCS Virtual Domain drop-down menu.
The WCS virtual domain can be used to limit the user's ability to even view certain resources inside WCS
that are not contained in their active assigned virtual domain. For example, the Physics department
chairman of a high school may have the ability to view the location and other context-aware
characteristics of wireless assets due to his WCS user account being assigned to an appropriate user
group permitting this level of WCS functionality. But the virtual domain that this department chairman
director is assigned may only allow such functionality to be exercised against these assets if they are
located within his assigned school. Thus, if the chairman of the physics department for school “A”
attempted to use WCS to discover the quantity and location of RFID-tagged equipment in school “B”,
his assigned virtual domain would not allow access to school B's resources.
Administrative personnel with district-wide responsibilities, on the other hand, would be assigned a
virtual domain that includes all resources in the district, including those in each school, and could
exercise the functionality assigned to them by their user group against any of these resources. In this way,
the virtual domain assignment can be useful in prevent unnecessary inter-school WCS traffic, especially
traffic whose nature might be based more upon curiosity rather than actual need.
Note
WCS user groups assign what actions a user can take against a resource, whereas WCS virtual domains
determine what resources those user group actions can be applied towards.
There are two basic steps necessary to enable the use of virtual domains within WCS:
Note
1.
A virtual domain must be created, and the resources that we wish to include assigned to the virtual
domain. The process for creating and assigning network resources to the virtual domain is detailed
in Chapter 20 Virtual Domains of the WCS Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0virtual.html#wp1040
002).
2.
The virtual domain must be assigned to the user. The process for assigning a virtual domain to a user
is detailed in Chapter 7 Managing WCS User Accounts
(http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0manag.html#wp1097
733).
It is important to note that in release 6.0, non-root WCS virtual domain users cannot access WCS
functions listed under the Services > Mobility Services main menu heading. This includes wired switch
and device location. Refer to Understanding Virtual Domains as a User, WCS Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0virtual.html#wp1120787)
for a complete list of WCS functions that are not available in non-root virtual domains.
In Release 6.0, since wired devices attached to context-aware Ethernet switches are displayed using
Services > Mobility Services > Context Aware Service > Wired > Wired Clients, only users that are
assigned to the root virtual domain are able to display context-aware information for these devices.
Figure 6-12, Figure 6-13, and Figure 6-14 demonstrate the effectiveness of WCS virtual domains (note
that the current virtual domain in use by the logged-in WCS user is highlighted in each figure by the red
oval). In Figure 6-12, we can see from the left hand margin that the root virtual domain user can see the
entire set of schools comprising the Unified School District, and is capable of applying any of the WCS
functionality accorded to them by their WCS user group assignment. This virtual domain setting might
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be appropriate, for example, in the case of a person requiring the ability to view and potentially take
action upon all resources in the network. An example of a person in a school district that might require
such capability could be a school district administrator.
Figure 6-12
Virtual Domain for Entire School District
In contrast, Figure 6-13 and Figure 6-14 each illustrate how the user's view of the school district in WCS
can be severely curtailed when a WCS virtual domain is applied. A virtual domain setting such as this
might be appropriate for most of the personnel within a school that might only need to work with school
resources located in their school only. Figure 6-13 illustrates what a user in High School #1278 would
see if they were assigned a WCS virtual domain that limited their resource visibility to only those
resources associated with High School #1278.
Figure 6-13
Virtual Domain Limited to High School 1278
In Figure 6-14, we see the results of a WCS virtual domain for a user in Elementary School #1266. Note
that a user that is assigned a virtual domain for school 1266 does not have visibility to any resources
associated with other schools. All that is visible to the school 1266 user in this case are the buildings and
floor maps associated with school 1266.
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Figure 6-14
Virtual Domain Limited to Elementary School 1266
Figure 6-15 illustrates the typical result that occurs when a user attempts to view information for
resources outside the scope of their assigned virtual domain. In this case, we see the result of a user in
school 1266 attempting to access resources in another school, #1278.
Figure 6-15
Virtual Domain Permission Error
Mobility Services NMSP Parameters
WCS 6.0 provides us with several NMSP parameters available that affect various NMSP protocol timing
characteristics between the MSE and its session partners. These parameters can be found at Services >
Mobility Services > System > NMSP Parameters, and apply globally to all NMSP sessions between
the selected MSE and any of its WLAN controller or Ethernet switch session partners. Complete
configuration information for configuring NMSP session timing parameters, as well as the default values
for these parameters, can be found at Configuring Mobility Services Engine Properties section of the
Context-Aware Service Configuration Guide
(http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch4_CAS.
html#wp1014368).
When deploying an MSE locally in the school, it is unlikely that these parameters will require changes
from the default values, except perhaps in the very largest of schools where there might be several
thousand tracked devices, and a large quantity of wireless devices moving about on a regular basis.
However, in a centralized deployment, there is more of a chance that network congestion or other factors
may cause delays that could cause NMSP session timeouts. While this should be minimized by the
appropriate identification and classification of NMSP data flows in the network along with properly
defined network QoS, there may be instances where adjustments to NMSP timing is required. In these
cases, the NMSP echo interval, neighbor dead interval, and response timeout values can be increased to
limit the number of failed echo acknowledgments that may occur, especially in a centralized MSE
deployment.
Note
Readers are advised that a tremendous amount of functional validation was performed in association
with the content contained in this chapter. However, time constraints limited the degree of performance
validation that could be completed for Context-Aware Services across a simulated Metropolitan Area
Network (MAN). The deployment of Mobility Services Engines in a centralized fashion across a MAN
was not able to be fully validated due to these time constraints. We hope to revisit and validate
centralized deployments of context-aware services over a MAN at a future time.
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To aid in determining whether echo packets are being dropped, you can use the WCS function Services
> Mobility Services > System > Status > NMSP Connection Status as shown in Figure 6-16. This
WCS menu panel displays all the NMSP session partners for this MSE, along with echo request and
response counts. For example, in the figure for the Mobility Services Engine with the hostname MSE1,
we see that there are currently two NMSP sessions to two different school WLAN controllers.
Figure 6-16
NMSP Connection Status
We can see in Figure 6-16 that both of the NMSP WLAN controller sessions appear to be functioning
properly, as the number of Echo Requests issued is seen to be exactly equal to the number of Echo
Responses received. This might not always be the case and small static differences over a long period of
time do not necessarily indicate a serious problem. However, sluggish performance combined with a
regularly increasing discrepancy in the delta between the number of requests issued and responses
received could be indicative of the NMSP session timing out. In a centralized deployment, this may be
due to unforeseen levels of congestion or other resource constraint. In this case, raising the response
timeout may assist in alleviate the timeouts. Keep in mind, however, that a successful centralized
deployment assumes that there is sufficient MAN capacity available to each school and that QoS has
been applied appropriately.
Figure 6-17 gives an example of the NMSP Parameter screen that is located at Services > Mobility
Services > System > NMSP Parameters, which we can use to change the system defaults. In
Figure 6-17, the network administrator or network technician has instituted the following changes from
the defaults: the echo interval has been raised to 30 seconds, the neighbor dead interval has been raised
to 60 seconds, and the response timeout has been raised to 5 seconds.
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Figure 6-17
Note
Example of NMSP Parameter Modification
Although the NMSP configuration worked well for us in our lab testing, we cannot predict and simulate
each and every condition that might occur in a production deployment. Therefore, it is important that
you take the time to understand the function of these parameters and especially the fact that they can be
adjusted beyond the values illustrated here in order to promote improved NMSP session stability and
network performance.
Further information on these NMSP parameters can be found in the Configuring Mobility Services
Engine Properties section of the Context-Aware Service Configuration Guide
(http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch4_CAS.
html#wp1014368).
Context-Aware Service Parameters—Tracking
As mentioned earlier, Context-Aware Services can track up to a maximum of 18,000 licensed devices
when using the MSE-3350 hardware platform, and up to a maximum of 2,000 licensed devices when
using the MSE-3310 platform. The absolute limit on the number of clients or tags that can be tracked is
determined by the hardware platform used, the presence of any other applications co-residing on the
MSE, and the level of licensing purchased. The WCS tracking parameters configuration panel (located
at Services > Mobility Services > Context Aware Service > Administration> Tracking Parameters)
allows the administrator to pre-determine just how much of the MSE's maximum licensed tracking
capacity will be allocated towards the tracking of specific device categories. This is useful in the Schools
SRA environment in order to allow the tracking of device categories such as nearby rogue access points
and rogue clients, but also limit these categories such that an uncontrolled introduction of rogues is not
allowed to consume all of the remaining context-aware tracking capacity on the MSE.
We can use the Context-Aware Service Tracking configuration to:
•
Entirely enable or disable the tracking of wired and wireless client stations, asset tags, rogue access
points, and rogue clients.
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•
Set limits on how much MSE tracked device capacity will be allocated to certain device categories.
Figure 6-18 provides us with an example of how this can be achieved, where the maximum number
of tracked clients and rogue clients/APs are capped at 4,000 devices each. No limit is placed on the
number of RFID tags tracked, which in effect means that the maximum number of tags tracked will
be allowed to rise until the tag licensing limit is reached (3,000 tags).
Note that any devices that are detected but excluded from tracking due to the enforcement of a tracking
limit will be reflected in the “Not Tracked” device count column shown on the right side of the display.
Figure 6-18
Note
Context-Aware Service Tracking Parameters
In Release 6.0, wired client tracking can be enabled or disabled, but imposing a limit on the number of
wired clients that are tracked simultaneously is not supported at this time. As a workaround, use switch
CLI commands such as the global nmsp disable or the interface nmsp suppress attachment commands to
limit the number of tracked wired clients that are presented to the MSE.
Context-Aware Service Parameters—History
The MSE records and maintains historical location and statistics information for wireless clients, tags,
rogue access points, and rogue clients. This information is available for viewing through WCS or via
third-party context-aware application clients, and can be very valuable in helping establish patterns of
movement for tracked assets and rogues. Historical information can be used for location trending, asset
loss investigation, RF capacity management, and facilitation of network problem resolution. Contextual
information such as whether an emergency button was depressed or whether an asset tag has moved into
close proximity to a chokepoint trigger is also tracked in the history data.
The collection of historical information must be explicitly enabled for each desired category of device
(as shown in Figure 6-19). By default, 30 days of historical data are stored in the MSE.
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Figure 6-19
MSE History Parameters
There are several variables that can affect how much historical information can be stored by the MSE for
the tracked assets in your school or school district. Among these variables are the average number of
elements that move, average distance covered every time there is a movement, information transitions,
telemetry information from tags, and so on. Depending on these variables as well as the number of items
for which you are tracking history information in your school, you may wish to decrease the number of
days of historical data to a value below 30 days.
Changes to the default history archive period should be done with careful consideration, since longer
history periods typically increase the amount of space consumed by the history database. Users
unfamiliar with the way in which Context-Aware Services on the Cisco MSE archives historical
information for tracked devices may wish to consult with your Cisco field technical representative or the
Cisco Technical Assistance Center
Figure 6-20 illustrates what you can expect to see when recalling the history for a tracked device. Here,
we recall the history for a specific WLAN client. As shown in Figure 6-20, the focus of the display is
the list of past locations recorded for the client. Setting the “change selection time” parameter on the
screen and then clicking play displays the various client locations on the small floor map at the right side
of the image (this can be enlarged for easier viewing). In this way, you can step back through all of the
stored locations for the client within the history database. Obviously, this information could be very
useful to school administrators, district and school WLAN engineers, as well as school resource officers
and other law enforcement officials that may be looking for information useful in recreating a sequence
of events that may have take place in the past.
Figure 6-20
Display of Location History for a WLAN Client in the School
Further information on the procedure to follow when making adjustments to history parameters can be
found in the following documents:
•
Context Aware Solution Deployment Guide
http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml#rfid
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•
Context Aware Service Configuration Guide 6.0
http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch7_C
AS.html#wp1128896
Context Aware Service Parameters—Notifications
Cisco WCS allows you to define certain conditions for tags, WLAN clients, and rogues that cause the
MSE to send notifications to application programs that are monitoring specific ports. You can use Cisco
WCS to define and enable both conditional notifications and northbound notifications.
Conditional notifications are those notifications that the mobility services engine sends to Cisco WCS
and other applications that can receive short, relatively simple messages via SOAP/XML (either HTTP
or HTTPS), SMTP, UDP Syslog, or as an SNMP trap. Conditional notifications can be triggered by
WLAN clients, tags, or rogue devices. The conditions available include:
•
Missing—The MSE generates a Missing Asset conditional notification if it has not located the asset
for more than a specified number of minutes.
•
In/Out—The MSE generates an In/Out conditional notification if the asset is found to be inside of,
or outside of, a selected area.
•
Distance From Marker—The MSE generates a Distance From Marker conditional notification if the
asset is found to be beyond a specified distance from a designated marker.
•
Battery Level—The MSE generates a Battery Level conditional notification if the battery level
reported by an asset tag is equal to a selected value.
•
Location Change—The MSE generates a Location Change conditional notification if the asset
experiences a change in location.
•
Emergency—The MSE generates an Emergency conditional notification if a tag button, tamper or
detached event is detected.
•
Chokepoint—The MSE generates a Chokepoint Conditional notification if a tag enters into the
proximity of a chokepoint trigger.
Northbound notifications are a special category of notification that is specific to RFID tags only. They
define which tag notifications the MSE will send to third-party applications using SOAP/XML.
Northbound notifications can include chokepoint, telemetry, emergency, battery, and tag vendor data.
Optionally, the tag's location coordinates can be included within the northbound notifications as well.
An important difference between conditional notifications and northbound notifications is that
northbound notifications can contain considerably more information. The information sent in the
northbound notification is sent in a pre-defined data format. Details regarding the data format for
northbound notifications are available on the Cisco developers support portal at
http://developer.cisco.com/web/contextaware.
Note
In Release 6.0, neither conditional nor northbound notifications can be applied to tracked wired devices.
Complete and detailed information regarding how to configure Context-Aware Notifications can be
found in the following locations:
•
Configuring Event Notifications chapter of the Context-Aware Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch6_C
AS.html).
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•
Enabling Notifications and Configuring Notification Parameters section of the Context-Aware
Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch7_C
AS.html#wp1129909).
•
Context-Aware System Performance section of the Context-Aware Solution Deployment Guide
(http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml#casy
sperf).
Via the menu panel located at Services > Mobility Services > Context Aware Service > Advanced>
Notification Parameters (Figure 6-21),WCS allows the user to modify several advanced timing
parameters pertaining to conditional notifications and northbound notifications. For example, you can
limit the rate at which the MSE generates notifications, set a maximum queue size for notifications, and
set a retry limit for notifications with in a certain period.
Figure 6-21
Note
Context Aware Advanced Notification Parameters
Modify advanced notification parameters only when you can reasonably expect the Mobility Services
Engine to transmit a large number of notifications or when it is noticed that notifications are being
dropped.
•
Rate Limit—(Pertains to northbound notifications only.) This is the rate in milliseconds at which the
MSE generates northbound notifications. A value of 0 (default) means that the Mobility Services
Engine generates event notifications as fast as possible. If you are using the northbound notifications
system to communicate to a third-party application (such as AeroScout MobileView, for example)
in the Schools SRA, it is recommended that you consider how often notifications are expected to be
generated and how many total notifications will be requested of the MSE per minute. For example,
an exception based notification (such as an emergency notification) is not a normal event and thus
it would be extremely unusual to see a great deal of emergency events generated from many schools
at the same time. However, a more routine event, such as the chokepoint entry event that would be
used in a parent curbside pickup application, could be expected to generate much more traffic
during, for example, the hours of 2:00-2:30 PM, when a large number of parents might be expected
to pick up children from a suburban school district. In cases such as this where a large number of
notifications might be a normal and routine event, it is recommended to increase the rate limit so as
to allow the MSE to pace the transmission of notifications (for example, a rate limit value of 200
would slow the rate of notification transmission down to one every 200 msec). The correct
notification delay will vary from deployment to deployment depending on the amount of traffic
generated.
•
Queue Limit—Specifies the size of the output notification queue of the MSE. Default queue limit
value for the MSE-3350 is 18000 and for the MSE-3310 it is 5,000. The MSE drops any outbound
notifications above this limit if the output notification queue size is exceeded. In the School SRA
design, if you are using context-aware notifications, it is recommended that you use the Queue Limit
parameter in conjunction with the Notifications Dropped counter to avoid any notifications from
being dropped. If you notice that the Notifications Dropped counter is greater than zero, you should
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consider increasing the Queue Limit parameter to avoid any future increases. Given the relatively
large default sizes for this parameter however, it is unlikely that adjustment will be required except
in rare cases where very many notifications are generated.
•
Note
Retry Count—For each matching condition, the retry count specifies the number of times to generate
an event notification before the refresh timer expires. The default value is 1. The total number of
event notifications transmitted between Refresh Time periods is equal to one plus the value specified
for Retry Count. After the value of one plus the Retry Count has been reached, the location appliance
skips firing any further northbound notifications for this condition and device for the time period
specified by the Refresh Time. Once the Refresh Time has expired, this cycle repeats unless the
event has been cleared. Retry count is intended to help ensure (to a limited extent) that notifications
reach their intended destination. If notifications are not indicated as being dropped by the
Notifications Dropped counter, but are not reliably reaching their destination application, you may
wish to increase the number of notifications sent between Refresh Time periods by raising the Retry
Count judiciously.
The Mobility Service Engine transmits notifications using a “Fire and Forget” technique. Notifications
are not retained in any database within the MSE after they are transmitted.
•
Refresh Time—The wait time in minutes that must pass before an event notification is resent. The
default is 60 minutes. Refresh Time and Retry Count are used cooperatively to help limit the number
of notifications repeatedly generated for events that have not been cleared. Retry Count limits the
number of notifications that are sent by the MSE, while Refresh Time imposes a “waiting period”
during which time no further notifications are sent for this event condition and device. If you are
noticing that repeated notifications are being generated for the same event, it may be due to the
condition not clearing within the refresh time interval. In this case, you may wish to investigate why
the triggered condition does not clear and possibly extend the refresh time.
•
Notifications Dropped—The number of event notifications dropped from the queue since startup.
The Notifications Dropped counter should be used in conjunction with the Queue Limit parameter
to reduce the number of total dropped notifications.
WLAN Controller and Ethernet Switch Definition and Synchronization
To allow for proper tracking of the devices that may be registered or attached to them, WLAN controllers
and context-aware Ethernet switches must be defined to WCS and then synchronized with the Mobility
Services Engine.
Detailed information regarding how to add WLAN controller definitions to WCS using the WCS
Configure > Controllers menu panel can be found in the section entitled Adding Controllers in the WCS
Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0ctrlcfg.html#wp1041451)
.
Detailed information regarding how to add Ethernet switch definitions to WCS using the WCS Configure
> Add Ethernet Switches menu panel can be found in the WCS Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0ctrlcfg.html#wp1089752)
.
Detailed information regarding how to synchronize the MSE with WLAN controllers and context-aware
Ethernet switches using the WCS Services >Mobility Services > Synchronize WCS and MSE(s) menu
panel can be found in the Synchronizing Mobility Services Engines chapter of the Context-Aware
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Service Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch3_CAS.
html#wp998995).
Note
Always ensure that the MSE is synchronized with the primary WLAN controllers it is providing
Context-Aware Services for, as well as any backup WLAN controllers in the Schools SRA design. If the
MSE is not kept in synchronization with your backup WLAN controllers, Context-Aware Services may
not function properly or may not be available at all for WLAN clients and RFID tags in the event of a
primary WLAN controller failure.
Wireless Client Context-Aware Considerations
The ability to track WLAN client location using Cisco Context-Aware Services can be useful in a school
to locate WLAN clients that are part of our school network (such as authorized 7921G and 7925
VoWLAN phones, laptops, wireless desktops, etc.). Generally speaking, provided that a 802.11 wireless
client device has its 802.11 wireless network interface adapter powered on and is sending periodic
transmissions (probe requests), these WLAN client devices can be located by Context-Aware Services.
Since devices such as portable VoWLAN phones are very often powered on for the entire day and carried
on the belt, purse, or pocket of the user, these devices become useful in helping locate not only the device
itself but the user to which the device is assigned. As the device becomes larger in size and heavier in
weight, we find that the chances of the device being with the assigned user all the time diminishes and
thus its usefulness as a way to determine the location of the user diminishes as well.
Tracking WLAN client devices by their wireless network interface adapter works well if the goal is to
track the location of the device when it is in operation and use this information to enhance the operation
of the device on the network, or its interaction with an application. For example, using WLAN client
tracking in the school environment to perform one or more of the following represents a prime example
of how this functionality can be put to use in the school environment:
•
Determining where wireless users and their portable devices may congregate, allowing for the
placement of access points to be further optimized to enhance overall coverage and performance.
•
Investigate where a missing device is currently located within the school or district campus. A good
example might be when equipment is “borrowed” from one classroom to another (or even from one
school to another) without permission.
•
Determining the location of users that are known to be visiting guests, and helping ensure that they
do not stray into areas that have been explained to be off-limits to them.
•
Using the location history of a wireless device to establish a pattern of usage and location in order
to clarify past actions, such as any past actions that might relate to safety and security concerns.
•
Use the location of wireless LAN clients as a parameter for network troubleshooting and security
audits.
•
Use the location of wireless printers (or other output devices) as input to an application designed to
determine which device is available and most convenient for a particular wireless user depending on
the user's location.
Figure 6-22 illustrates how Cisco Context-Aware Services can be used with Cisco WCS to display the
current location of school faculty members equipped with Cisco 7925G IP phones, laptops, and PDAs
in a sample lab school environment. Note that we have chosen to assign and display the user name
associated with each device, rather than the device MAC address. Clicking on any of the blue WLAN
client icons shown in Figure 6-22 displays a plethora of information about the client device, including
its client properties, association history, connection troubleshooting information, as well as its event
history.
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Figure 6-22
WLAN Client Tracking
If the intention is to try and track a wireless device for inventory or loss prevention purposes, it is
important to ascertain whether the embedded network interface remains active for any devices that may
be in a powered-down or standby state. Even so, if the device remains active but accesses the network
only very infrequently in order to conserve power, the degree of location fidelity obtained will likely be
less than optimal, especially if the device can be expected to move frequently while in this state. A higher
accuracy solution for this type of full-time location tracking application would be to attach or embed a
RFID asset tag (see RFID Asset Tag Context-Aware Considerations) to the device. RFID tags are
independently powered and operate without concern for the power state of the WLAN client device, and
can be stimulated to transmit immediately when passing in proximity of properly equipped doorways
and exits.
In general, best results are obtained in context-aware designs when all WLAN clients are compliant with
the Cisco Compatible Extensions for WLAN Clients specification v2 at minimum, and preferably with
the Cisco Compatible Extensions for WLAN Clients specification v4 or v55.
Additional information on the Cisco Compatible Extensions program for Wi-Fi Client Devices is
available at http://www.cisco.com/web/partners/pr46/pr147/partners_pgm_concept_home.html.
Note that this document does not detail the steps involved with important procedures such as calibration
of the Context-Aware Engine for WLAN Clients, or the definition of location inclusion and exclusion
regions and other deployment procedures. For information on these and other procedures that should be
understood prior to deployment, refer to the MSE Context Aware Service Deployment Guide
(http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml).
5. Readers interested in the technical details concerning compatibility with the Cisco Compatible Extensions for
WLAN Clients specification v2 are referred to the section entitled Tracking Clients, Assets and Rogue Devices
in Wi-Fi Location Based Services Design Guide 4.1,
http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/wifich3.html#wp1049277
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Intel® Wi-Fi Clients and ProSet Client Supplicant Context-Aware Considerations
When using clients equipped with the Intel® Wireless WiFi Link 4965AGN, Intel® PRO/Wireless
3945ABG Network Connection, or the Intel® PRO/Wireless 2915ABG Network Connection adapter, it
is important to note that the default “Personal Security” settings of the Intel® ProSet Configuration
Utility does not include compatibility with the Cisco Compatible Extensions specification. In order to
enable compatibility with the Cisco Compatible Extensions specification, the Intel ProSet client
supplicant must be used to reconfigure the client for “Enterprise Security” and to enable Cisco
Compatible Extensions using the “Cisco Options” (Figure 6-23).
Figure 6-23
Enabling Cisco Compatible Extensions on Intel® ProSet Clients
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Cisco 7921 and 7925G Context-Aware Considerations
7921G and 7925G Unified IP Wireless Phone users should note that phones that are idle and not
currently participating in an active call may not transmit 802.11 Probe Requests with sufficient
frequency to ensure that changes in the actual location of the phone user are promptly reflected in the
calculated location coordinates provided to the contest-aware services software in the MSE. In some
cases this can be of concern, especially if the 7921G or 7925G user remains within the primary coverage
area of the same access point for long periods of time. In cases where an access point might have a large
coverage footprint, a roaming event may not occur very often despite a significant change in user
location.
If you experience situations where the location fidelity of a 7921G or 7925G Unified IP Wireless Phone
appears to be much better for those users actively participating on a call versus those that are on hook
and idle, you may wish to consider changing the scan mode parameter associated with the 7921G or
7925G device in the Cisco Unified Communications Manager. In some cases, improved location fidelity
can be achieved by enabling the “continuous” scan mode on the Device=>Phone configuration page of
Cisco Unified Communications Manager Administration (shown in Figure 6-24). Note that scan mode
options listed are “auto”, “continuous”, and “single AP”, where auto is the default. “Continuous” scan
mode causes the wireless IP phone to issue a probe request approximately every two seconds, whereas
“auto” scan mode causes the device to issue probe requests primarily only when the device is engaged
on an active call, when roaming, or when preparing to roam. “Single AP” is used in installations where
the wireless IP phone is only used in the vicinity of a single access point at all times, as probe requests
are issued only when the wireless IP phone is first powered on. “Single AP” mode is not applicable and
should not be used in the Schools SRA design.
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Figure 6-24
Note
Scan Mode Option in Cisco Unified Communications Manager
It is recommended that continuous scan mode be used only in situations where the anomaly described
here is actually witnessed. This is because a trade-off associated with any increase in the frequency of
probe requests transmitted is the potential for reduced 7921G or 7925G battery life. If you do not notice
the anomaly described in this section, it is recommended that you leave the CUCM scan mode setting at
the “auto” default.
RFID Asset Tag Context-Aware Considerations
Radio Frequency Identification (RFID) has many potential safety and security applications in the
education arena. Already used in various enterprise sectors, from the logistics depot that tracks pallets
of goods throughout the warehouse, to the motorist with the “EZ-Pass” or “CruiseCard” that no longer
needs to search for change at the toll booth, schools can now embrace RFID technology to address a wide
realm of challenges.
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Figure 6-25
Floor Map Showing Various Uses for RFID Tags and Cisco Context-Aware Services
The illustration in Figure 6-25 provides us with a visual representation of just some of the ways RFID
can be used in the Schools SRA in conjunction with Context-Aware Services:
•
High value assets (such as projectors, microscopes, telescopes, audio/video equipment, etc.) can be
kept safe and secure, since the application of RFID tags to these assets provides school
administrators and school resource officers with the ability to locate the assets quickly and
efficiently. Figure 6-25 illustrates how the present location of assets equipped in this fashion can be
quickly ascertained by a quick check of the school floor map. Here we can see the last known
location of a lab centrifuge, microscope, telescope, portable PA system, XVGA projector, and even
a mass spectrometer. For buildings containing more than a single floor, database search techniques
can be used to search for the desired asset by name or attached RFID tag MAC address.
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Figure 6-26
ID Badge with Embedded Active RFID
•
Faculty and administrators can wear specially manufactured badges (see Figure 6-26) that combine
a traditional identification card with active RFID technology, allowing them to be located quickly
in the event of an emergency. These same devices can also transmit special notifications using a push
button sequence, which can be interpreted in various ways by Context-Aware Services, including as
a signal that an emergency event is in progress. Figure 6-25 illustrates how a person can be located
if they are carrying an RFID-enabled ID card, as seen in the displayed location of the school’s
resource officer (a law enforcement official), whose location is currently indicated as being inside
of the school principal’s office. Being able to physically locate the school resource officer using a
tool such as this could help in saving precious seconds in the event of a school emergency.
•
The whereabouts of school visitors (such as maintenance or repair contractors) can be monitored
and alerts triggered to school resource officers and others if these visitors stray into areas that they
have no authorization to be in. For example, in Figure 6-25, we see that in our school we have an
HVAC repair contractor as well as a visiting parent. In addition to making us aware as to the
presence of these visitors, our system can alert us if these personnel access areas that we do not want
them to by comparing their current locations to location boundaries we have defined as notification
rules. Third-party applications that can access context-aware information from the MSE may
perform more advanced tasks as well.
•
RFID tag technology can be combined with chokepoint triggers (Exciters) to enable the use of
proximity applications. In this fashion, chokepoint triggers can serve many purposes, including
stimulating asset tags affixed to assets that might be in the process of being removed from the school
building without authorization. This makes it possible to notify school officials or resource officers
of such action, so as to act quickly and determine whether such movement is legitimate.
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Figure 6-27
•
Curbside Congestion at a Typical Urban School
The concept of a curbside student receiving application in a suburban school system that notifies
student hallway monitors and school faculty assistants when a parent has entered school property,
ready to pick up their child at the end of the school day. By issuing the parent an RFID tag that is
serialized and known to the context-aware system, safety, security, and efficiency is increased.
School personnel are aware that the parent's vehicle has entered school property and is waiting in
the queue for their child. Children can be retrieved from waiting areas and classrooms in an efficient
manner, and presented to parents that are in queue at the school front entrance. This reduces school
curbside congestion (see Figure 6-27), gets parents and students in and out of the school area
quickly, and reduces the amount of pollutants emitted by idling vehicles waiting in line for curbside
pickup and drop off.
An RFID tag whose MAC address has been recorded and registered with Context-Aware Services
as to being issued to a particular parent and vehicle is shown in Figure 6-25. In Figure 6-25, we see
that the arrival of a young student’s mother (“Mrs. Wisnewski”) is signified by the appearance of
an RFID tag assigned this label at the location of the chokepoint trigger installed at the school
driveway entrance. Even more importantly, the lower portion of Figure 6-25 provides a conceptual
illustration of how Cisco Context-Aware Services can generate a SOAP/XML notification to a
receiving application (“Parent Pickup: Johnny Wisnewski”). The receiving application then could
be used to trigger visual and audible notification in the school that this child’s parent has arrived
and that the child should be brought forward and queued for release. As each parent vehicle in a long
stream of cars enters the school driveway and takes its place in the queue, school personnel are made
aware that the parent is only a few hundred yards away and will soon be at the curbside front door
pickup area to pickup their child. This system can help manage this process and drastically increase
the ability of limited school resources to dispatch those children to those parents that prefer to drop
off and pick up their children each day.
In addition to simply displaying the location of assets, Cisco Context-Aware Services makes other
contextual characteristics of the asset and its environment available to applications accessing the
MSE via its SOAP/XML API. For instance, if the asset tags used contain on-board temperature
sensors, we can also read the current temperature surrounding the asset tag via the MSE. This can
be seen in Figure 6-28, where we see from WCS that the ambient temperature surrounding our
HVAC repairman is 20 degrees Celsius or a comfortable 68 degree Fahrenheit. Looks like our
school air conditioning system is doing its job from what this tag sensor tells us. It is important to
note that while WCS is used to view this information in Figure 6-28, any authorized context-aware
application that is written to use the MSE SOAP/XML API could have accessed this data as well.
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Figure 6-28
Rogue AP Details
Simply put, RFID technology and Cisco Context Aware Services can help schools improve their overall
safety, security, and efficiency.
Cisco Context-Aware Software is designed to function with active RFID asset tags from vendors
compliant with the Cisco Compatible Extensions for Wi-Fi Tags specification. A list of current Cisco
Compatible Extensions for Wi-Fi Tags compliant vendors can be found at
http://www.cisco.com/web/partners/pr46/pr147/ccx_wifi_tags.html. Although all vendor RFID tags
compliant with the Cisco Compatible Extensions for Wi-Fi Tags specification share a great deal of
functionality in common, the parameter names and means used to configure each brand of tags can differ
from vendor to vendor, therefore no set prescribed configuration parameter list would apply to all. That
being said, there are several general configuration functions that tag vendors share and although the
exact parameter names may differ, it is important that you understand them and use this knowledge
accordingly when configuring the particular tags of choice for your installation. More information
regarding the configuration procedure for AeroScout tags can be found in the section entitled RFID Tag
and WLC Configuration/Tuning in the Cisco MSE Context-Aware Deployment Guide
(http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml#rfid-wlc)
6
.
•
RF Channel Configuration—It is recommended that tags be configured for the standard set of 2.4
Ghz non-overlapping channels, which is typically channels 1, 6, and 11 (this may vary depending
on your international regulatory domain).
•
Stationary Transmission Interval—This is the time between periodic tag transmissions that are
normally generated when the tag is stationary and not in motion. It is recommended that this be
configured for values between 3 and 5 minutes.
6. Additional information can also be found in the Wi-Fi Location-Based Services Design Guide 4.1 section
entitled Configuring Asset Tags, located at
http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/wifich6.html#wp1077248.
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•
Motion Transmission Interval—(Applies only to tags with motion sensors.) This is the time between
periodic tag transmissions generated when the tag and asset is in motion. A recommended initial
value is 15 seconds.
•
Number of Tag Message Repetitions—Some popular RFID tags default to transmitting a single
transmission on all defined channels. Tag parameters that control the number of tag message
repetitions specify the number of times each transmitted message is repeated, per channel. It is
generally recommended that this parameter be set to a value of three. Doing this helps protect
against lost tag transmissions due to congestion or interference, which is a primary cause of poor
tag location accuracy.
•
Message Repetitions Interval—The delay between subsequent message repetitions on the same
channel. This is often defaulted to 512msec, although in lab testing we have seen some evidence of
improved location accuracy when a message repetition interval of 256 msec is used with the default
controller value of 2 seconds for NMSP notification interval. This parameter is discussed in more
detail the section entitled RFID Tag and WLC Configuration/Tuning of the Cisco MSE
Context-Aware Deployment Guide
(http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml#rfidwlc).
This chapter does not detail the steps involved with procedures such as calibration of the Context-Aware
Engine for Tags and other deployment procedures. For information on these and other procedures that
should be understood prior to deployment, refer to the MSE Context Aware Service Deployment Guide
(http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml). In
addition, the AeroScout Context-Aware Engine for Tags for the Cisco MSE Users Guide, version 3.2,
available from your AeroScout representative or https://support.aeroscout.com, is highly recommended.
RFID Tag Chokepoint Trigger Considerations
Chokepoint triggers are proximity communication devices that trigger RFID asset tags to alter their
behavior when the tag enters into close range (otherwise known as the stimulation zone) of the
chokepoint trigger. This behavioral modification may, for example, cause the RFID tag to immediately
transmit its unique identifier (MAC address) or cause the tag to change its internal configuration,
depending on how the tag is programmed. A very popular use of the chokepoint trigger is to stimulate
the asset tag such that it provides indication to the MSE that the tag has entered or exited a given area,
known as a chokepoint. Chokepoints are entry or exit points that provide passage between connected
regions. Common chokepoints are entrances and exits such as doorways, hallways, and stairwells.
Note
An Exciter is a registered trademark of AeroScout Ltd., and represent a popular example of a chokepoint
trigger.
In schools, chokepoint triggers are useful in causing RFID tags to react quickly when assets are moved
past certain points in the school. This could be a microscope with an affixed RFID tag moving past a
chokepoint trigger located near a school exit, a faculty member with an RFID badge walking into the
school through the front entrance at 7:00 AM, or it could be a parent in the family automobile that has
a RFID tag on the front visor coming past a chokepoint trigger located at the entrance of the school
property. In all these cases, the chokepoint trigger causes the tag to change its behavior, most likely to
immediately transmit its MAC address (as well as the MAC address of the chokepoint trigger that
stimulated it) to the MSE via one or more access points that can receive the tag's transmissions. The net
result is to cause the MSE to indicate that the current location of the asset and its asset tag is within a
known, pre-determined proximity of the chokepoint trigger.
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In order to use chokepoint triggers with Cisco Context-Aware Services, they must be properly configured
using the appropriate vendor-supplied software utility, defined to WCS, placed on floor maps, and
synchronized as part of an updated network design to the MSE. After all of this is complete, the MSE is
able to recognize the transmissions generated by asset tags that have been stimulated by specific
chokepoint trigger MAC addresses. Based on this information, the MSE can attempt to localize the tag
to the proximity of the chokepoint trigger. Applications such as WCS (or third party context-aware
applications) may then display the asset tag's location at the chokepoint icon associated with the
chokepoint trigger's MAC address.
Various chokepoint trigger specific parameters such as transmission range, IP address, transmission
interval, transmission repetitions, and so on are set using vendor-specific utilities. Note that each vendor
maintains their set of software tools necessary for configuration of their chokepoint triggers. These
software configuration tools are not interoperable between vendors (for example, AeroScout software
configuration tools cannot be used to configure WhereNet chokepoint triggers or vice-versa).
The individual configuration of each vendor's chokepoint trigger is beyond the scope of this chapter.
Complete and detailed configuration information relating to the specific configuration of each vendor's
chokepoint trigger can be found in the appropriate vendor's documentation, which can be obtained from
your tag vendor representative.
AeroScout EX-3200 User Guide https://support.aeroscout.com
AeroScout Exciter EX-2000 User Guide https://support.aeroscout.com
AeroScout Context-Aware Engine for Tags for the Cisco MSE Users Guide, version 3.2
https://support.aeroscout.com
Technical documentation for WhereNet WherePort chokepoint triggers and the necessary software and
hardware for configuration of WherePorts is available from WhereNet Corporation
(http://www.wherenet.com) or via your WhereNet account representative.
Rogue Device Context-Aware Considerations
The use of context-aware services for locating clients and RFID tags that we have defined and authorized
in the school environment is often what first comes to mind for many of us when we consider this
solution. However, another equally important and useful function of context aware services is the ability
to detect the location associated with those wireless clients and access points that we have not authorized
to operate within our domain. In other words, context-aware services in our schools can help us in
locating rogue access points or rogue clients that may have been installed within our school by students,
contractors, visitors, vendors, or even faculty or administration members without authorization. Even if
an unauthorized access point is innocently installed by a school user that is otherwise authorized to use
the school network, the unauthorized and potentially insecure portal provided by such an access point
can unnecessarily expose our secure school network to outside intruders.
The Cisco Wireless Control System can use the location capabilities provided by the Cisco Mobility
Services Engine and the Cisco Context-Aware Engine for Clients to define the location of unauthorized
access points and the wireless clients that may be using these access points, as shown in Figure 6-29. In
the figure, we can see icons for both rogue access points as well as rogue clients displayed over their
predicted positions on a floor map of an elementary school located within our school district. This
capability is very useful both to the local school administrator, as well as the district network
administrator and their technical teams. It allows them to determine the location of wireless equipment
that may have been brought into the school and used in an attempt to gain unauthorized access to school
or district computing resources. In Figure 6-29, the round icon with the “skull and crossbones” logo
represents the rogue access point and the rectangular icon with the same logo represents a rogue client
that is associated to this rogue access point.
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Figure 6-29
Note
Using Context-Aware Services to Perform Location of Rogue Access Points and
Clients
In comparison to WLAN clients and RFID tags, it is normal to experience a reduced accuracy when
localizing rogue access points and rogue clients. The very nature of “rogue” devices establishes that
these devices are not under the control of school administration. Therefore, the configuration of such
these rogue devices may not facilitate optimal context-aware location accuracy (for example, they may
not be Cisco Compatible Extensions devices, etc.).
As shown in Figure 6-30, clicking on either the rogue access point icon or the rogue client icon reveals
additional information and capabilities that can help in further identifying (and even isolating) these
devices. This includes the ability to perform switch port tracing with the latest versions of WCS, which
allows tracing of rogue access points that have been connected to the switch infrastructure (for more
information on switch port tracing, refer to the WCS Configuration Guide 6.0,
(http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0ctrlcfg.html#wp1089752)
.
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Figure 6-30
Rogue AP Details
The collection of rogue AP and rogue client information is enabled by default on WLAN controllers. In
order to enable the tracking of rogue access points and rogue clients by the context-aware service, it is
important to ensure that the collection of rogue information has also been enabled for context-aware
services on the MSE. Refer back to Figure 6-18 in this chapter and ensure that the “Rogue Client and
Access Points” tracking parameter check box has been enabled under Mobility Services >
Context-Aware Services > Administration >Tracking Parameters.
Note
Be advised that depending on the environment in which your school is located, as well as the number of
rogue devices present, the number of rogue devices detected can rise very quickly. Since the size of the
rogue device population is typically not under the direct control of school IT staff or local school
administration, it is highly advisable that you enable limiting for rogue clients and access points and set
a limiting value. This is so that any unforeseen increase in the number of rogue devices detected does
not consume all the remaining tracked device capacity on the MSE, thereby depriving the MSE of
capacity that might be of more significance to school administration and faculty. This is especially
important if the MSE is used to service more than just one school in your district.
In addition to enabling the collection of rogue access point and rogue client information by the
context-aware services on the MSE, you must also enable the display rogue device location when
displaying floor maps using WCS. This is accomplished via the WCS “Floor Settings” submenu that is
displayed on every WCS floor map, as shown in Figure 6-31. Information on how to use the Floor
Settings sub-menu for all the categories of device shown here can be found in Chapter Five of the WCS
Configuration Guide 6.0,
http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/6_0maps.html#wp1210969.
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Figure 6-31
WCS Floor Settings Sub-Menu
For further information regarding rogue access points and clients, refer to the following documents:
•
Context Aware Service Configuration Guide 6.0
http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/CAS_60.html
•
Cisco Wireless Control System Configuration Guide, Release 6.0
http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/WCS60cg.html
•
Cisco MSE Context Aware Deployment Guide
http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml
Context-Aware Considerations for Wired Device Tracking
As described previously in this chapter, beginning with release 6.0 Cisco Context-Aware Services
provides the capability to determine the civic location and emergency line identifiers of devices
connected to Cisco Catalyst switches, such as the 2960G, 3560E, 3750E, 3750G, 4500, and 4900 series.
As participants in context-aware services, switches are configured with and provide the relevant
contextual information for all the IP endpoints attached to them. These endpoints may include IP phones,
PCs, host servers, access points, etc. The NMSP protocol is used between the switches and MSE to
deliver this contextual information to the MSE. Location information may include the physical location
address (also known as the civic address) as well as other information about endpoints such as the IP
address, MAC address, port, VLAN, and username. If the end device makes use of the Cisco Discovery
Protocol or Link Layer Discovery Protocol (LLDP), additional information, such as the version number
and serial number, can also be sent to the MSE.
Note
The use of Context-Aware Services for wired device location is entirely optional. In the School SRA,
Context-Aware Services may be deployed for wireless devices, wired devices, or for both.
The district office, large school, and small school design of the Schools SRA provides that in the event
of a failure of a switch line card in a 4500 series context-aware Catalyst switch, or a stack member in the
3750 switch stack, NMSP sessions recover from the failure without intervention from the user. For the
Schools SRA design, NMSP session recovery time from isolated switch stack member or line card
failure was seen to occur in the lab very quickly, and in most cases the recovery time was almost
unnoticeable from the perspective of the Mobility Services Engine. Careful examination of the NMSP
session status during simulated failures indicated that sessions remained up, intact, and passing NMSP
data while stack member or line card hand-off occurred.
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While still a relatively new context-aware capability, the inclusion of wired device tracking provides new
visibility into the location of wired IP endpoints in your school network. For example, some of the ways
that this new exciting capability can be used in the Schools SRA design include:
•
Determining the whereabouts of missing IP phones, PCs, and peripheral devices such as printers and
network scanners that have disconnected and moved from their originally installed locations to other
locations within a school (or moved to another school). Once reconnected to the network, the MSE
would be updated with the wired device's new attachment information and any location and/or ELIN
information defined for that switch port.
•
Keeping track of the location of host computers located in the district data center or in any school.
The wired location capabilities contained in release 6.0 of Context-Aware Services make it possible
to specify the location of a device down to the room, cubicle, seat, or even rack/slot location (see
Figure 6-32). This can be important in verifying that equipment to be de-commissioned is actually
removed from service and sanitized of all student information.
Figure 6-32
•
Displaying the Location of a Wired Host
Determining the civic location of users based on their IP address or the user name that was specified
during 802.1x / EAP login (refer to Figure 6-33). Context-Aware Services for wired devices makes
it possible to quickly determine the civic or emergency line identifier information associated with
the switch port. Figure 6-33 illustrates how we can search for the wired device by the known
username.
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Figure 6-33
•
Searching for Wired Device by Username
For devices that support it, impromptu inventory checks of devices across the school district by
examining wired device listings by serial number (see Figure 6-34) and comparing this information
to deployment records. This can help school and district administrators better determine whether
assets have been moved between schools without authorization.
Figure 6-34
Examining Device Serial Numbers Via Wired Device Tracking
In contrast to the manner in which searches for wireless clients and tags is handled via the WCS Monitor
> Maps, in Release 6.0 of Context-Aware Services, all wired client searches are handled via the Services
> Mobility Services >Context Aware Services > Wired > Wired Clients menu panel. Searches using
the wired client WCS menu panel are specific to the particular MSE that you have selected.
Hardware and Software Requirements for Wired Device Tracking
As mentioned previously, at the current time wired device tracking is only performed on Catalyst switch
hardware such as the 2960G, 3560E, 3750E, 3750G, 4500, and 4900 series. The images used for testing
of wired device tracking during the production of this chapter included:
•
cat4500e-entservicesk9-mz.122-53.SG.bin
•
c3750-ipservicesk9-tar.122-50.SE3.tar
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Note
•
c3750e-universalk9-tar.122-50.SE3.tar
•
c2960-lanbasek9-tar.122-50.SE3.tar
Readers should note that cryptography-enabled (k9) switch images are required in order to enable wired
device tracking in Catalyst switches.
•
You should be aware that including wired device tracking in your design will require additional
tracked device licenses on the MSE over and above that required for wireless device tracking alone.
This is because wired tracked devices are included in the maximum number of simultaneous devices
that can are licensed for tracking by an MSE. For example, a school that would otherwise possess a
maximum licensed tracked device requirement of 500 for wireless LAN clients, RFID tags, and
rogues might require 750 or more when wired device tracking is considered, depending on the
number of switches deployed and whether wired device tracking is enabled for all of them. Be sure
to plan appropriately for the number of wired devices that you intend to track when purchasing MSE
client tracking licenses for the Cisco Context-Aware Engine for Clients.
In addition to planning appropriately for an increase in MSE tracked device licensing due to the use of
wired device tracking, keep in mind that although a single MSE can technically support up to 500 NMSP
sessions, scalability testing limits have only allowed Cisco to test up to 100 simulated NMSP
connections to a single MSE at this time. Each context-aware switch that is enabled for wired device
tracking in your network establishes one NMSP session to the MSE and counts against this limit.
Therefore, when enabling many switches for context-aware wired device tracking, it is recommended
that you plan for the total number of MSEs that may be required to support the total number of NMSP
sessions in your network.
Enabling Context-Aware Wired Device Tracking
In order to track wired devices on Catalyst switch ports, each switch whose devices we wish to track
must be configured to enable NMSP and other important parameters, and to contain the appropriate civic
address and ELIN location information. In addition, WCS must be configured to be aware of the
context-aware switches in the network and to be able to communicate with them. WCS is also used to
transmit information about the switches to the Mobility Services Engine via the synchronization process.
A complete, step by step guide to configuring Catalyst switches and WCS for wired device tracking can
be found in the Context Aware Service Configuration Guide 6.0
http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch7_CAS.h
tml#wp1224011.
In addition, the following chapters and documents provide valuable and detailed background
information concerning the wired device tracking capability of Catalyst switches:
•
Configuring LLDP, LLDP-MED, and Wired Location Service in the Catalyst 3750 Switch Software
Configuration Guide, 12.2(50)SE
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_50_se/configur
ation/guide/swlldp.html
•
Configuring LLDP, LLDP-MED, and Wired Location Service in the Catalyst 2960 Switch Software
Configuration Guide, 12.2(50)SE
http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_50_se/configur
ation/guide/swlldp.html
•
Configuring LLDP and LLDP-MED in the Catalyst 4500 Series Switch Software Configuration
Guide, 12.2(53)SG
http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/53SG/configuration/swlldp.html
#wp1097119
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Readers are reminded that:
•
NMSP is disabled on switches by default and must be explicitly enabled via the nmsp enable global
configuration command.
•
IP device tracking must be enabled on the switch in order for Context-Aware wired device tracking
to function properly. It can be enabled by issuing the ip device tracking in global configuration mode
on the context-aware switch.
•
The civic location identifier in the LLDP-MED TLV is limited to 250 bytes or less. To avoid
receiving error messages regarding available buffer space during switch configuration, the total
length of all civic location information specified for each civic-location identifier must not exceed
250 bytes.
•
In Release 6.0, all wired device client and switch tracking is available only to the root WCS virtual
domain user. Because of this, you may wish to limit the use of context-aware wired device tracking
to only those users with whom you are comfortable assigning WCS root virtual domain privileges.
NMSP Attachment Notification Interval
After an NMSP session is established between the MSE and a context-aware Catalyst switch, the MSE
transmits an Echo Response packet to the switch every echo interval period, which is specified on the
MSE (for all NMSP session partners) using the WCS menu entitled Services > Mobility Services >
System > NMSP Parameters. In addition to Echo Responses, the switch will periodically send
attachment notifications to the MSE via the NMSP session. Any link-up or link-down events that are
detected by the switch are aggregated during a configurable time interval and sent to the MSE via an
attachment notification at the conclusion of that time interval.
This interval is known as the nmsp attachment notification interval and is configurable on the switch via
the nmsp notification interval attachment interval-seconds command. The range of values for
interval-seconds is from 1 to 30 seconds, with 30 seconds being the default. In large networks where
there are many NMSP sessions active across the MAN to an MSE and the number of users connecting
and disconnecting from the switch is high, configuring nmsp attachment notification interval to a very
short interval can increase the amount of NMSP traffic between switches and the MSE and is not
recommended7 without carefully understanding the nature of the traffic present in your network.
Civic Address Configuration
The information contained in the Context Aware Service Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch7_CAS.
html#wp1224011) provides the information necessary to configure context-aware switches and the WCS
for wired device tracking.
As can be seen in the Context Aware Service Configuration Guide, in release 6.0 of Context-Aware
Services all configuration of civic and ELIN location information is performed on each context-aware
switch using the switch CLI. Once a switch is configured with the desired civic and ELIN location
information, the switch will share all of the configured port information with the MSE when the NMSP
session is initially established and will periodically update the MSE if any location updates are
performed.
Note
Readers should find the following IETF RFC documents helpful in better understanding the types of
values that should be specified for the various civic location fields: RFC 4776
(http://www.ietf.org/rfc/rfc4776.txt), RFC 4589 (http://www.ietf.org/rfc/rfc4589.txt), and RFC 5139
(http://www.ietf.org/rfc/rfc5139.txt).
7. Except for switches that are local to the Mobility Services Engine and need not traverse the MAN.
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During the course of our lab testing, we discovered other useful facets of information regarding civic
location and ELIN configuration in Catalyst switch IOS releases 12.2-52(SE) and 12.2-53(SG):
•
Global Scope of Civic and ELIN location—Civic address or ELIN information must be configured
at a global level and then assigned to each switch interface using the appropriate civic or ELIN
location identifier. Globally defined civic address parameters (such as the building, county, postal
code, floor, and so on) cannot be individually over-ridden at the interface level in release 6.0. If more
than one switch port shares the same civic location or ELIN, then the same globally specified civic
and ELIN location identifiers can be used on each switch port interface. However, if all ports possess
unique civic address characteristics, then uniquely specified global civic address parameters for
each port must be used. This can be seen in the following example where three unique civic location
identifiers are applied to three different ports (Gi1/0/3 - 1/0/5). The test application server that is
being tested on port Gi 1/0/6 is in the same physical location as the device connected to port Gi1/0/5,
hence they share civic-location identifier 3.
location civic-location identifier 1
additional-code “NCES District 611460 County 6037"
building “Hart Building”
city Downey
country US
county “Los Angeles”
floor “Floor 3"
name “Unified School District Office”
postal-code 90241
state California
street-group “Brookshire Avenue”
number 11627
room 300
seat 3H103
type-of-place “District Office”
!
location civic-location identifier 2
additional-code “NCES District 611460 County 6037"
building “Hart Building”
city Downey
country US
county “Los Angeles”
floor “Floor 3"
name “Unified School District Office”
postal-code 90241
state California
street-group “Brookshire Avenue”
number 11627
room 300
seat 3H104
type-of-place “District Office”
!
location civic-location identifier 3
additional-code “NCES District 611460 County 6037"
building “Hart Building”
city Downey
country US
county “Los Angeles”
floor “Floor 3"
name “Unified School District Office”
postal-code 90241
state California
street-group “Brookshire Avenue”
number 11627
room 300
seat 3H105
type-of-place “District Office”
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!
interface GigabitEthernet0/3
description 802.1x data access only
location civic-location-id 1
switchport access vlan 88
switchport mode access
authentication port-control auto
dot1x pae authenticator
!
interface GigabitEthernet0/4
description 802.1x data access only
location civic-location-id 2
switchport access vlan 88
switchport mode access
authentication port-control auto
dot1x pae authenticator
!
interface GigabitEthernet0/5
description 802.1x data access only
location civic-location-id 3
switchport access vlan 88
switchport mode access
authentication port-control auto
dot1x pae authenticator
!
interface GigabitEthernet0/6
description test school local RFID gate application server
location civic-location-id 3
switchport access vlan 56
switchport mode access
!
•
Civic location additional-location-information subcommand—During the course of our testing we
found the additional-location-information subcommand useful in adding miscellaneous
information about devices that can be displayed on the civic address tab of the WCS wired clients
display under “Address Line 2". In our testing, we made use of this facility to label the rack and
position location of various servers and other devices that are deployed in a common location.
Figure 6-35 illustrates how the information entered using additional-location-information is then
displayed on the civic address tab of the WCS wired clients display for the device (indicated by the
red arrow). Below the configuration for the switch port, we can see the results of displaying the civic
location for the switch interface using the location civic-location interface interface command.
Figure 6-35
Additional-Location-Information
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•
Civic Location street-group subcommand—In order to display a value under the street name
component on the civic address tab of the WCS wired clients display, we found it was necessary to
use the civic location street-group subcommand in the switch configuration. If we look again at the
left hand portion of Figure 6-35, we can see the street-group is specified as “Brookshire Avenue”.
On the right hand of Figure 6-35, we see that this value appears under the civic address tab of the
WCS wired clients display under the label “Street”.
Excluding Device Tracking on Select Switch Ports
In the majority of cases, when using context-aware wired device tracking, it is usually acceptable to
simply enable NMSP on the switch and allow the attachment status of all ports to be reported to the MSE.
In this way, the attachment status and any location or ELIN information specified for each port in the
switch is reported and can be accessed from the MSE. However, in some cases, it might be desirable to
enable wired device tracking on a switch, but exclude selected switch ports from reporting device
attachments to the MSE. A reason for doing this might be to help reduce the number of MSE tracked
device licenses required by eliminating the NMSP reporting of device attachments on select ports where
not much chance of device migration is expected. Recall that in release 6.0, while it is possible to enable
or disable wired device tracking entirely on a per MSE basis, it is not possible to limit the number of
wired devices that are tracked in each MSE at this time (i.e., wired device tracking is either on or off).
Therefore, any such limiting must be done manually by either disabling NMSP sessions with selected
switches entirely (no nmsp enable) or disabling only the tracking of select switch ports on a
context-aware switch that is otherwise reported device attachments normally.
To disable device tracking for select switch ports on a switch where NMSP has been enabled, the switch
interface configuration nmsp attachment suppress command should be specified on each switch
interface where device tracking is not desired. The nmsp attachment suppress interface command is used
to configure the interface to not send any attachment notifications to a Cisco Mobility Services Engine
(MSE).
If you are using Location MAC Filtering (Services > Mobility Services > Context Aware Service >
Administration> Filtering Parameters) to specifically limit or block (by MAC address) tracked
wireless clients and tags, be advised that these address filters also apply to wired device clients as well.
Make sure that any filtering specifications that you set using Location MAC Filtering are flexible enough
to allow tracking of not only your wireless clients and tags, but wired devices as well. Any devices that
have been blocked from location tracking as a result of a defined filter will be viewable under the
“Blocked MACs” listing on the Filtering Parameters page. Detailed information regarding how to
configure Location MAC filtering can be found in Modifying Filtering Parameters section of the Cisco
Context-Aware Service Configuration Guide 6.0
(http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/msecg_ch7_CAS.
html#wp1100062).
Classification and Marking of NMSP Sessions
A vital component in assuring NMSP session stability and acceptable CAS performance during periods
of network congestion is the application of QoS to NMSP data flows between the MSE and any WLAN
controllers or context-aware Ethernet switches in the Schools SRA design. Classification, marking and
QoS should be applied ideally in both cases of locally deployed as well as centralized MSE
implementations, however, it is especially important when using a centralized MSE at the district site
and remote WLAN controllers and context-aware Ethernet switches in the schools.
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In order to ensure that QoS prioritization can occur properly for NMSP sessions the NMSP data flows
must be properly identified, classified and marked as close as possible to their points of origin. This
section explains where such marking of NMSP data flows should occur in the network, and how it should
be performed.
Figure 6-36 provides an example of where identification, classification and marking of NMSP data
flows should occur in the case of the school district design containing:
•
A district office with adjoining data center
•
A school site that is based on the Catalyst 4500 for distribution
•
A school site that is based on the Catalyst 3750 switch stack for distribution.
In Figure 6-36, we have identified several points where classification and remarking needs to occur in
order to properly mark NMSP traffic inbound from WLAN controllers and context aware switches, and
outbound from Mobility Services Engines. These points are indicated by the yellow and red numbered
circles.
Figure 6-36
Points of NMSP Classification and Marking
Optional Backup
WLAN Controller(s)
Wireless
Control System
2
WLAN
Controller
2
District
Office
Access
Control
System
1
3
Services Block
4
MSE
Mobility Services
Engine
3
Cisco 2960G
Cisco 3750G
IP
IP
Metropolitan
Area
Network
Access
Control
System
1
2
School Site
Cisco 4500
Distribution
WLAN
Controller
Access
Control
System
3
4
3
2
MSE
Mobility Services
Engine
WLAN
Controller
4
3
Cisco 2960G
3
Cisco 3560G
IP
Cisco 3750G
IP
IP
227895
IP
Cisco 2960G
School Site
Cisco 3750 Stack
Distribution
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NMSP Traffic Flows Originating At The MSE
NMSP sessions between the MSE, WLAN controllers and context-aware switches are bi-directional in
nature. Here, we are referring simply to that portion of any flow whose source address is that belonging
to the Mobility Services Engine. Since the Mobility Services Engine does not mark the DSCP for the
NMSP traffic it transmits into the network, all such traffic originating at the MSE will contain the default
DSCP marking of 0x00. Left unchanged, when congestion is encountered in the Schools SRA design all
NMSP traffic marked in this fashion will be treated with the lowest priority. This increases the
probability that NMSP session data will be dropped in the network during periods of congestion. Left
unchecked, this can result in NMSP session stability issues, and poor context-aware performance.
Clearly, this is not desirable. We can avoid this by classifying and remarking NMSP data appropriately,
as described in this section.
Since the MSE currently does not support classification and marking the DSCP value assigned to its
traffic, we must make use of the classification and marking capabilities available to us in the Ethernet
switch to which the MSE is attached. Thus, where 1 appears in Figure 6-36, we will:
•
Define the criteria to select our NMSP traffic
•
Define a class-map that will filter NMSP traffic using this criteria
•
Define a service-policy to assign our desired DSCP value to the filtered traffic using the class-map
•
Apply the service-policy to the port to which the MSE is attached.
Since we know that NMSP traffic will involve TCP port 16113, we can make use of this to identify
NMSP traffic and proceed to mark it appropriately.
The following example defines a policy map that will mark NMSP traffic inbound to the network from
the MSE as DSCP 0x12 (also referred to as DSCP 18, Assured Forwarding 21), police down to 10 Mbps
per 8k burst, and mark down any NMSP traffic exceeding this accordingly using the QoS map.
mls qos
!
class-map match-all CAS
match access-group name NMSP
!
policy-map MSE-Policy
class CAS
set dscp af21
police 10000000 8000 exceed-action policed-dscp-transmit
!
ip access-list extended NMSP
remark Identify NMSP traffic
permit tcp any any eq 16113
permit tcp any eq 16113 any
On the switch interface where the MSE is attached, it is imperative that service-policy statement appears
to assign the policy map to the interface. For example:
interface GigabitEthernet1/0/2
description Mobility Services Engine MSE1
.
.
service-policy input MSE-Policy
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NMSP Traffic Generated By WLAN Controllers
As was the case with the MSE, NMSP traffic entering the network originating at the WLC is also marked
with the default DSCP value of 0x00. Left unchanged, when congestion is encountered in the Schools
SRA design all NMSP traffic marked in this fashion will be treated with the lowest priority. Once again,
this is not desirable and we shall address it in this section.
Like the MSE, the WLAN controller does not provide us with the ability to mark the NMSP traffic as
we see fit, thus we must instead classify and mark this traffic inside the network. In accordance with
general best practices, this operation is performed as close in the network as possible to the WLAN
controller. Therefore, in Figure 6-36, the points at which this should occur are shown by 2. Note that
traffic coming from both normally active as well as any backup WLAN controllers located in the data
center services switch block must be classified and marked.
The method used to accomplish this classification and marking for WLAN controllers is very similar to
that presented in the previous section for the MSE. However, since the WLAN controller is attached to
the Ethernet switch using an Etherchannel port-channel group, there will be some relevant differences
relating to whether the port-channel attachment is to a Catalyst 3750 switch stack or Catalyst 4500
distribution switch.
For example, when using the Catalyst 3750 switch stack in distribution, the following configuration
would apply:
mls qos
!
class-map match-all CAS
match access-group name NMSP
!
policy-map CAS-Policy
class CAS
set dscp af21
police 10000000 8000 exceed-action policed-dscp-transmit
!
ip access-list extended NMSP
remark Identify NMSP traffic
permit tcp any any eq 16113
permit tcp any eq 16113 any
The 3750 switch stack would also have a port-channel definition that would refer to the two physical
Ethernet interfaces comprising the port-channel group.
interface Port-channel4
description EC trunk to school 1266, WLC, interfaces gig1/0/28, 2/0/28
It is important to note that the 3750 switch stack does not support the use of a policy-map statement on
a port-channel definition. In order to assure that NMSP traffic originating at the WLAN Controller
in-bound to the network is properly classified and marked, ensure that a service-policy statement appears
on each of the two physical interfaces that comprise the WLAN controller port-channel group in the
3750 switch stack. For example:
interface GigabitEthernet1/0/28
description trunk to school 1266 WLC, port-channel4
.
.
mls qos trust dscp
channel-group 4 mode on
service-policy input CAS-Policy
!
interface GigabitEthernet2/0/28
description trunk to school 1266 WLC, port-channel4
.
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.
mls qos trust dscp
channel-group 4 mode on
service-policy input CAS-Policy
When using the Catalyst 4500 as the distribution switch, the scenario is a bit different. The Catalyst 4500
requires the service-policy to be assigned to the port-channel group used for the WLAN controller, and
not the physical interfaces. Thus, our recommended configuration when using a Catalyst 4500 in
distribution would be as follows:
!
class-map match-all CAS
match access-group name NMSP
!
policy-map CAS-Policy
class CAS
set dscp af21
police cir 10000000
conform-action transmit
exceed-action set-dscp-transmit default
!
ip access-list extended NMSP
remark Identify NMSP traffic
permit tcp any any eq 16113
permit tcp any eq 16113 any
!
interface Port-channel6
description trunk to district WLC, interfaces gig2/11, gig3/11
.
.
service-policy input CAS-Policy
!
!
interface GigabitEthernet2/11
description trunk to district WLC, port-channel6
.
.
channel-group 6 mode on
!
interface GigabitEthernet3/11
description trunk to district WLC, port-channel6
.
.
channel-group 6 mode on
!
NMSP Traffic Generated By Context-Aware Switches
As you will recall, specific models of Catalyst switches described earlier in this document (such as the
2960G, 3560, 3750, 4500, 4900 and others) can provide context-aware information to the MSE relating
to IP-based attached devices. When this capability is enabled in a context-aware switch, the switch itself
participates in an NMSP session with the MSE. This NMSP session is separate and independent of any
NMSP sessions that may pass through the switch to or from attached devices (such as the WLAN
controllers described earlier, or other downstream context-aware switches).
In order to ensure that the NMSP traffic originating at these switches is treated appropriately in the
network during times of congestion, it is important that we properly classify the NMSP data originating
at the context-aware switch and destined in-bound to the network for the MSE. Depending on the type
of switch used, the exact method we shall use to apply this classification and marking will vary.
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Layer-Three Context-Aware Switches
In the case of context-aware Layer-3 switches such as the 3750, 3560 and 4500, we can make use of local
policy routing to assign an IP precedence 2 (DSCP 0x10) to NMSP traffic originating from the switch
itself. Local policy routing in this fashion is performed internal to the context-aware L3 switch
originating the NMSP traffic, and the traffic is marked prior to being introduced into the network. At the
locations in Figure 6-36 marked with 3, we can perform the required classification using a local policy
route-map as follows:
ip local policy route-map switch-NMSP
!
route-map switch-NMSP permit 10
match ip address NMSP
set ip precedence 2
set ip tos max-throughput
!
ip access-list extended NMSP
permit tcp any any eq 16113
permit tcp any eq 16113 any
!
Layer Two Context-Aware Switches
However, the use of the Cisco 2960G context-aware layer two (L2) switch in the access layer presents a
challenge. Local policy routing is not supported by the L2-only 2960G. Therefore, as a workaround, we
must classify and mark the NMSP traffic originating from the 2960G at the next switch upstream to it in
the network. In the Schools SRA design, this upstream switch would be the 3750 switch stack or 4500
distribution switch. In Figure 6-36, the points at where this must be performed are indicated by 4.
Note that in the Schools SRA design, the 2960G access layer switches are attached to the distribution
switches using an Etherchannel port-group, in a fashion very similar to that of the WLAN controllers.
Therefore, similar techniques can be used to classify and mark the NMSP traffic originating at the 2960G
and coming across the Etherchannel link.
Thus, for a 3750 switch stack used in distribution, a class-map and policy-map can be applied as
described previously, and the service-policy input CAS-Policy statement applied to the physical
interfaces in the 3750 switch stack that comprise the port-channel group to the 2960G switch. Just as for
an Etherchannel-attached WLAN controller, a service-policy cannot be applied to the port-channel
group definition used for the 2960G.
When using a Catalyst 4500 as the distribution switch with a context-aware 2960G at the access layer,
apply the service-policy input CAS-Policy statement to the port-channel group definition for the
2960G. This would be done in a similar fashion to that described earlier for a Etherchannel-attached
WLAN controller.
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Hardware/Software Releases
Hardware/Software Releases
Table 6-2
Hardware/Software Releases
Component
Version
Comments
Wireless Control System
6.0.132.0
For licensing and part number information, see
http://www.cisco.com/en/US/prod/collateral/wireless/ps5755/ps630
1/ps6305/product_data_sheet0900aecd804b4646.html
Mobility Services Engine 3350
6.0.85.0
For client and tag licensing information, see
http://www.cisco.com/en/US/prod/collateral/wireless/ps9733/ps974
2/data_sheet_c07-473865.html
Mobility Services Engine 3310
6.0.85.0
For client and tag licensing information, see
http://www.cisco.com/en/US/prod/collateral/wireless/ps9733/ps974
2/data_sheet_c07-473865.html
WLAN Controller 4404
6.0.182.0
Standalone Cisco Wireless LAN Controller
WLAN Controller 4402
6.0.182.0
Standalone Cisco Wireless LAN Controller
Catalyst 4500
12.2.53-SG
Large school distribution switch; must use crypto (K9) image if CAS
for wired devices is desired
Catalyst 3750E Switch Stack
12.2(52)SE
Small school distribution switch; must use crypto (K9) image if CAS
for wired devices is desired
Catalyst 2960G
12.2(52)SE
Access switch; must use crypto (K9) image if CAS for wired devices
is desired
Catalyst 3750E
12.2(52)SE
Access switch; must use crypto (K9) image if CAS for wired devices
is desired
LAP1252 Access Point
6.0.182.0
Cisco Aironet 1250 Series Wireless Access Point
LAP1142 Access Point
6.0.182.0
Cisco Aironet 1140 Series Wireless Access Point
WCS Navigator
1.5.132.0
Optional component; for licensing information, see
http://www.cisco.com/en/US/prod/collateral/wireless/ps5755/ps630
1/ps7305/product_data_sheet0900aecd8065bd19.html
AeroScout T2 RFID Asset Tag
4.33
Available from http://www.aeroscout.com/; RFID tags are required
only if RFID tracking is desired
AeroScout T3 RFID Asset Tag
6.05
Available from http://www.aeroscout.com/; RFID tags are required
only if RFID tracking is desired
AeroScout EX-3200 Exciter
33007/60007
Chokepoint trigger, optional RFID enhancement; EX-2000 model
recommended if outdoor placement is necessary
Context-Aware Services—General Best Practice References
The following are recommended references with regard to general best practice deployment
recommendations for Cisco Unified Networks making use of Context-Aware Services release 6.0:
•
A cornerstone of a successful design is knowledge of established best practices. Thus, it is highly
recommended that you become familiar with the material presented in the following documents:
– Context-Aware Solution Deployment Guide
http://www.cisco.com/en/US/products/ps9742/products_tech_note09186a00809d1529.shtml
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– VoWLAN Design Guide 4.1
http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/vowlan/41dg/vowlan41dg-bo
ok.html
– Context-Aware Services Configuration Guide, Release 6.0
http://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide/CAS_60.h
tml
– Wireless LAN Controller Configuration Guide, Release 6.0
http://www.cisco.com/en/US/docs/wireless/controller/6.0/configuration/guide/Controller60C
G.html
– Wireless Control System Configuration Guide, Release 6.0
http://www.cisco.com/en/US/docs/wireless/wcs/6.0/configuration/guide/WCS60cg.html
•
If you intend to make use of RFID tags in your Context-Aware solution, it is also recommended that
you become familiar with the following document which explains the operation of the Cisco
Context-Aware Engine for Tags:
– AeroScout Context-Aware Engine for Tags for Cisco MSE User Guide, version 3.2
http://support.aeroscout.com
•
If you intend to track the location and status of wired devices attached to Catalyst Ethernet switches,
it is recommended that you familiarize yourself with the appropriate configuration guide for this
feature in the switches you will be using. For example:
– Catalyst 2960 Switch Software Configuration Guide, 12.2(50)SE
http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_50_se/con
figuration/guide/scg.html
– Catalyst 3750 Switch Software Configuration Guide, 12.2(50)SE
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_50_se/con
figuration/guide/scg.html
– Catalyst 4500 Series Switch Software Configuration Guide, 12.2(53)SG
http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/53SG/configuration/config.
html
During any deployment of Context-Aware Services and Cisco Unified Wireless Networks, detailed site
surveys should be performed by a Cisco Wireless LAN Specialized Partner with expertise in voice, high
speed data, and Context-Aware wireless network deployment. Cisco Systems also offers a complete
package of bundled design and deployment services via the Cisco Advanced Services team. Cisco and
our Wireless LAN Specialized Partners offer Context-Aware Design and Implementation Services to
help you successfully deploy enterprise-class wireless connectivity. These services include the
installation and configuration of crucial components such as the Mobility Services Engine (MSE),
helping you to take full advantage of the strong security, management, and investment protection
features that are built into Cisco Context-Aware components. In addition to planning, design, and
implementation, we also offer services based on proven methodologies for operating and optimizing the
performance of a Context-Aware Mobility solution, along with its associated technologies and strategies.
Note
The importance of a properly performed wireless site survey of your facility cannot be over-emphasized.
For more information on Cisco bundled planning, design, and deployment services, refer to
http://www.cisco.com/en/US/services/ps2961/ps6899/ps8306/services_overview_context_aware.pdf.
To locate a Cisco Wireless LAN Specialized Partner, refer to
http://tools.cisco.com/WWChannels/LOCATR/openAdvanceSearch.do.
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7
Unified Communications Design
Introduction
While many school networks still use legacy PBX phone systems, many are migrating to the advantages
of IP-based voice. Lower in cost, and more flexible and reliable, the Cisco Unified Communications
suite of solutions provides great benefits to a school network. Based on years of best practice
recommendations, this chapter provides information on the advanced suite of communications,
collaboration, and mobility features in the Cisco Unified Communications solution set.
This chapter provides guidance for deploying Cisco Unified Communications. It covers the dial-plan
principles recommended for a school district, along with recommended solutions for ensuring
communications survivability during a WAN outage, and emergency 911 call capabilities.
School Service Ready Architecture Dial Plan
The CUCM dial plan discussed here is appropriate for deployments supporting up to 100 schools. This
dial plan is for a centralized CUCM cluster in the school District Office supporting up to 100 schools
over a 100Mbps Metro Ethernet WAN.
Note
This document is based on the UC SRND version 7 that can be accessed at the following URL:
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/uc7_0.html. The dial plan chapter of
the UC SRND is the authoritative source for dial plan guidance and should be referenced for more details
and more options than are provided in the example deployment provided in this chapter.
Design Assumptions
The following design aspects and requirements are assumed:
•
Connectivity between schools and district office is via hub-and-spoke Metro Ethernet WAN.
•
Metro Ethernet provides sufficient bandwidth and low enough latency to support centralization of
CUCM at the district office for all sites in the network.
•
The network is configured with the appropriate QoS policy to support a voice deployment.
•
CUCM provides centralized call control for all sites in the network.
•
Call processing redundancy at the district office is provided by a CUCM cluster.
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School Service Ready Architecture Dial Plan
•
Access to the PSTN is provided by PSTN gateway functionality running on a Cisco Integrated
Services Router (ISR) router at each school and in the district office.
•
At the school sites, additional call processing redundancy is provided by SRST in the Cisco ISR at
that site. If phones at a remote sites lose connectivity with the CUCM over the WAN link, they can
fall back to SRST mode whereby they register with the SRST function in the Cisco ISR router local
to that site
•
Same site calling; every phone can call any other internal phone at the same site using four-digit
extension.
•
Inter-site calling; calls between phones in different sites of the same school district use 8 as an
access code, followed by a site code, followed by the four-digit extension.
•
PSTN gateways at the district office and remote sites provide PSTN connectivity.
Example Deployment
Dial-plan testing was performed on an example network of three sites in a deployment designed to scale
up to 100 sites. The example deployment is shown in Figure 7-1.
Figure 7-1
Sample Dial-Plan
District Office
Cisco
7970G
IP
Cisco
7971G
IP
Cisco
7906G
IP
8333-1001 8333-1001 8333-1001
X1001
X1002
X1003
M
M
M
M
M
333-456-1xxx
L2/L3
IP Network
PSTN
222-345-1xxx
444-567-1xxx
IP
Cisco
7971G
IP
Cisco
7906G
IP
Cisco
7970G
IP
Cisco
7971G
IP
Cisco
7906G
IP
8444-1001 8444-1001 8444-1001
X1001
X1002
X1003
8222-1001 8222-1001 8222-1001
X1001
X1002
X1003
School 1
School 2
227482
Cisco
7970G
In the example deployment, each of the sites has less than 8,000 phones and can therefore use a 4-digit
internal extension. The following Direct Inward Dial DID blocks are assumed to have been issued by
the local telecoms operator:
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•
District office DID block 333-456-1000 through 333-456-1799
•
School 1 DID block 444-567-1000 through 444-567-1799
•
School 2 DID block 222-345-1000 through 222-345-1799
Within each of the three sites, dialing will be by four-digit extension (x1000 through x1799)
Between sites, dialing will use 8 as an access code, followed by a site-code (in the example, this is area
code assigned to that sites PSTN gateway), followed by the four-digit extension.
•
District office phones dialed from school 1 or school 2 will be dialed as 8-333-1000 through
8-333-1799.
•
School 1 phones dialed from district office of school 2 will be dialed as 8-444-1000 through
8-444-1799.
•
School 2 phones dialed from district office of school 1 will be dialed as 8-222-1000 through
8-222-1799.
Note
In the example above, each site has a unique area code that is mapped directly to a site code. In a typical
deployment, the expectation is to see multiple schools using the same area code; this requires site codes
to be assigned by other means.
Note
You must ensure that the on-net access code and site code combination do not overlap with the local
abbreviated dialing range at any site. This is accomplished by ensuring that no abbreviated dial extension
start with the digit 8.
Variable-Length On-Net Dial Plans with Flat Addressing
This document discusses a dial plan that is appropriate for deployments where the CUCM cluster in the
school district office supports up to 100 schools over a 100Mbps Metro Ethernet WAN.
There are two main approaches to a dial plan for internal destinations within an IP Telephony system:
•
Uniform on-net dial plan—All extensions in a uniform on-net dial plan are reached in a uniform
way. Every internal call destination has a unique number of defined length. Uniform on-net dial
plans are the easiest to design and configure; however, they become impractical when the number
of sites and users increases due to the following reasons:
– All on-net extension dialing must be globally unique. For example, in a system using an
abbreviated 4-digit on-net dial plan, there cannot be an extension 1000 in site A and another
extension 1000 in site B. This requirement is very difficult to satisfy in large deployments where
the extension is derived from the DID blocks obtained from local telecoms companies.
– There cannot be any partial overlap between different dial strings. For example, if 9 is used as
an off-net access code in a 4-digit abbreviated dial plan (for example, to make PSTN calls),
there cannot be any extensions in the 9XXX range. Attempting to do so would create situations
where calls are not routed immediately. For example, if a user dialed 9141, the system would
have to wait for either more digits (if the user were dialing 9 1 415 555 1234, for example) or
the expiration of the inter-digit timeout before routing the call to extension 9141. Likewise, if
an operator code is used (for example, 0), the entire 0XXX extension range would have to be
excluded from a four-digit uniform dial plan.
– There cannot be overlapping strings of different length. For example, a system with extensions
1000 and 10000 would force users to wait for the inter-digit timeout when they dial 1000.
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•
Variable-length on-net dial plan—This is where internal destinations are dialed differently within a
site than across sites. Typically, this approach uses four or five-digit abbreviated dialing for calls
within a site and an on-net access code followed by a site code and the extension for calls across
sites.
– Variable-length on-net dial plans are more scalable and better allow for future expansion or
changes to the dial plan. For this reason, variable-length on-net dial plans are used in this design
guide.
– A variable-length on-net dial plan with flat addressing is implemented by defining internal call
destinations as unique strings containing an on-net access code, a site code, and the extension
(for example, 8-123-1000). Flat addressing places all the directory numbers in the same global
partition, thus enabling inter-site calls using the site code. Translation patterns are defined in
site-specific partitions (one translation pattern and one partition per site) to enable abbreviated
dialing within a site.
•
Alternative to using site codes—The UC7.x SRND discusses a variant of the flat addressing
approach that does not rely on the definition of an on-net numbering plan based on site codes. In
this scheme, internal call destinations are defined with their full E.164 number. Intra-site calls use
translations patterns to ensure they can still dialed as four-digit numbers. Inter-site calls are dialed
using the E.164 number and are then recognized and routed across the IP WAN by Unified CM.This
option was not used in this document because the site code approach results in numbers that are
shorter and easier to remember; for example, the dial plan could be set up so that every school
principal has a non-DID second extension of 7000. With this scheme in place, it is possible to dial
the principal at any school by dialing 8, the site code, and 7000. The site code approach is also
preferred because many schools do not have E.164 DID numbers assigned to each phone; instead
they route calls through an IVR or an operator.
Call Routing
The dial plan in this document is designed with the following structure:
•
Localized Call Ingress—Accept calls in the local format preferred by the originating users and
carriers. Convert called and calling numbers to a globalized format.
•
Globalized Call routing—Route the calls on-net using global representations of the called and
calling numbers.
•
Localized Call Egress—Deliver the calls to phones or gateways and convert the called and calling
numbers from the globalized format to the local format required by the destination user or network.
The benefits of the dial-plan design approach are most compelling when deploying UC across diverse
countries and telephony carriers, but as a Cisco UC best practice, the new design approach still has
benefits to a smaller network such as that which would be used by a school district. Some of those
benefits include the following:
•
Dial plan is consistent with Cisco best practice recommendations and scales globally
•
Simplified configuration of call routing, especially when considering local egress to the PSTN
•
Simplified configuration and enhanced functionality of system functions such as:
– Automated Alternate Routing (AAR)
– Emergency Responder (ER) site-specific failover
– Call Forward Unregistered (CFUR)
– Tail End Hop Off (TEHO)
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– Click-to-dial of E.164 numbers (including the + sign) from soft clients such as Cisco Unified
Personal Communicator
– Adaptive call routing for speed dials originating from roaming extension mobility users or
roaming devices
– One-touch dialing from phone directory entries, including dual-mode phones
– One-touch dialing from missed and received call lists in IP phone directories
Note
The dial plan in this document uses several features introduced in CUCM 7.0.
Localized Call Ingress
Localized call ingress is where the UC system accept calls in the local format preferred by the
originating users and carriers and then converts called and calling numbers into 8-digit local phone
numbers for CUCM on-cluster numbers, and to the full E.164 format for PSTN numbers.
Using the + Sign on E.164 Numbers
When an external called or calling number is converted to the globalized representation on input, a +
sign is used to represent the international dialing access code needed to reach a destination from different
countries.
For calls that egress via a PSTN gateway, localized call egress will replace the + in a called number with
the appropriate off-net access code (as required by the enterprise telephony system) and international
access code (as required by the PSTN carrier) relevant for each caller.
Even though the Telephony User Interface (TUI) does not allow for dialing + from the keypad, the
missed and received calls directories can contain entries where the number includes a +. On 7911, 7941,
7942, 7945, 7961, 7962, 7965, 7970, 7971, and 7975 phones, if the user dials from those directories, the
resulting call into Unified CM will have a called number beginning with +. (7905, 7912, 7940, and 7960
phones do not support storing or displaying the + sign).
This section discusses the following:
•
Localized call ingress on IP phones
– Localized called number on IP phones
•
IP phones called number is a 4-digit local extension
•
IP phones called number is on the external PSTN
– Localized calling number on IP phones
•
Localized call ingress on gateways
– Localized called number on gateways
– Localized calling number on gateways
Localized Call Ingress on IP Phones
This section discusses localized call ingress on IP phones and Soft phones.
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Localized Called Number on IP Phones
If a user dials the full 8-digit directory number of an on-cluster phone line, the called number does not
need to be manipulated, and is routed directly. This section will discuss the cases where the called
number is one of the following:
•
A 4-digit local extension
•
A full E.164 PSTN number
IP Phones Called Number is a 4-digit Local Extension
For on-net destinations, such as calls between two users in the same site, translation patterns are used to
derive the globalized on-net form of the destination number. For example, assume two users in the Site
1 use 4-digit abbreviated dialing to call each other. User A calls user B by dialing 1234. A translation
pattern specific to this site is configured to recognize any 4-digit string beginning with 1 and to translate
the called number to the globalized on-net form of 84441234. The translation pattern is configured as:
1XXX, prefix 8444.
The translation pattern must be site-specific (included in the CSS of only the phones in Site 1) to avoid
confusion with extension 1234 at other sites in the system. In the example above, the on-net global form
is implemented using an inter-site access code (8) and a site code (444). After the call has been translated
into a 8-digit global on-net number, the CSS of the translation pattern is used to direct the call to the
destination partition and route pattern.
Figure 7-2 shows an example configuration for intra-site calls within the CUCM cluster used in the
sample network.
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Localized Call Ingress for On-net Calls
CSSs
pt-on-cluster
83331000
83331001
…
84441000
84441001
…
82221000
82221001
…
IP
District Office
Site code: 333
Extensions 1xxxx
IP
Site 1
Site code: 444
Extensions 1xxxx
css-do-devices
pt-do-loc-trans
1xxx [Prefix 8333]
css-s1-devices
pt-s1-loc-trans
1xxx [Prefix 8444]
css-s2-devices
pt-s2-loc-trans
1xxx [Prefix 8222]
Directory Numbers
Partitions
Translation Patterns
Figure 7-2
Returns 83331xxx
Returns 84441xxx
IP
Returns 82221xxx
227483
Site 2
Site code: 222
Extensions 1xxxx
To provide connectivity between sites and partitions, the sample network used the following guidelines:
•
Place all unique DNs, including the on-net access code 8, in a global partition (named Internal_pt
in this example).
•
Create one partition per site, each containing a translation pattern that expands four-digit numbers
into the fully qualified eight-digit number for that site, thus enabling abbreviated dialing within the
site.
•
For each site, include both the Internal_pt partition and the local translation partition in the phone's
calling search space. The inclusion of the on-net access code in the DN configured in Unified CM
enables you to place all internal extensions in a partition directly accessible by all phones, and at
the same time ensures that all call directories on the IP phones are populated with numbers that can
be directly redialed.
IP Phones Called Number is on the External PSTN
For calls to numbers on the PSTN, translation patterns should be used to derive the globalized on form
of the destination number.
•
Add the local area code to any 7-digit PSTN numbers.
•
Replace the PSTN access code (for example, 9) and any international dialing access code (eg 011),
with a + sign.
With these changes to the called number, the call could be routed or re-routed to any gateway globally,
and the gateway would be able to route the call successfully.
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Figure 7-3
Localized Call Input; IP Phone Calling Off-net Dstination
M
CUCM Gateway definition
for District Office
Site code: 333
333-456-1xxx -> 83331xxx
CUCM Gateway definition
for Site 1
Site code: 444
444-567-1xxx -> 84441xxx
227485
CUCM Gateway definition
for Site 2
Site code: 222
222-345-1xxx -> 82221xxx
Figure 7-3 shows the following partitions:
•
NANP_Loc2glob—The system has one translation pattern, used by all sites, to perform the
following modifications to called numbers:
– Remove the PSTN access code of 9 on emergency numbers
– Replace the PSTN access code of 9 with the + code, on National numbers
– Replace the PSTN access code and the international dialing access code with the + code on
international calls.
•
xx_loc2glob—Each site has a site-specific partition containing a translation pattern to replace the
PSTN access code for 7 digit local dialing with the + code and the NNAP country code of 1, and the
local area code for that site.
•
NNAP_pstn_part—The translation patterns in the other partitions translated numbers into a
globalized number. After the call has been translated into a E.162 off-net number, the CSS of the
translation pattern is used to direct the call to the NNAP_pstn_part partition. The NNAP_pstn_part
partition is used by all sites, to route globalized called numbers out the appropriate gateway. The
Globalized call routing section will detail how the gateways are used for each of the patterns in this
partition.
– There are patterns for each sites local area code so that Tail End Hop Off may be used to route
the call to the gateway local to that area code.
– The +1xxxxxxxxxx pattern is for NNAP numbers
– The +! pattern will route international calls.
– Emergency numbers (911) should always be routed out the local gateway of the calling phone,
when available.
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Localized Calling Number on IP Phones
On cluster IP phones are configured with a directory number that is in the global on-net format. In this
example the directory number is an 8-digit number that includes the access code, the site number, and
the 4-digit extension. This directory number is already in the globalized format and is therefore not
changed on ingress. If the call is directed out a gateway, the calling number will be changed by the
gateway to a full E.164 number.
Localized Call Ingress on Gateways
Just as with IP phones discussed previously, we need to localize call ingress on gateways. We accept
incoming calls on gateways in the local format of the telephone network to which the gateway is
connected, and we convert the called and calling numbers to a globalized format. The global format is
later used to route the call within the voice over IP network to its destination.
Localized Called Number on Gateways
Incoming PSTN calls require that the E.164 number be manipulated to obtain the eight-digit internal
number in order to reach the destination phone. Within this example dial-plan, this requirement has been
implemented by configuring the Num Digits and Prefix Digits fields within the Gateway Configuration
page in Unified CM. These fields strip and then prefix the needed digits.
In Figure 7-4, the Significant Digits field maps the last 4 digits of the incoming called DID number to
the local 4-digit extension. The Prefix DN field adds the inter-site access code (8) and a site code (222).
Figure 7-4
Converting from localized PSTN called DID number format to globalized on-net
directory number format
M
CUCM Gateway definition
for District Office
Site code: 333
333-456-1xxx -> 83331xxx
CUCM Gateway definition
for Site 1
Site code: 444
444-567-1xxx -> 84441xxx
227485
CUCM Gateway definition
for Site 2
Site code: 222
222-345-1xxx -> 82221xxx
Localized Calling Number on Gateways
Incoming calling party settings can be configured on individual gateways, at the device pool level, or at
the service parameter level, in order of precedence. For each numbering type (Subscriber, National,
International, or Unknown), Unified CM allows for the appropriate prefix digits to be configured. Digits
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can be stripped from and prefixed to the string provided as the incoming party number. The notation
takes the form PP:SS, where PP represents the digits to be prefixed and SS represents a quantity of digits
to be stripped. The digit stripping operation is performed first on the incoming calling party number, and
then the prefix digits are added to the resulting string. For example, if the prefix digits field is configured
as +33:1 and the incoming calling party number is 01 58 40 58 58, the resulting string will be +33 1 58
40 58 58.
Figure 7-5 shows the incoming calling-party settings for the gateway at school 2.
Figure 7-5
Localized calling party number on gateways
M
CUCM Device Pool definition
for District Office
Site code: 333
CUCM Device Pool definition
for Site 1
Site code: 444
227486
CUCM Gateway definition
for Site 2
Site code: 222
For the example dial plan above, the following actions are taken:
•
Incoming national calls have the area code included in the calling number, and the gateway is
configured to add the + and the 1 for North America.
•
Incoming international calls have the international country code included in the calling number, and
the gateway is configured to just add the +.
•
For incoming unknown calls, the gateway is configured to just add the +.
•
For incoming subscriber calls, and the gateway is configured to add the + and then the 1 for North
America, and then the local area code for that gateway.
Globalized Call Routing
In this section, we assume the calling number has been manipulated into one of the following:
•
Globalized to an 8-digit on-net number
•
Globalized to an E.164 external number
This section discusses how the call is routed to the appropriate destination.
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Globalized Call Routing to an 8-digit On-net Number
The sample network is deployed as a single CUCM cluster the CUCM cluster has full knowledge of
every 8-digit on-net number, and can route calls directly to the destination phone.
Globalized Call Routing to an E.164 External Number
Where the destination is an external PSTN number, we have to route the call to the appropriate PSTN
gateway. Figure 7-6 shows how calls are routed in our example deployment. Route patterns point to
route lists that in turn point to egress gateways.
Figure 7-6
Call Routing Example
Partitions
Route Lists
Route Groups
rl-s1-teho
S1-RG
LRG
DO-RG
S1-RG
rl-s2-teho
S2-RG
LGR
DO-RG
V
V
S1 Gateways (444)
S2-RG
Local
Route
Group
V
V
S2 Gateways (222)
DO-RG
rl-nnap
LRG
DO-RG
S1-RG
V
V
DO Gateways (333)
227487
pt-nnap-pstn
+1444!
+1222!
+1333!
+1XXXXXXXXXX
+!
911
rl-do-teho
DO-RG
LRG
S1-RG
The following discussion of the dial plan in Figure 7-6 includes the use of local route groups which are
discussed further in the section following this one.
The route patterns that include the area code implement Tail End Hop Off (TEHO) by pointing to a route
list which is comprised of the following route groups:
•
A route group containing the gateways at the local site in which the directly connected gateways are
connected.
•
A route group containing the local route group which will route calls out a gateway connected to the
site the calling phone is dialing from. For more details on local route group, refer to “Using Local
Route Group” section on page 7-12.
•
A route group containing the gateways at a different site. This provides redundancy in the event that
the previous two route groups both point to the gateways at the same site.
The route patterns in Figure 7-6 for national, international, and emergency calls point to a route list that
is comprised of the following route groups:
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•
A route group containing the Local Route Group which will route calls out a gateway connected to
the site the calling phone is dialing from. For more details on Local Route Group, refer to “Using
Local Route Group” section on page 7-12.
•
A route group containing the gateways at the district office.
•
A route group containing the gateways at Site 1. This provides redundancy in the event that the
previous two route groups both point to the gateways at the same site.
Other variations are possible in a real deployment. For example, it might be preferable to route some
calls out the district office as a first choice, and out the Local route group if the district office gateways
are unavailable.
Using Local Route Group
Local Route Group is a Cisco Unified CM 7.0 feature that simplifies the configuration of site-specific
routing of off-net calls. Route patterns using the local route group allow for dynamic selection of the
egress gateway, based on the device originating the call.
Before local route group route patterns were site specific. For example, before local route groups:
•
The 911 route pattern for site 1 would point to site 1's PSTN gateway
•
The 911 route pattern for site 2 would point to site 2's PSTN gateway.
With local route groups, a single 911 route pattern can be configured pointing to the Local Route
Group.
•
Phones in sites 1 and 2 will use the PSTN gateway pointed to by the Local Route Group field in each
sites device pool.
•
Phones acquire their local route group from the Local Route Group field in the phones’ device pool.
Localized Call Egress
Calls are routed to a destination using the global form of the called and the calling numbers. These
numbers need to be transformed into the format expected by the telephone network to which the gateway
is connected.
Localized Call Egress to an IP Phone
Called Number
In this dial plan, IP phones directory numbers are the same as the globalized on-net number format; no
conversion of the called number is required.
Calling Number
As a call is delivered to a phone, the calling number will be in its global form, which might not be
recognizable to the called party. Typically, users prefer to see calls from callers within their country
presented with an abbreviated form of the caller's number.
For example, users in the US want to see incoming calls from US callers with a ten-digit national
number, without the + sign or the country code (1). If a user whose global phone number is +1 222 345
1234 calls +1 333 456 4000, the called phone would like to receive 222 345 1234 as the calling-party
number while the phone is ringing.
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To achieve this, the system administrator should configure a calling-party transformation pattern of:
+1.!, strip pre-dot. The calling-party transformation pattern is placed in a partition included in the
destination phone's calling-party transformation pattern CSS, configured at the device-pool level. As a
call from +1 222 345 1234 is offered to the phone, it matches the configured calling-party transformation
pattern, which removes the +1 and presents a calling-party number of 222 345 1234 as the call rings.
Figure 7-7 shows how the device pool of the destination phone determines the calling party
transformation
Figure 7-7
IP Phone Outgoing Calling-Party Transformation
CUCM
CSSs
Partitions
M
CUCM Device Pool
for District Office
“Calling Party Transformation
CSS” field
Site code: 333
pt-do-calling-party-trans
css-do-calling-party-trans
pt-s1-calling-party-trans
css-s1-calling-party-trans
css-s2-calling-party-trans
CUCM Device Pool
for Site 2
“Calling Party Transformation
CSS” field
Site code: 444
\+.1xxxxxxxxxx, pre-dot, national
pt-s2-calling-party-trans
\+.1xxxxxxxxxx, pre-dot, national
227488
CUCM Device Pool
for Site 1
“Calling Party Transformation
CSS” field
Site code: 222
Translation Patterns
\+1.xxxxxxxxxx, pre-dot, national
Note
The calling-party number stored in the missed and received calls directories is left in its globalized form
to allow one-touch dialing from the directories without requiring manual editing of the directory's stored
number string.
Note
Many phone users are becoming accustomed to the globalized form of PSTN numbers, mainly due to the
common use of mobile phones across international boundaries. The system administrator can forgo the
configuration of calling-party transformation patterns for phones if displaying the global form of
incoming numbers is preferred.
Localized Call Egress to a Gateway
Gateway Called-Party Number Localization
As a call is delivered to a gateway, the called party number must be adapted to the requirements of the
PSTN service provider providing the trunk group to which the gateway is connected. Called-party
number transformation patterns can be used to change the called-party number digit-string and
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numbering type. Typically, a called-party number featuring the gateway's country code should be
changed to remove the + sign and the explicit country code, and they should be replaced with the national
prefix. Also, the numbering type of the called-party number should be changed to national. If the
gateway is connected to a trunk group featuring a specific area, region, or city code, the specific
combination of + sign, country code, and local area code usually must be replaced by the applicable local
prefix. Also, the numbering type must be adjusted to subscriber.
For example, assume that a call to an external user in site 1s area code (+1 444 555 2222) is routed
through a route list featuring a Site 1 gateway (San Francisco) as a first choice and a Site 2 (Chicago)
gateway as a second choice. The Site 1 gateway is configured with two called-party transformation
patterns:
•
+1444.XXXXXXX, strip pre-dot, numbering type: subscriber
•
+1.!, strip pre-dot, numbering type: national
As the call is delivered to the Site 1 gateway, the called-party number matches both of the called-party
transformation patterns. However, the first one is a more precise match and is selected to process the
called party number. Thus, the resulting transformed number is 5552222, with a called party type set to
subscriber.
If the gateway had not been able to process the call (for example, if all ports were busy), the call would
have been sent to the Site 2 gateway to egress to the PSTN. The Chicago gateway is configured with the
following two called-party transformation patterns:
•
+1222.XXXXXXX, strip pre-dot, numbering type: subscriber
•
+1.!, strip pre-dot, numbering type: national
As the call is delivered into the Chicago gateway, the called-party number matches only the second
called-party transformation pattern. Therefore, the resulting called-party number offered to the gateway
is 4445552222, with a called-party number type set to national.
Figure 7-8 shows how the device pool of the destination gateways determines the calling-party
transformation.
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Figure 7-8
Gateway Called-Party Transformation
CUCM
CSSs
Partitions
M
CUCM Device Pool
for District Office
“Called Party Transformation
CSS” field
Site code: 333
css-do-called-party-trans
CUCM Device Pool
for Site 1
“Called Party Transformation
CSS” field
Site code: 222
pt-s1-called-party-trans
\+1222.xxxxxxx, pre-dot, subscriber
\+.1xxxxxxxxxx, pre-dot, national
\+.!, pre-dot, international
css-s1-called-party-trans
css-s2-called-party-trans
pt-s2-called-party-trans
\+1444.xxxxxxx, pre-dot, subscriber
\+.1xxxxxxxxxx, pre-dot, national
\+.!, pre-dot, international
227489
CUCM Device Pool
for Site 2
“Called Party Transformation
CSS” field
Site code: 444
Translation Patterns
pt-do-called-party-trans
\+1333.xxxxxxx, pre-dot, subscriber
\+.1xxxxxxxxxx, pre-dot, national
\+.!, pre-dot, international
Gateway Calling Party Number Localization
As a call is delivered to a gateway, the calling-party number must be adapted to the requirements of the
PSTN service provider providing the trunk group that the gateway is connected to. The calling-party
number transformation patterns can be used to change the calling-party number digit-string and
numbering type. Typically, a calling-party number featuring the gateway's country code should be
changed to remove the + sign and the explicit country code, and they should be replaced with the national
prefix. Also, the numbering type of the calling-party number should be changed to national. If the
gateway is connected to a trunk group featuring a specific area, region, or city code, the specific
combination of + sign, country code, and local area code usually must be replaced by the applicable local
prefix. Also, the numbering type must be adjusted to subscriber.
For example, assume that a call from a Site 1 user (+1 444 567 1234) is routed through a route list
featuring a San Francisco gateway as a first choice and a Chicago gateway as a second choice. The San
Francisco gateway is configured with two calling-party transformation patterns:
•
+1444.XXXXXXX, strip pre-dot, numbering type: subscriber
•
+1.!, strip pre-dot, numbering type: national
As the call is delivered to the Site 1 gateway, the calling-party number matches both calling-party
transformation patterns. However, the first one is a more precise match and is selected to process the
calling-party number. Thus, the resulting transformed number is 5671234, with a calling-party type set
to subscriber.
If the gateway had not been able to process the call (for example, if all ports were busy), the call would
have been sent to the Site 2 gateway to egress to the PSTN. The Site 2 gateway is configured with the
following two calling-party transformation patterns:
•
+1222.XXXXXXX, strip pre-dot, numbering type: subscriber
•
+1.!, strip pre-dot, numbering type: national
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Building Classes of Service for Unified CM with the Line/Device Approach
As the call is delivered into the Chicago gateway, the calling-party number matches only the second
calling-party transformation pattern. Therefore, the resulting calling-party number offered to the
gateway is 4445671234, with a calling-party number type set to national.
Figure 7-9 shows how the device pool of the destination gateways determines the calling-party
transformation pattern.
Figure 7-9
Gateway Calling-Party Transformation Pattern
CUCM
CSSs
Partitions
M
CUCM Device Pool
for District Office
“Calling Party Transformation
CSS” field
Site code: 333
css-s1-calling-party-trans
css-s2-calling-party-trans
CUCM Device Pool
for Site 2
“Calling Party Transformation
CSS” field
Site code: 444
pt-s1-calling-party-trans
\+1222.xxxxxxx, pre-dot, subscriber
\+.1xxxxxxxxxx, pre-dot, national
pt-s2-calling-party-trans
\+1444.xxxxxxx, pre-dot, subscriber
\+.1xxxxxxxxxx, pre-dot, national
227490
css-do-calling-party-trans
CUCM Device Pool
for Site 1
“Calling Party Transformation
CSS” field
Site code: 222
Translation Patterns
pt-do-calling-party-trans
\+1333.xxxxxxx, pre-dot, subscriber
\+1.xxxxxxxxxx, pre-dot, national
Building Classes of Service for Unified CM with the Line/Device
Approach
Class-of-Service (CoS) for the Cisco Unified CM refers to the ability to apply call restrictions to certain
users and/or phones in the dial plan. The dial plan outlined above allows every IP phone to dial any
destination; local, long distance, or international. When it is necessary to dial restrictions to certain
phones, this document uses the line/device approach.
The line/device approach works by appending the line CSS to the device CSS on each phone. If the same
route pattern appears in two partitions, one contained in the line's calling search space and one contained
in the device's calling search space, then the Cisco Unified CM selects the route pattern listed first in the
concatenated list of partitions (in this case, the route pattern associated with the line's calling search
space).
In the route plan listed above, every phone had a device CSS that allowed it to call any destination. CoS
will be applied by defining a line CSS for the restricted lines, that will override the device CSS and deny
access to defined call destinations.
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Survivable Remote Site Telephony (SRST)
To better understand how to apply these rules, consider the example shown in Figure 7-10, where the
device calling search space contains a partition with route patterns to all PSTN numbers, including
international numbers. The route patterns point to a PSTN gateway via the route list and route group
construct.
Figure 7-10
Line/Device Approach
Line CSS
selectively blocks
undesired routes
(according to
class of service)
15644
15644
15644
Your current options
Redail NewCall CFwdAll
Line CSS
Block Int'l Partition
9.011!
more
Line
“Blocked” Route Pattern
Resulting CSS
Block Int'l Partition
9.011!
PSTN Partition
IP
Device
9.1 [2-9]XX [2-9]XX XXXX
...
9.011!
“Routed” Route Patterns
9.011!
227491
Device CSS
allows access to?
all external routes
Device CSS
PSTN Partition
9.[2-9]XXXXXX
At the same time, the line calling search space contains a partition with a single translation pattern that
matches international numbers and that has been configured as a blocked pattern. The resulting calling
search space therefore contains two identical patterns matching international numbers, with the blocked
pattern in the line calling search space appearing first. The result is that international calls from this line
will be blocked.
Survivable Remote Site Telephony (SRST)
When deploying the Cisco Unified Communications across a WAN with the centralized call processing
model, additional steps must be taken to ensure that data and voice services at the remote sites are highly
available.
The Schools SRA design uses SRST to provide high availability for voice services, by providing a subset
of the call processing capabilities within the remote office router and enhancing the IP phones with the
ability to “rehome” to the call processing functions in the local router if a WAN failure is detected.
Figure 7-11 illustrates a typical call scenario with SRST.
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Survivable Remote Site Telephony (SRST)
Figure 7-11
Survivable Remote Site Telephony (SRST)
Central site
Central site
IP
IP
IP
IP
IP
IP
Unified CM
cluster
Unified CM
cluster
M
M
M
M
V
V
ISDN
backup
V
V
ISDN
backup
PSTN
M
PSTN
IP WAN
IP WAN
Voice traffic
Voice traffic
V
V
Signaling
Signaling
IP
IP
IP
Branch office
IP
Branch office
Normal operation
WAN failure
74353
M
Under normal operations shown in the left part of Figure 7-11, the branch office connects to the central
site via an IP WAN, which carries data traffic, voice traffic, and call signaling. The IP phones at the
branch office exchange call signaling information with the Cisco Unified CM cluster at the central site
and place their calls across the IP WAN. The branch router or gateway forwards both types of traffic
(call signaling and voice) transparently and has no knowledge of the IP phones.
If the WAN link to the branch office fails, or if some other event causes loss of connectivity to the Cisco
Unified CM cluster, the branch IP phones reregister with the branch router in SRST mode. The branch
router SRST queries the IP phones for their configuration and uses this information to build its own
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Survivable Remote Site Telephony (SRST)
configuration automatically. The branch IP phones can then make and receive calls either internally or
through the PSTN. The phone displays the message “Unified CM fallback mode,” and some advanced
Unified CM features are unavailable and are grayed out on the phone display.
When WAN connectivity to the central site is reestablished, the branch IP phones automatically
reregister with the Unified CM cluster and resume normal operation. The branch SRST router deletes its
information about the IP phones and reverts to its standard routing or gateway configuration. Unified
CME running in SRST mode at the branch can choose to save the learned phone and line configuration
to the running configuration on the Unified CME router by using the auto-provision option. If
auto-provision none is configured, none of the auto-provisioned phone or line configuration information
is written to the running configuration of the Unified CME router. Therefore, no configuration change
is required on Unified CME if the IP phone is replaced and the MAC address changes.
Note
When WAN connectivity to the central site is reestablished, or when Unified CM is reachable again,
phones in SRST mode with active calls will not immediately re-register to Unified CM until those active
calls are terminated.
SRST CUCM Configuration
When communication with the CUCM is lost, the default SRST action is for IP phones to attempt to register
to the router listed as their default gateway. In the example deployment used in this guide, the IP phones
default gateway is not the ISR router running SRST, so a SRST instance needs to be configured on CUCM
to tell the IP phones what router to register with instead when communication with CUCM is lost. The SRST
reference is configured to point to the ISR router. This is configured by navigating to System -> SRST on
CUCM. See Figure 7-12.
Figure 7-12
Configuring SRST Reference
After the SRST instance is defined, it needs to be added to the appropriate device pool corresponding to each
each site. This is configured by navigating to System -> Device Pool on CUCM.
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Survivable Remote Site Telephony (SRST)
When a remote phone is in SRST mode, and is unregistered to the CUCM but still reachable from the
PSTN,CUCM to be configured to know how to reach it. The required configuration is shown in Figure 7-13.
Figure 7-13
Configuring Call Forward Unreachable in CUCM for Remote Phones in SRST Mode
In Figure 7-13, The Forward Unregistered Internal setting is set to forward to the PSTN number of
814445671001 when this phone line is unregistered to CUCM. This setting also has a specific CSS in order
to override any restrictions that might otherwise prevent callers from using the PSTN.
SRST Router Configuration
The sections of Site2 ISR router configuration that are relevant to the SRST configuration are provided
below.
ccm-manager fallback-mgcp
! — This command causes the gateway to fall back and provide call processing services if
connectivity is lost between the gateway and all Cisco CallManager servers.
application
global
service alternate default
! — If the MGCP application is not available, the default application (H.323) takes over.
call-manager-fallback
!--- Enables SRST support and enters Cisco CallManager fallback mode.
max-conferences 12 gain -6
transfer-system full-consult
ip source-address 10.40.63.9 port 2000
! — The IP address used by SRST must match the IP phones default gateway, or if an SRST
reference is configured the phones device pool in CUCM, it must match that.
max-ephones 10
max-dn 20
!
!
dial-peer voice 1 pots
description srst incoming
translation-profile incoming S2-SRST-in
service mgcpapp
incoming called-number .
direct-inward-dial
port 2/0/1:23
forward-digits 8
dial-peer voice 91 pots
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description SRST; Any long distance number
destination-pattern 91..........
port 2/0/1:23
forward-digits 10
dial-peer voice 91444 pots
description SRST; PSTN School2 to School1
destination-pattern 91444.......
port 2/0/1:23
forward-digits 10
dial-peer voice 91333 pots
description SRST; PSTN School2 to district office
destination-pattern 91333.......
port 2/0/1:23
forward-digits 10
dial-peer voice 91222 pots
description SRST; School2 local dialing with area code
destination-pattern 91222.......
port 2/0/1:23
forward-digits 10
dial-peer voice 9345 pots
description SRST; School2 local dialing (PSTN-router num-exp adds area code)
destination-pattern 9345....
port 2/0/1:23
forward-digits 7
dial-peer voice 911 pots
description SRST; Emergency call without External access code
destination-pattern 911
port 2/0/1:23
forward-digits 3
dial-peer voice 84441 pots
description SRST; translate calls to School1 using internal number format
translation-profile outgoing S2-SRST-out
destination-pattern 84441...
port 2/0/1:23
forward-digits 10
dial-peer voice 83331 pots
description SRST; translate calls to District office using internal number f
translation-profile outgoing S2-SRST-out
destination-pattern 83331...
port 2/0/1:23
forward-digits 10
dial-peer voice 9911 pots
description SRST; Emergency call with External access code
destination-pattern 9911
port 2/0/1:23
forward-digits 3
!
!
voice translation-rule 1
rule 1 /^222345/ /8222/
voice translation-rule 10
rule 1 /^84441/ /4445671/
rule 2 /^83331/ /3334561/
voice translation-profile S2-SRST-in
translate called 1
! — Called by Dial-peer 1 to translate incoming calls from E.164 format to local CUCM
phone number format
voice translation-profile S2-SRST-out
translate called 10
! — Called by Dial-peers 8333 and 8444 to translate outgoing calls to phones at another
CUCM site from local CUCM phone number format to E.164 format.
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Emergency Notification of 911 Calls with Cisco Emergency Responder
Emergency Notification of 911 Calls with Cisco Emergency
Responder
Ease of administration for adds, moves, and changes is one of the key advantages of IP telephony
technology. To provide for adds, moves, and changes that automatically update 911 information without
user intervention, Cisco has developed a product called the Cisco Emergency Responder (Cisco ER).
The Schools SRA design uses Cisco ER to provide the following primary functionality:
Note
•
Dynamic association of a phone to an ERL, based on the detected physical location of the phone.
•
Dynamic association of the emergency location identification number (ELIN) to the calling phone,
for callback purposes. Cisco ER enables the callback to ring the exact phone that initiated the 911
call.
•
On-site notification to designated parties (by pager, web page, or phone call) to inform them that
there is an emergency call in progress. The pager and web page notifications include the
calling-party name and number, the emergency response location (ERL), and the date and time
details associated with the call. Phone notification provides the information about the calling
number from which the emergency call was placed.
For more information on Cisco ER, refer to the Unified Communications SRND and to the Cisco ER
product documentation available online at the following URL:
http://www.cisco.com/en/US/products/sw/voicesw/ps842/tsd_products_support_series_home.html
The key functionality of Cisco ER relies on the detection of the phone's location by discovery of the
network port (Layer-2 port, such as a Fast Ethernet switched port) from which the phone made the 911
call. The discovery mechanism relies on two main assumptions:
•
The wired infrastructure of the enterprise is well established and does not change sporadically.
•
The infrastructure is available for Cisco ER to browse; that is, Cisco ER can establish Simple
Network Management Protocol (SNMP) sessions to the underlying network infrastructure and can
scan the network ports for the discovery of connected phones.
Once the Cisco ER discovers the originating port for the call, it associates the call with the preestablished
ERL for the location of that port. This process also yields an association with a preestablished ELIN for
the location and the selection of the appropriate egress point to the E911 infrastructure, based on the
originating ERL.
The School SRA dial plan is configured so that the system easily recognizes emergency calls, whether
an access code (for example, 9) is used or not; the system has been configured to recognize both the
strings 911 and 9911. The emergency route patterns have also been explicitly marked with urgent
priority so that Unified CM does not wait for the inter-digit timeout (Timer T.302) before routing the
call.
Voice Messaging
The Cisco Unified Communications messaging portfolio consists of three main messaging products:
Cisco Unity, Cisco Unity Connection, and Cisco Unity Express. Each product fits different
requirements, yet each one contains overlapping features and scalability with regard to the others. They
also have the ability to interwork with one another using Voice Mail Networking and can also leverage
the Cisco Unified Messaging gateway to achieve this in a highly scalable fashion, as discussed later in
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Voice Messaging
this chapter. When considering these products, it helps to think of the messaging types that the products
apply to in order to understand the messaging options they include and to determine which options could
fit your deployment requirements. The following definitions help define these messaging types:
•
Voicemail-only—Refers to a telephony voicemail integration where there is no access to the
voicemail via any messaging client.
•
Integrated messaging—Refers to voicemail with telephony access as well as voicemail-only access
via a messaging client.
•
Unified messaging—Refers to voicemail with telephony access as well as voicemail, E-mail, and
fax access via a messaging client.
Based on the above messaging types and definitions, the three messaging product options are as follows:
•
Cisco Unity—This solution option scales to meet the needs of large enterprise organizations and
delivers powerful voice, integrated, and unified messaging options that integrate with Microsoft
Exchange (including Exchange 2007) and Lotus Domino.
•
Cisco Unity Connection—This option combines integrated messaging, voice recognition, and call
transfer rules into an easy-to-manage system for medium-sized businesses with up to 10,000 users,
or it can network up to 5 systems to support larger-sized businesses with up to 50,000 users. For
organizations with up to 500 users, Cisco Unity Connection is available as a single-server solution
with Cisco Unified Communications Manager Business Edition.
•
Cisco Unity Express—This option provides cost-effective voice and integrated messaging,
automated attendant, and interactive voice response (IVR) capabilities in certain Cisco Integrated
Services Routers for small and medium-sized businesses and enterprise branch offices with up to
250 users.
For the Schools SRA test network, Cisco Unity 7.0 for Microsoft Exchange was deployed. Deploying
Unity allows for a centralized deployment with the greatest scalability and broadest feature set. The
following Unity collaboration capabilities are important in this decision;
Note
•
Unified messaging—Cisco Unity unified messaging integrates transparently with Microsoft
Exchange, allowing you to handle all your messages - E-mail, voice, and fax - through a single inbox
using the Outlook E-mail client. Icons provide simple visual descriptions of each message type, and
because every message is delivered to one inbox, you can see the number, type, and status of all your
communications at a single glance. You also can reply to, forward, and save your messages regardless of media type - in public or personal Microsoft Outlook folders with just a click of the
mouse, decreasing response times and increasing organizational agility and customer service.
•
Mobile access to voice messages—Cisco Unity unified messaging delivers all-in-one messaging for
mobile users. Mobile workers using a Palm Treo or RIM BlackBerry device can simply double-click
to play voice messages within their smartphone E-mail applications. The Cisco Unity solution
supports a variety of notification options that allow you to customize the way you are notified of
new voice messages. Cisco Unity Unified Messaging for Microsoft Exchange users can access their
voice messages using Cisco Unified Mobile Communicator, which integrates with Exchange to
provide mobile access to messages. Even for users with basic mobile phones, the Cisco Unity
solution is optimized to enhance mobile productivity. When you call in from a mobile phone, speech
recognition allows for hands-free usage of the system. If a call is dropped because of a
less-than-fully reliable mobile phone network, the Interrupted Session Recovery feature resumes,
on the next call-in, the session where the call left off, reducing lost time.
Unity requires integration with Microsoft Active Directory and Exchange, smaller school districts might
opt for a simpler Cisco Unity Connections deployment instead of deploying Unity.
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Cisco Unified Personal Communicator 7.0
Cisco Unified Personal Communicator 7.0
Cisco Unified Personal Communicator provides a very versatile communications platform to the schools
SRA. Cisco Unified Personal Communicator is a Microsoft Windows or Apple Mac application that
operates in one of two modes, Desk Phone (CTI control of the user's desk phone for click to call) and
Soft Phone (software client operation), and it is supported on Apple Macintosh and Microsoft Windows
platforms.
Cisco Unified Personal Communicator integrates the most frequently used communications applications
and services into a single desktop software application. Cisco Unified Personal Communicator
facilitates streamlined communications from your desktop or laptop computer, including integrated
contact lists, click to call, instant messaging, voicemail playback, inbound call notification, and media
escalation. By being able to control your communications from a single window, you can communicate
more effectively and be more productive.
Figure 7-14
Cisco Unified Personal Communicator
Cisco Unified Personal Communicator Features and Benefits
•
Communication integration—Take advantage of a single, intuitive interface for voice and video
calls, instant messaging, voicemail playback, web conferencing, and integrated directories.
•
Presence—View real-time availability of other Cisco Unified Personal Communicator and Cisco
Unified IP Phone users. You can also display customized messages, set an out-of-office message,
and automatically show your availability based on free and busy status on your Microsoft Outlook
Calendar.
•
Do not disturb (DND)—Easily block incoming calls with synchronized DND status from your Cisco
Unified Personal Communicator or Cisco Unified IP Phone or use the privacy preference setting to
block instant messages when you need additional privacy.
•
Contact list—Search your corporate directory from one easy-to-use interface to locate contacts
quickly and simply click to call. Add your most frequently contacted personal contacts, co-workers,
and federated business contacts
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Cisco Unified Mobility
•
Media escalation—Add communication methods during a conversation; for example, you can add
video to an audio conversation or add web conferencing or white-boarding to an existing audio or
video conversation.
•
Click to call—Dial from the contact list, using either the integrated softphone or an associated Cisco
Unified IP Phone. You can also click to call directly from Microsoft Outlook using an Outlook
toolbar.
•
Integrated voice and video calling—Exchange ideas face-to-face with a coordinated video display
on the PC screen and audio conversation with the softphone. You can place video calls using Cisco
Unified Personal Communicator, Cisco Unified Video Advantage, or the Cisco Unified IP Phone
7985G, a personal desktop videophone.
•
IP phone association—Use Cisco Unified Personal Communicator to control your desktop Cisco
Unified IP Phone to make, receive, or merge calls.
•
Instant messaging—Chat in real time using instant messaging with other Cisco Unified Personal
Communicator users to save time and reduce phone tag. In addition, enable business-to-business
federation between Cisco Unified Presence and Microsoft Live Communications or Microsoft
Office Communications server to exchange presence information and instant messages with
Microsoft Office Communicator and Cisco Unified Personal Communicator users.
•
Conferencing—Create voice or video conferencing sessions by simply merging conversation
sessions. There is no need to call into a separate conference bridge.
•
Web conferencing—Launch a Cisco Unified MeetingPlace, Cisco Unified MeetingPlace Express, or
Cisco WebEx web conferencing session at a moment's notice to share content, such as a
presentation, with others.
•
Voice messages—Access secure Cisco Unity® or Cisco Unity Connection encrypted voicemail
messages - view, play back, sort, and delete messages - all from within the application.
•
Languages supported for both Microsoft Windows and Apple Macintosh desktops include—Arabic,
Chinese (Traditional Chinese and Simplified Chinese), Danish, Dutch, English, French, German,
Italian, Japanese, Korean, Portuguese (Brazilian), Spanish, Russian, and Swedish.
Cisco Unified Mobility
Cisco Unified Mobility is natively available with Cisco Unified CM on the school SRA network. Cisco
Unified Mobility extends rich call control capabilities of Cisco Unified Communications Manager from
a mobile worker's primary workplace desk phone to any location or device of their choosing.
Some of the key benefits of enabling Cisco Unified Mobility capabilities with Cisco Unified
Communications Manager include:
•
Single Business Number Reach and Single Business Voicemail—Cisco Unified Mobility makes it
possible for workers to consolidate all their incoming business calls (i.e. incoming business calls to
mobile phones, home office phone, or any temporary telework phone) into a single business phone
number and immediately receive them wherever they are working. Coworkers, business partners,
and customers now only need a single business phone number to reach workers who can be more
responsive without additional effort. If mobile workers are unable to answer the call extended to one
of the many user-defined alternative phone numbers, they can rely on Cisco Unified Mobility to
store the unanswered calls into a single business voicemail on Cisco Unity ® or other business
voicemail system. Cisco Unified Mobility reduces the burden on workers of having to share multiple
phone numbers with business contacts and having to check multiple voicemail boxes at the end of
the day.
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Cisco Unified Mobile Communicator
•
Seamless Transition of Ongoing Extended Communications—Mobile phones are great when moving
from location to location, but when a mobile worker arrives at the office, they would rather take
advantage of speakerphone or other IP Phone services on their Cisco Unified IP Phone at their desk.
Cisco Unified Mobility provides seamless transition of extended ongoing calls from mobile phones
to desk phone and vice versa. This provides workers with the ability to maintain business
communications continuity while taking advantage of least cost routing of mobile calls across
company's IP communications infrastructure while in the office. Hence they can start the
conversation from their mobile phone and seamlessly transition that conversation to a desk phone
upon arrival in the office without needing to call back. Similarly they can transition the call
seamlessly back to the mobile phone and wander away at will for another appointment.
•
Cisco Mobile Voice Access—With Cisco Unified Mobility, workers who need to place national or
international calls from their mobile phone can use the Cisco Mobile Voice Access line to place the
call as if they are placing the call from their business extension on their desk. The worker dials the
Cisco Mobile Voice Access line from the mobile phone and places the call on the IP
communications network over a tie line. The call is connected and remains in control of Cisco
Unified Communications Manager providing the opportunity to reduce mobile communications
costs associated with national or international calls placed directly from mobile phone. With Cisco
Mobile Voice Access, the person being called sees the caller-id as coming from a desk phone in the
office rather than from the personal cell phone that may have actually initiated the call.
•
Access to Mid Call Control Cisco Unified Communications Manager Capabilities—Cisco Unified
Mobility extends key call control features of Cisco Unified Communications Manager (such as hold,
resume, transfer, and conferencing) on calls extended to devices and locations of the workers
choice. For workers who have become accustomed to such productivity capabilities in the office can
now access them while they are away from their desk.
•
Personalized Access Lists—Mobile workers can access the secure user profile webpage to enter
mobile and other alternate phone numbers and create filters that restrict the types of calls that are
extended using Cisco Unified Mobility. Cisco Unified Mobility intelligently manages, filters, and
routes each call between a worker's business extension and alternate phone numbers based on rules
defined by the worker on their profile. Unanswered calls are consolidated into single business
voicemail and voice communications resources are only used to extend relevant calls as determined
by rules specified by the worker.
•
Web-Based System Administration—Cisco Unified Mobility provides system administrators with
the flexible to define and manage user profiles. System administrators can use the secure
Administration Webpage to determine how much control users will have over their profiles and
make user profile changes when needed. Users enjoy the advantages of personal choice, while the
system administrator retains control over resource use and can provide backup support.
Cisco Unified Mobile Communicator
Cisco Unified Mobile Communicator (see Figure 7-15) is an easy-to-use software application for mobile
handsets that facilitates more effective communications for mobile employees. By extending enterprise
communications applications and services to mobile phones and smartphones, Cisco Unified Mobile
Communicator streamlines the communication experience, facilitating real-time collaboration across the
enterprise. With Cisco Unified Mobile Communicator, you can place and receive calls, access company
directory contacts, check presence information, and review voicemail messages, as well as receive Cisco
Unified MeetingPlace® notifications and other vital information-all from a single, intuitive interface
connected to Cisco Unified Communications.
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Cisco Unified Mobile Communicator
Figure 7-15
Cisco Unified Mobile Communicator
Using Cisco Unified Mobile Communicator, employees have the Key Features and Benefits available
on the mobile cellular phone;
•
Communication integration—Use one intuitive interface for mobile calls, directory and presence
information, voicemail playback, text messaging, and conferencing.
•
Unified contact list—Search your corporate directory (Active Directory) and personal contacts
(Microsoft Outlook) from one easy-to-use interface to locate contacts quickly. Simply select a name
to call.
•
Presence—Find a contact and see whether the person is available to talk-before placing the call.
View a person's availability status from the directory on the mobile handset.
•
Select to call—Dial from the directory by simply selecting a name.
•
Single-business-number reach—Provide colleagues with a single number to reach you. Supported
by Cisco Unified Mobility, calls to your desk phone can be answered from your mobile phone. If
you are busy, simply decline or ignore the call and it will be diverted to your office voicemail.
•
Secure text messaging—Send and receive text messages from colleagues when they are unavailable
to talk. A visual list on your mobile handset shows at a glance who is trying to reach you. Incoming
messages are conveniently grouped by person, showing the sender, the priority, and a brief subject
line, if available.
•
Voice messages—Access Cisco Unity® voicemail messages to select, view, play back, and delete
messages in any order, all from the mobile handset.
•
Conferencing—Receive notifications of conference calls on your mobile phone from the Cisco
Unified MeetingPlace solution. Simply press a button to call the conference bridge.
•
Call logs—View a list of recent calls on your mobile phone and learn what calls were missed,
placed, and received from your mobile phone or your Cisco Unified IP Phone.
•
Security—Cisco Unified Mobile Communicator is deployed securely behind the enterprise firewall.
Cisco Unified Mobile Communicator uses industry-standard, Secure Sockets Layer (SSL) and
Transport Layer Security (TLS) encryption to protect transmission of data between handsets and
your data center. End users authenticate with existing Lightweight Directory Access Protocol
(LDAP) directories. If a mobile handset is lost or stolen, IT staff can remotely deactivate the device
and erase sensitive company information.
•
Management—Simple, Web-based management allows IT staff to manage user activation,
configuration, and administration; set system privileges and security; report statistics; and manage
devices. The end-user portal allows provisioning, directory management, and configuration of user
preferences.
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Cisco Unified Mobile Communicator
•
Broad operator and device support—Working simultaneously across multiple networks, mobile
operators, and handset platforms, Cisco Unified Mobile Communicator helps ensure end-user
choice and delivery of consistent performance at work, at home, and on the road.
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Digital Media and Video Surveillance Design
Digital Media System Overview
The schools Service Ready Architecture (SRA) network architecture in combination with the Cisco
Digital Media System (DMS) creates an environment which streamlines and automates information flow
and process throughout school districts.
The evolution of digital communication in the 21st century education environment is transforming
processes and empowering educators to develop and deploy “eye-catching”, compelling, and integrated
video content.
•
Digital media communication in school systems is an extremely effective tool to deliver dynamic
and cost effective subject matter to staff and students.
•
Using digital media school systems keeps the education community connected, increases awareness,
and integrates with safety and security system notifications.
•
Integrating digital media technologies assists teacher's curriculum development and professional
development.
•
Comprehensive digital video systems transform video delivery processes in individual classrooms;
school administrator can create customized, on-demand educational video content or even relay live
video feed during national events or local emergencies.
Video Surveillance Overview
Video surveillance has been a key component of safety and security groups for many organizations. As
an application, video surveillance has demonstrated its value and benefits countless times by providing
real-time monitoring of a facility’s environment, people, and assets as well as by recording events for
subsequent investigation, proof of compliance, and audit.
For school systems that need to visually monitor or record events video, surveillance has become more
important as the number of security risks increases. In addition to video analytics, the value of video
surveillance has grown significantly with the introduction of motion, heat, and environmental sensors.
In a typical school environment, several systems are deployed for disparate applications, such as
physical access control, fire and smoke detection, and video surveillance. These applications typically
do not communicate with each other and require different management and support personnel. As a
result, owners and operators suffer from a lack of operational consistency, interoperability, and
capabilities that translate into higher capital and operational costs and limit the return on their
investment.
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Cisco’s solution offers software and hardware to support video transmission, monitoring, recording, and
management. Cisco video surveillance solutions work in unison with the advanced features and
functions of the IP network infrastructure—switches, routers, and other network security devices—to
enable secure, policy-based access to live and recorded video.
Cisco Digital Media System Architecture
Cisco has developed a comprehensive, scalable, and network-centric DMS architecture that is built on
three major digital application components. Each application is specifically designed to address key
challenges, regardless of how or where the digital content is designed and developed. The multifunction
management and adaptive media system is common to these three applications:
•
Desktop video—Interactive education training application that allow students to watch instructional
videos on-demand or via live streaming. Students can use classroom PCs to navigate a Cisco Video
Portal database to securely access relevant training video content.
•
Enterprise TV—While the targeted users for desktop video applications are individuals or group of
students, enterprise TV expands the same video capability to a larger audience and so extends the
classroom. Live or on-demand pre-recorded training video can be broadcast in a classroom. In
addition to internally developed video material, district and school administration can also enable
live educational TV programming like science, discovery, etc.
•
Digital signage—Enables innovative ways to publish content and information that improves the user
experience, allows dynamic updates, and increases campus safety and security. Some of the
common digital signage use cases in schools system include announcing school and district news,
major events, classroom assignments, PTA meetings, etc.
Figure 8-1 shows a Cisco DMS solution suite that is a set of product and technologies developed to
create an end-to-end digital media network. The products are divided into three major functions, create,
manage, and access.
Figure 8-1
Digital
Application
Cisco DMS Solution Suite
Create
Manage
Access
Cisco LCD
Display
Digital
Signage
Flash,
Shockwave,
HTML
Digital Media Manager
Digital Media
Player
Desktop
Video
Digital Media
Encoders
Cisco Video Portal
Cisco MCS
Cisco LCS
Display
Scientific Atlanta
Encoders
227853
Enterprise
TV
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The digital media components in the Cisco DMS solution suite assist schools in deploying digital media
solutions at their own pace; e.g., initially deploy digital signage with simple development applications
and deploy interactive video solutions in subsequent phases.
The Cisco Digital Media Manager (DMM) is a Web-based application that simplifies deploying all three
digital media applications in schools.
DMS Solution for Schools
DMS solutions in schools have proven valuable in overcoming key challenges in the development of
next-generation education delivery processes. DMS provides the flexibility to develop training content
that can be accessed by students anytime, and anywhere. Cisco DMS relies on a resilient, scalable, and
reliable network infrastructure for seamless end-to-end content delivery.
Figure 8-2 shows an end-to-end digital media reference model with all three applications enabling a
unified digital network service for the school district.
The following are some of the key benefits of this DMS design model:
•
Centralized management at the district office providing consistent publishing policies, security,
scalability. and reduced operational and maintenance cost.
•
Distributed storage and media access points enabling district office and schools to use centrally
developed content with reduced bandwidth capacity and increased availability during network
instability.
•
In large-scale video networks, the Cisco Application and Content Network Services (ACNS) or
WAN optimization appliances can be deployed to increase media performance and reduce expensive
WAN bandwidth requirements.
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Figure 8-2
End-to-End Reference DMS Solution in School Network Architecture
District Office
Admin
Lobby
Cafe
HDTV
HDTV
HDTV
HDTV
HDTV
HDTV
Data Center
Studio
Conference
Room
DMM
Internet
DMS
Admin
Web Server
Streaming
Server
Video
HDTV
MXE
CVP
Scientific Atlantic
Encoders
ADS/LDAP
Digital Media
Encoder
WAN
Regional School
Admin
Lobby
Cafe
HDTV
HDTV
HDTV
HDTV
HDTV
HDTV
Studio
Data Center
Classroom
HDTV
Web Server
Streaming
Server
Digital Media Encoder
Cafe
Video
HDTV
HDTV
School Web
Admin
Digital Signage
Enterprise TV
227854
Scientific Atlantic
Encoders
HDTV
Desktop Video
with Video Portal
Digital Media
Player
The following section provides an overview of various deployment scenarios, device components,
communication, and network requirements for digital media applications in schools. For a detailed
digital media design and implementation guide, refer to:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Video/DMS_DG/DMS_dg.html
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Desktop Video Application Overview
Students, teachers, and administrative staff can watch live or pre-recorded video events from their
personal computers at any location and at any time. The Cisco DMS Digital Video application empowers
faculty to extend the classroom audience to remote locations by broadcasting live or recording training
sessions available as video on-demand (VoD).
Cisco Desktop Video applications offer several benefits:
•
Customizable interface with program guide and search window.
•
Students can create a personalized video playlist.
•
Questions and comments can be made during live video broadcast events.
•
Restrict video content access based on Active Directory or LDAP authentication and privilege.
•
Wide format support—Adobe Flash, Windows Media, H.264, QuickTime, etc.
•
Player Controls—Synchronized slides, advanced video and controls, etc.
Desktop Video Components
As one of the integrated components of the Cisco DMS solution suite, the digital video application uses
common video development, management, and publishing components. In combination, external
authentication servers can provide secure, on-demand video content and live video broadcast services to
the desktop or on Cisco LCD TVs deployed in different physical locations.
The Cisco DMS solution suite consists of:
•
Digital Media Manager (DMM)—Centralized management appliance in district office governs the
content and communicates with local or remotely deployed critical desktop video components, e.g.,
CVP, HTTP server etc.
•
Digital Media Encoder (DME)—Single or multi-channel media encoder receives live analog/digital
feed from cameras or television service providers and transports over the IP network to the
streaming server.
•
Streaming Server—Provides stream splitting capabilities, allowing many clients to view a single
live stream from DME or pre-recorded source (replay)
•
Cisco Video Portal (CVP)—Web-based video navigation engine provides access to users after
successful authentication with Active Directory or LDAP server.
•
Web Server/Content Repository—Stores all VoDs referenced by Video Portal server. User triggers
VoD request to access video content through CVP and the request gets redirected to pull video file
from the content repository to the requested user.
Publishing Live and Video On-Demand Content
A critical feature of the Cisco Digital Media System for Cisco Desktop Video is its ability to simplify
the publishing of live and on-demand digital media files to the Cisco Video Portal (CVP). On-demand
video content can be uploaded from the developer’s computer directly to the DMM server for staging
and previewing prior to deployment. This staging capability includes the addition of an approval process
within the content workflow to help ensure that school branding, publishing policies, and messaging are
properly incorporated in the content. Post approval process, the content can be moved or deployed to the
Cisco Video Portal using secure file transmission.
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The Cisco DMM works in conjunction with Cisco Digital Media Encoders (DME) to create and deploy
live content to the Cisco Video Portal. The Cisco DMM first manages the Cisco DME to set up their
encoding profiles, defining the bit rate, format, and media type. The Cisco DMM also defines the port
that the Cisco Digital Media Encoders will stream from, so that the streaming servers can pull the stream
to their live publishing points. These publishing points are then deployed to the Cisco Video Portal
through the Cisco Digital Media Manager deployment process. The same workflow defined for the
on-demand digital media content is applied to live events, providing a consistent, easy-to-use process
for all types of deployments. Figure 8-3 shows a schematic of Cisco DMM video management.
Figure 8-3
VoD and Live Video Broadcast Using Digital Video Application
Video On-Demand (VoD)
Live Video Broadcast
Studio
Live
Video
Feed
Content
Sever
DME
DMS
Admin
DMM
Scientific Atlantic
Encoders
CVP
Video
ADS/LDAP
Portal Access
Multicast/HTTP
227855
HDTV
Enterprise TV Application Overview
The Enterprise TV (ETV) application brings standard or high-definition television network channels
into IP-based networks. Deploying Scientific Atlanta encoders in a video head-end role performs the
interworking function that transforms video source from television service provider to an IP based video
delivery within the campus network. When the ETV module is enabled in Cisco DMM appliance, the
school administrator can program the channel guide information to be broadcast in different physical
locations, e.g., channel number, name, port number, etc. To improve the user experience in navigating
video channels, ETV Electronic Program Guide (EPG) can be programmed to provide information on
channel lineup, and current and future programming information, which is similar to television service
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provided programming guide. To watch the live video channels, users can use Cisco DMP and remote
control to navigate and access the channel. Video delivery over IP networks can be unicast or multicast,
depending on how IP/multicast is designed in campus network.
With larger displays in key physical locations, the ETV application becomes the primary
communications interface in the district targeting large audiences. For example, live or VoD broadcast
for education training, demonstrations, meetings, etc., targeting all the students in a classroom, or live
news, etc.
Enterprise TV Components
To broadcast school developed VoD or live video through ETV, the core Cisco DMS components used
in the desktop video application can be leveraged to integrate ETV in the network. The primary
difference between ETV and desktop video in this case would be Digital Media Player (DMP) instead
of a PC as an access end point for a large screen display targeting a larger audience. To broadcast
television network channels in the campus network, the Scientific Atlanta encoder must be integrated
along with other ETV components. It is recommended to deploy distributed television service in local
campus and not forward non-critical video traffic over the WAN infrastructure.
•
Scientific Atlanta Encoder—An encoder system that provides interworking function between
analog or digital television service provider and IP network. Encodes live video input and
transforms into MPEG-2 or MPEG-4 multicast stream.
•
Cisco Digital Media Player (DMP)—Key media access end point that connects to Cisco LCD TV
for large size displays. DMP provides capabilities to decode multi-format graphics and stream video
content received over unicast or multicast IP network.
Broadcasting Live TV or Video On-Demand Content
The communication flow between the DMP and the DMM and Video Portal function is similar to
desktop video applications. Proper planning, technologies, and equipment must be deployed in campus
network for successful live television video delivery. When designing the playlist in Cisco Enterprise
TV module, the school administrator must understand that it can support up to 99 live and on-demand
video channels broadcast in the campus network. The DMM administrator in the district office can use
the DMM-ETV software module to create customized TV navigation interfaces, such as adding school
logo and skins, programming video channel assignments, and configuring specific video channel
assignment to DMP deployed in specific campus location. Figure 8-4 shows a schematic of the
Enterprise TV video architecture.
District and school architects must understand the codec type required for publishing video in the
campus network. Deployed digital encoders must follow the MPEG2 standard specification to stream
the video. It is recommended to deploy Scientific Atlanta 9032SD or 9050HD encoder to stream live
video stream to DMP for Enterprise TV application.
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Figure 8-4
Live Video Broadcast and VoD Using Enterprise TV Application
Video On-Demand (VoD)
Live Video Broadcast
Studio
Content
Sever
Live TV
Live
Video
Feed
DME
Set-Top-Box
DMS
Admin
DMM
Scientific Atlantic
Encoders
CVP
Live
Video
TV
ADS/LDAP
Portal Access
RTSP/HTTP/
Multicast
HDTV
HDTV
227856
HDTV
Digital Signage Application Overview
Cisco’s Digital Signage solution is a comprehensive solution for the publishing of dynamic and
on-demand signage using digital media displays deployed locally or regionally in schools over an IP
network. The key benefits of digital signage over traditional static signs in school are that the digital
content can be exchanged and updated more dynamically, using digital media tools to make the content
more relevant and interactive. Publishing school messages, local announcements, or emergency alerts
through Cisco digital signage becomes more effective and with better investment return compared to
traditional models.
The Cisco digital signage application is a Web-based media management and publishing application that
creates a playlist with a set of content that is required to be published to a single or group of DMPs in a
network. The digital signage application use standard HTTP protocols to communicate with centrally
deployed DMM in the district office data center and single or distributed Web servers to pull and publish
the real-time information to display on large Cisco LCD TVs. With flexible user administration, the
DMM administrator is empowered to create groups of users with different privileges who can develop,
publish, and manage the signage content; e.g., user group like school Web admin, IT admin, and security
admin can create content assets, control display properties, etc.
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Digital Signage Components
The requirements of the integrated digital media components depend on which content needs to be
published through a signage module. The Cisco digital signage application provides the flexibility for
the DMM administrator or school Web administrator to develop multi-functional, integrated content that
can play key messages, stream VoD files from a content server, and keep connected with external
information. For example, schools can publish a single Adobe flash file that is composed of static text
information, embedded with education short VoD stream and live news information with RSS feed. The
basic digital signage components are:
•
Digital Media Manager (DMM)—Centralized management appliance in district office governs the
content and communicate with local or remotely deployed critical desktop video components, e.g.,
CVP, HTTP server, etc.
•
Cisco Digital Media Player (DMP)—The Cisco DMP is a highly reliable IP-based hardware
endpoint for video decoding and playback of digital media content—including high-definition live
broadcasts and VoD, Flash animations, text tickers, and other Web content—across digital displays.
DMP is a critical component of the digital signage and ETV applications allow for the networking
of digital displays and the broadcasting of live and on-demand media. The current DMP portfolio
includes the Cisco DMP 4305G for standard signage and ETV and the Cisco DMP 4400G for
high-end signage and ETV.
•
Cisco LCD Professional Series—For an end-to-end Cisco digital media solution, the Cisco LCD
professional series displays is a high definition LCD display that can be centrally managed through
DMM.
•
Web Server/Content Repository—Stores all HTML, VoDs, flash files referenced by HTTP server
or Video Portal server. Multiple files can be played on same DMP; based on Web application design,
the program triggers the content request and it is pulled by DMP from a source server.
Video Surveillance System Architecture
The Cisco Video Surveillance solution relies on an IP network infrastructure to link all components. The
design of a highly available hierarchical network has been proven and tested for many years and allows
applications to converge on an intelligent and resilient infrastructure.
Figure 8-5 shows the main components of the Cisco Physical Security solution, including video
surveillance, physical access control, incident response and integration with third-party systems.
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Figure 8-5
Cisco Physical Security Components
Video and Device
Capture
Video Surveillance, Access Control
and Incident Management
Response
IP
IP Surveillance
Cameras
Safety and
Security
Physical Access
Manager Multiservices
Platform
Desktop
IP
IP
Third Party
Analog and IP
Cameras
Cisco Video
Surveillance
Operations
Manager (VSOM)
Open API - Third
Party Systems
IPICS
Multiservices
Platform
ISR - Video Media
Management and
Storage
Radios, Mobile Phones,
IP Phones
Digital Signage
227677
Physical Access
Gateway
Some of the benefits of Cisco’s Video Surveillance solution include the following:
•
Access to video at any time from any network location, enabling real-time incident response and
investigation.
•
Transfer of control and monitoring to any other point in the network in an emergency situation.
•
Ability to manage devices and alarms from a centralized location.
•
Ability for products from various vendors to interoperate in the same network.
•
An open, standards-based infrastructure that enables the deployment and control of new security
applications.
The main components of the Cisco Video Surveillance solution include the following:
•
Cisco Video Surveillance Media Server—The core component of the network-centric Video
Surveillance Manager solution. This software manages, stores, and delivers video from a wide range
of cameras and encoders over an IP network
•
Cisco Video Surveillance Operations Manager—The Operations Manager authenticates and
manages access to video feeds. It is a centralized administration tool for management of Media
Servers, Virtual Matrixes, cameras, encoders, and viewers and for viewing network-based video.
•
Cisco Video Surveillance IP Cameras—The high-resolution digital cameras are designed for
superior performance in a wide variety of environments.
•
Cisco Video Surveillance Virtual Matrix—The Virtual Matrix monitors video feeds in command
center and other 24-hour monitoring environments. It allows operators to control the video being
displayed on multiple local and remote monitors.
•
Cisco Video Surveillance Encoding Server—This all-in-one appliance encodes, distributes,
manages, and archives digital video feeds for analog cameras. Each server encodes up to 64
channels and provides up to 12 TB of storage.
•
Cisco Video Surveillance Storage System—This complementary component allows the Media
Server’s internal storage to be expanded with direct attached storage (DAS) and storage area
networks (SANs). The Storage System allows video to be secured and accessed locally or remotely.
The following subsections describe the components used for this solution.
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Cisco Video Surveillance Media Server
The Cisco Video Surveillance Media Server (VSMS) is the core component in the Cisco Video
Surveillance Manager solution and performs the following networked video surveillance system
functions:
•
Collection and routing of video from a wide range of third-party cameras and video encoders over
an IP network
•
Event-tagging and recording of video for review and archival purposes
•
Secure local, remote, and redundant video archive capabilities
In Figure 8-6, the Media Server is responsible for receiving video streams from different IP cameras and
encoders and replicating them as necessary to different viewers.
Figure 8-6
Video Surveillance Media Server (VSMS)
Media Server
(VSMS)
IP
IP
IP Cameras
Operations
Manager
(VSOM)
IP
D
A
Analog Cameras
OM Viewer
OM Viewer
227678
Encoder
By using the power and advanced capabilities of today’s IP networks, the Media Server software allows
third-party applications, additional users, cameras, and storage to be added over time. This system
flexibility and scalability supports the following:
•
Hundreds of simultaneous users viewing live or recorded video
•
Standard video compression algorithms such as MJPEG, MPEG-2, MPEG-4, and H.264
simultaneously via a single Media Server
•
Conservation of storage using events and loop-based archival options
•
Integration with other security applications
Cisco Video Surveillance Operations Manager
Working in conjunction with the Cisco Video Surveillance Media Server, the Cisco Video Surveillance
Operations Manager (VSOM) enables organizations to quickly and effectively configure, manage, and
view video streams throughout the enterprise. Figure 8-7 shows the Operations Manager main screen,
which is accessed through a Web browser.
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Figure 8-7
Video Surveillance Operations Manager
The Operations Manager meets the diverse needs of administrators, systems integrators, and operators
by providing the following:
•
Multiple Web-based consoles to configure, manage, display, and control video throughout a
customer’s IP network.
•
The ability to manage a large number of Cisco Video Surveillance Media Servers, Cisco Video
Surveillance Virtual Matrixes, cameras and users.
•
Customizable interface, ideal for branded application delivery.
•
Encoder and camera administration.
•
Scheduled and event-based video recording.
•
Interface to Media Server and Virtual Matrix software for pushing predefined views to multiple
monitors.
•
User and role management.
•
Live and archived video views.
•
Friendly user interface for PTZ controls and presets, digital zoom, and instant replay.
•
Event setup and event notifications.
•
“Record Now” feature while viewing live video
Cisco Video Surveillance IP Cameras
Cisco 2500 Series Video Surveillance IP Camera
The Cisco 2500 Series Video Surveillance IP camera is a high resolution standard-definition,
feature-rich digital camera designed for secure performance in a wide variety of environments. The
camera supports MPEG-4 and MJPEG compressions with up to 30 frames per second.
Contact closure and two-way audio allow integration with microphones, speakers, and access control
systems. By providing wired and wireless models, the Cisco 2500 IP camera provides an ideal platform
for integration and operation as an independent device or as part of the Cisco Video Surveillance
network. Figure 8-8 shows both the wired and wireless models of the 2500 IP Camera.
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Figure 8-8
Cisco 2500 Series IP Cameras
The 2500 Series IP camera provides the following features:
•
The camera employs powerful digital imaging technology, allowing it to capture high-quality
images in a wide variety of indoor and outdoor lighting conditions. It uses a progressive scan
image-sensor with global electronic shuttering to ensure natural color rendition, and minimal
motion blurring.
•
The wireless IP camera model supports 1X2 Multiple Input Multiple Output (MIMO)
communication, which provides better data throughput and higher link range than single antenna
designs. The wireless IP camera offers strong wireless security using Wi-Fi Protected Access
(WPA)/WPA2 and supports various network protocols for 802.1x authentication.
•
Power over Ethernet (PoE) 802.3af or DC power through an optional external power supply.
•
Support for the Cisco Media API, an open, standards-based interface that allows integration with
compatible video surveillance management systems.
•
Support for 802.1x authentication on both the wired and wireless models.
Cisco 4000 Series Video Surveillance IP Camera
The Cisco Video Surveillance 4000 Series IP Cameras employ true high-definition (HD) video and
H.264 compression, streaming up to 30 frames per second at 1080p (1920 x 1080) resolution. The Cisco
4000 IP Camera series also supports contact closure and two-way audio allow integration with
microphones, speakers, and access control systems.
The Cisco 4000 Series includes two models: the CIVS-IPC-4300 and CIVS-IPC-4500. These cameras
have identical feature sets, with the exception of the additional digital signal processor capabilities
specifically designed to support real-time video analytics at the edge on the CIVS-IPC-4500. On this
model, applications and end users have the option to run multiple analytics packages without
compromising video streaming performance on the camera.
Figure 8-9 shows a Cisco 4000 IP Camera with an optional DC Auto Iris Lens.
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Figure 8-9
Cisco 4000 Series IP Camera
The 4000 Series IP camera provides the following features:
•
True high-definition video—The camera streams crisp and clear 1080p (1920 x 1080) video at 30
frames per second while maintaining surprisingly low network bandwidth.
•
Progressive scan video—The camera captures each frame at its entire resolution using progressive
scan rather than interlaced video capture, which captures each field of video.
•
Embedded security and networking—The camera provides hardware-based Advanced Encryption
Standard (AES).
•
IP Multicast for enhanced bandwidth management.
•
Event notification—The camera can examine designated areas for activity and notify users or other
applications when it detects activity that exceeds a predefined sensitivity and threshold.
•
True day/night functionality that includes an infrared (IR) filter that automatically switches to night
mode in low light scenes.
•
The camera supports Power-over-Ethernet (PoE) 802.3af, 12 VDC or 24 VAC power through an
optional external power supply.
•
The camera can be installed with a fixed mount or with an optional external pan/tilt mount and
motorized zoom lens.
For more information, see the Physical Safety for Schools Application Deployment Guide:
http://www.cisco.com/en/US/docs/solutions/Verticals/Education/safe_sec_ed_dg.html
Deploying Digital Signage in School Campus
To ensure a successful digital media deployment, network, display, and management planning must be
done prior to deploying digital signage in the schools network. A well-planned digital signage network
design provides flexibility to incrementally deploy desktop video and ETV digital media applications
without making major infrastructure changes. As described earlier, digital signage uses standard HTTP
protocols to pull and publish the signage content on displays. Network bandwidth consumption for
digital signs varies widely as it depends on playlist and content types. This document provides the best
practices to design and configure the digital signage with content developed with rich text, flash, and
animation and located on distributed Web servers to increase network efficiency.
Centralized Management Model
Cisco DMM is highly scalable appliance server that can be deployed centrally in district office location
to manage up to 1000 DMPs deployed in local and regional school campus network. Cisco DMP
deployed in local district offices or remote regional schools can communicate with centralized DMM
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over LAN and WAN network using standard HTTP as the control protocol to receive Web or content
server re-direction information to display content. Deploying DMM in a centralized location allows the
DMM administrators in district offices to manage all registered DMP in various ways:
•
Add and archive digital content and assign metadata and keywords.
•
Create and manage play lists, ticker alerts, messages, closed captions, and promotional interstitials.
•
Preview digital signage content and manage approval workflow.
•
Ability to pre-configure the playlist and schedule for instant and future deployments.
•
Take WAN optimization solution advantage and provide tight integration with Cisco ACNS and
Cisco Content Engines.
•
Manage user administrator accounts and permissions.
Centralizing DMP management and publishing signage content centrally at a district office allows the
DMM administrator to advertise consistent information and messaging throughout the network. To
minimize WAN network utilization, the school administrator must leverage internal storage or their
local Web server to store and advertise the local, regional, and department news and information.
However the district office and Internet news must be communicated over the WAN.
The network architect must consider integrating enterprise-class Cisco Application and Content
Networking System (ACNS) that uses caching technology and offers higher scalability and reliable
video delivery solution at the schools to improve end user experience and application response time.
When integrated with the Cisco Wide-Area Application Services (WAAS) solution, it helps in
optimizing WAN bandwidth utilization significantly with local redirection and high data compression
over the WAN.
Figure 8-10 is a validated design to integrate digital signage with centralized management in the district
office with distributed DMP in a large-scale school network.
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Figure 8-10
Centralized DMM with Distributed DMP in School SRA
District Office
Admin
Lobby
HDTV
Cafe
HDTV
HDTV
Data Center
Conference
Room
DMS
Admin
DMM
HDTV
ADS/LDAP
Web Server
HTTP
Regional Office
Admin
Lobby
HDTV
Cafe
HDTV
HDTV
Server Room
227857
Web Server
School
Web
Admin
Distributed Content Storage Model
Digital signage content is typically wrapped with HTML or Adobe Flash applications that provide
greater flexibility for a Web administrator to display more types of content from various sources on a
single page. When deploying large numbers of DMPs with rich and static digital signage content, the
unicast communication between DMP and the distributed content server may waste network bandwidth
by retrieving the same content for continuous display. Hence it becomes important for the network
architect to understand the content distribution and network level requirements to optimally deploy
signage application in a campus network.
Depending on DMP scalability, overall network capacity, and the bandwidth allocation for digital
signage application, Cisco DMS offers the following three distributed content storage solutions for
Cisco DMP to pull and display the static content from the local network instead of downloading all of it
through the WAN network:
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•
Cisco DMS-Content Distribution (CD)—Is an ideal solution for a small-scale school network with
few Cisco DMPs. Cisco DMM can push the static HTML or flash content via FTP or SFTP protocol
to Cisco DMM on internal storage or to external storage device like USB drive and redirect Cisco
DMP to access internal storage. This solution helps to minimize WAN bandwidth utilization.
•
Local Content Server (Web or CIFS)—Storing the digital media content on a single local content
server, like HTTP or CIFS sever, gives the network administrator more flexibility and management
of the content distribution solution. The Web administrator can dynamically add, modify, and store
the updated HTML or Flash file on a centralized server for Cisco DMP to retrieve and display. On
the next HTTP request from DMP, the refreshed copy is displayed automatically. This solution
provides more flexibility compared to Cisco DMS-CD solution, as it can dynamically update
content without updating and managing content on each individual Cisco DMP.
•
Cisco ACNS—Highly scalable and intelligent large size video content distribution to remote
locations. Hierarchical content distribution system at district office and school sites distributes
single copy of pre-recorded video to ACNS edge at the schools. To increase WAN network
efficiency, Cisco ACNS leverages the caching technology and provides unicast VoD delivery in
local LAN networks to end users instead of downloading one copy for each user over the WAN
network.
SRA Validated Content Distribution Model
To provide a simplified, scalable, and cost-effective content distribution and management solution in
SRA architecture, it is recommended to leverage local Web or CISF servers in the district office and
schools to store and publish local digital signage content. Cisco DMM can be programmed to re-direct
local DMPs to a local Web server and remote DMPs to pull the content from a local Web server. Such
distributed content storage design minimizes the critical WAN bandwidth usage to publish local
information. However, the WAN network may still be utilized to access global signage information,
such as county or state level education and emergency news that can be broadcast by Web server from
district office, and similarly real-time news ticker from the Internet can be embedded in major content
that provides constant world-wide news updates.
School network architects and Web administrators must perform pre-deployment exercise to assess the
type of local versus distributed content (text/graphics/VoD/RSS) embedded in signage and the number
of DMPs to be deployed in schools. This assessment provides WAN bandwidth guidelines to integrate
digital signage in schools. As described earlier, Cisco WAN optimization solution like ACNS and
WAAS must be integrated in the network if it demands higher WAN bandwidth. Figure 8-11 depicts the
unicast communication flow between Cisco DMP deployed across the network and Web servers located
in intranet and Internet domains.
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Figure 8-11
Distributed Content Server Communication
Intranet Content Server Communication
Admin
Lobby
HDTV
Internet Content Server Communication
Cafe
HDTV
Data Center
Admin
HDTV
HDTV
HDTV
Cafe
HDTV
Data Center
Conference
Room
Web Server
Lobby
Conference
Room
HDTV
Internet
District Office
District Office
WAN
WAN
Regional School
Admin
HDTV
Regional School
Lobby
HDTV
Cafe
HDTV
Admin
HDTV
Lobby
HDTV
Cafe
HDTV
HDTV
Server Room
Web Server
227858
School
Web
Admin
Implementing Network Services for Digital Signage
Prior to integrating digital signage applications, the network architect must make network services ready
with the best practices for resilient and seamless operation and integration. Building the network as a
highly-available platform is a foundational requirement for applications like IP telephony and digital
media solutions as they demand constant bandwidth and network availability. Deploying centralized
DMM with a distributed content server spans the digital communication beyond the campus boundary;
hence it is recommended to deploy digital media solutions based on these network design principles:
•
Low latency—Deploy the high-speed campus network that offers lower latency for real-time
applications like voice and video.
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•
High availability—To increase network resiliency it is recommended to deploy the network with
redundant modules, systems, and power supplies offering non-stop communication and sub-second
network recovery during minor or major network failure events.
•
QoS—Enhance user experience and content quality with robust QoS policies at the campus network
edge.
•
Confidentiality—Protect digital media end points, appliances, and data with centralized
authentication and encryption.
This section provides access ayer design and configuration guidelines to deploy Cisco DMP at the
campus network edge and DMM in a centralized data center in a district office. For more information
on design and implementation guideline for building a strong and resilient core and foundational campus
network, refer to the following URL:
http://www.cisco.com/en/US/docs/solutions/Verticals/Education/SRA_Schools/school_sra_campus_dg
.pdf
Deploying Cisco DMP in the Access Layer Network
Cisco DMP is a school managed and trusted end point in the campus access layer, hence the network
administrator must apply the common security and QoS policy for DMP as defined for other trusted
end-points like IP phones. In a typical deployment scenario, a single access layer switch may be
connected to several other trusted and un-trusted end-points, hence it becomes an important task for
administrator to provide secure and suitable network services.
Cisco access layer switches provides the flexibility to deploy Cisco DMP in two different modes, manual
deployment and plug-and-play Auto Smartport (ASP) macro.
Manual Deployment
School administrator must manually implement the following three major network services to
successfully integrate DMP in the network:
•
Assigning unique Layer 2 VLAN
•
Implement network edge security
•
Implement network edge QoS
Assigning Unique Layer 2 VLAN
To provide secured and simplified digital signage communication, the DMP must be assigned a unique
broadcast domain. De-coupling DMP with other trusted and un-trusted end points makes DMP more
secure during any attacks and is easier to manage and troubleshoot. When single access layer connects
to multiple DMPs, then all the DMPs can be assigned on the same Layer 2 VLAN. Like any other logical
network partition design, it is recommended to use unique Layer 2 VLAN for DMP that are physically
deployed on different Cisco access layer switches. Figure 8-12 provides recommended Cisco DMP
Layer 2 segmentation guidelines in the access-layer:
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Cisco DMP-Layer 2 VLAN Segmentation
Access
Lobby
DMP
VLAN 10
Access
Cafe
DMP-1
Cafe
DMP-2
Cafe
DMP-3
VLAN 20
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Figure 8-12
Cisco DMP cannot transmit or receive 802.1Q tagged frames, hence it is recommended to change default
switchport mode from dynamic to access mode. The following is a sample configuration to enable
VLAN in the database and apply VLAN on the DMP physical port:
2960
cr24-2960-DO(config-if)#interface FastEthernet0/7
cr24-2960-DO(config-if)# description CONNECTED TO LOBBY DMP
cr24-2960-DO(config-if)# switchport mode access
cr24-2960-DO(config-if)# spanning-tree portfast
cr24-2960-DO(config-if)# switchport access vlan 10
3750
cr25-3750-DO(config-if)#interface range GigabitEthernet 1/0/1 - 3
cr25-3750-DO(config-if-range)# switchport mode access
cr25-3750-DO(config-if-range)# spanning-tree portfast
cr25-3750-DO(config-if-range)# switchport access vlan 20
For flexible and scalable DMP deployment, it is recommended that the DMP edge port be in Layer 2
mode even when the access layer switch is deployed in a multilayer or routed access network design.
Implement Network Edge Security
Cisco DMP player is an extremely silent system and it requires communication with certain critical
systems in the network, such as an IP gateway, Cisco DMM, Web servers, SNM, and NTP. To display
the digital signage content and synchronize with management servers, Cisco DMP receives more data
from the network than transmitting to the network.
Cisco Catalyst integrated security feature must be deployed on the physical port to protect DMP from
being attacked by viruses or unauthorized hosts. Based on the protocol and data communication
characteristics of Cisco DMP, it is recommended to apply the following set of security configurations to
protect the network and the DMP from unknown traffic floods and attacks:
Access
interface FastEthernet0/7
! Block transmitting all unknown unicast traffic
switchport block unicast
! Enable port-security on this port
switchport port-security
! Default, allow single-host to access this port
switchport port-security maximum 1
! Block receiving BPDU from this port
spanning-tree bpduguard enable
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Implement Network Edge QoS
It is important to implement differential service treatment for digital media applications over non-critical
network traffic in the network. Depending on the digital media applications and the distributed content,
appropriate QoS services must be implemented at the network edge that connects media end-points and
in the data center where typically centralized management and content servers are deployed. As
described earlier, the Cisco DMP primarily use standard HTTP protocol to communicate with
centralized DMM management server and the distributed Web server to publish the digital signage
content.
By default, HTTP packets between digital media end-points are set with default DSCP values and rely
on intermediate network devices to classify the traffic and provide advanced QoS techniques to protect
the digital media communication between DMP and other back end systems. Since the communication
and publish content is delivered using HTTP protocol, it becomes challenging to distinguish between
HTTP control traffic versus digital content in the campus network. Following RFC 4594 QoS
deployment guidelines, the unicast control plane communication between Cisco DMM and DMP system
can be classified as signaling traffic and must be marked an appropriate DSCP value and assigned a
proper queue. Figure 8-13 provides QoS references to deploy digital media application in a campus
network:
Digital Signage QoS Reference Chart
Application
Class
PHB
Admission
Control
Congestion Managment
and
Congestion Avoidance
Cisco Video Applications
VoIP Telephony
EF
Required
Priority Queue (PQ)
Broadcast Video
CS5
Required
Optional (PQ)
Cisco DMS (Live Streams)/Enterprise TV/IPVS
Realtime Interactive
CS4
Required
Optional (PQ)
Cisco TelePresence
Multimedia Conferencing
AF4
Required
BW Queue + DSCP WRED
Cisco CUPC/CUVA/CI IP Phone 7985G
Multimedia Streaming
AF3
Recommended
BW Queue + DSCP WRED
Cisco DMS (VoDs)
Network Control
CS6
BW Queue
Call-Signaling
CS3*
BW Queue
OAM
CS2
BW Queue
Transactional Data
AF2
BW Queue + DSCP WRED
Bulk Data
AF1
BW Queue + DSCP WRED
Best Effort
DF
Best
Effort+ RED
Default
Queue
Best
Effort
Scavenger
DF
CS1
Best Effort
Min BW Queue
(Deferential)
DMM/DMP Control Traffic
Cisco WebEx/CU MeetingPlace
Effort
YouTube/Xbox Best
Live/iTunes/BitTorent/etc.
227860
Figure 8-13
*Cisco classification method slightly differs from RFC 4594. CS3 and CS5 definition are interchanged.
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Applying Ingress QoS Policy on DMP and DMM Port
Network QoS policies must be set at the campus access edge to mark recommended DSCP bit for control
or management traffic between DMM and DMP. HTML or Flash based digital signage content can
remain in same best-effort class. The control traffic can be identified from digital signage content based
on TCP flow between Cisco DMM and DMP. Figure 8-14 provides QoS marking guidelines between
Cisco DMP, Cisco DMM appliance, and content server:
Figure 8-14
QoS Marking Between Digital Signage Components
DMP
HDTV
DSCP=CS3
DSCP=DF
DSCP=DF
Internet
Web Server
DMM-DMP Control Traffic
DMP-Content Server Traffic
227861
DMM
Based on TCP and static Cisco DMM and DMP player information, the following configuration
guideline must be implement QoS policy on access layer switches that connect to Cisco DMP and Cisco
DMM in a centralized data center:
! Classify DMP and DMM HTTP traffic with extended ACL
ip access-list extended DMS-SIGNALING
remark DMM-DMP-MGMT
permit tcp host <DMP-IP-Address> host <DMM-IP-Address>
permit tcp host <DMM-IP-Address> host <DMP-IP-Address>
!
class-map DMS-SIGNALING
match access-group name DMS-SIGNALING
!
policy-map DMS-Policy
class DMS-SIGNALING
set dscp cs3 ? Explicit mark DSCP CS3
!
interface FastEthernet0/7
description CONNECTED TO LOBBY DMP
mls qos trust dscp
service-policy input DMS-Policy?Apply ingress service-policy
!
interface FastEthernet0/10
description CONNECTED TO Cisco DMM Appliance
mls qos trust dscp
service-policy input DMS-Policy?Apply ingress service-policy
cr24-3560r-DO#show mls qos interface fas0/7 | inc policy-map|dscp
Attached policy-map for Ingress: DMS-Policy
trust state: trust dscp
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trust mode: trust dscp
Additional ingress QoS policies, such as policers, can be implemented on access switches if the network
administrator is concerned about securing the restricting ports to consume higher bandwidth.
Applying Egress QoS Policy on DMP and DMM Port
Ingress QoS policy helps the network to distinguish between HTTP control and digital media content
traffic within the campus backbone. Similar QoS techniques are required to provide differential services
between control and digital media content traffic exiting the port connected to Cisco DMP and DMM
appliance on the access layer switches. For global egress policy for trusted and un-trusted device, it is
recommended to share the egress bandwidth to each hardware queue and enable prioritization for the
low-latency traffic:
cr24-3560r-DO(config)#interface FastEthernet0/7
cr24-3560r-DO(config-if)# srr-queue bandwidth share 1 30 35 5 ? Enable BW share
cr24-3560r-DO(config)#priority-queue out? Enable Priority-Queueing
cr24-3560r-DO#show mls qos interface fast0/7 queueing
FastEthernet0/7
Egress Priority Queue : enabled
Shaped queue weights (absolute) : 25 0 0 0
Shared queue weights : 1 30 35 5
The port bandwidth limit : 100 (Operational Bandwidth:100.0)
The port is mapped to qset : 1
To deploy QoS in a school campus network design, refer to the following URL:
http://www.cisco.com/en/US/docs/solutions/Verticals/Education/SRA_Schools/SchoolSRA_QoS_sba.
pdf
Auto Smartport Macro Deployment
Cisco access layer switches provide a zero-touch or plug-n-play type network provisioning solution by
dynamically detecting connected end-points and automatically applying best practices and
recommended configurations. Cisco Auto Smartport macro helps network architects to reduce the
number of challenges in implementation when deploying complex configurations. Cisco validated
design comprehensively validates multiple set of tools and technologies to solve the critical business
problems. Cisco Auto Smartport leverages validated and recommended network configuration and
parameters that dynamically provision the network without any user intervention. Implementing
recommended and validated configuration parameters helps school network administrators to
automatically provide network and device security and optimize application performance.
Cisco Auto Smartport leverages several Layer 2 protocol techniques to dynamically detect the end-point
platform that intelligently triggers the function and applies the configuration from pre-defined
recommended templates. To further increase operational efficiency, Cisco Auto Smartport removes all
dynamically applied configurations when the device is un-plugged or removed from the network. The
following is the list of Layer 2 technologies and end-point types that Cisco Auto Smartport macros use
to dynamically apply configurations:
•
Layer 2 Technologies
– Cisco Discovery Protocol (CDP)
– IEEE AB - LLDP
– 802.1x
– MAC-Authentication Bypass (MAB)
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– Layer 2 Source MAC address
– Ethernet OUI
•
Supported End-Point Platforms
– IP Phones—Cisco and Avaya IP Phone
– Wireless Access-Points—Cisco AP 11xx series
– IP Video Surveillance—Cisco IPVS 25xx and 4xxx series camera
– Digital Media Player—Cisco DMP 4x00 series players
This section focuses on providing guidelines for the basic configuration needed to enable Cisco Auto
Smartport to dynamically provision Cisco DMP in the network.
Cisco Auto Smartport macro leverages a simple shell function to execute the pre-defined configuration
template embedded in the switch for each type of supported end-point. Cisco DMP configuration gets
executed dynamically based on the port event triggers. The following output provides the Auto
Smartport event trigger and dynamic configuration guideline when it detects Cisco DMP on the physical
port:
cr26-3750#show shell functions CISCO_DMP_AUTO_SMARTPORT
function CISCO_DMP_AUTO_SMARTPORT () {
!!Provision this configuration when Link up event is triggered
!!and Cisco DMP is detected:
if [[ $LINKUP -eq YES ]]; then
conf t
interface $INTERFACE
macro description $TRIGGER
switchport access vlan $ACCESS_VLAN
switchport mode access
switchport block unicast
mls qos trust dscp
spanning-tree portfast
switchport port-security
switchport port-security maximum 1
switchport port-security violation shutdown
spanning-tree bpduguard enable
priority-queue out
exit
end
fi
!!Remove dynamic configuration when Link Down event is triggered.
if [[ $LINKUP -eq NO ]]; then
conf t
interface $INTERFACE
no macro description
no switchport access vlan $ACCESS_VLAN
no switchport block unicast
no switchport port-security
no switchport port-security maximum 1
no switchport port-security violation shutdown
no mls qos trust dscp
no spanning-tree portfast
no spanning-tree bpduguard enable
no priority-queue out
if [[ $AUTH_ENABLED -eq NO ]]; then
no switchport mode access
fi
exit
end
fi
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}
Comparing the Auto Smartport macro configuration with a recommended manual configuration, it can
be seen that the majority of the recommended manual configuration is in the macro template. Some of
the advanced QoS parameters, such as MQC-based DSCP marking, may have to be manually configured.
Implementing Auto SmartPort Macro
School network administrators must enable Cisco Auto SmartPort Macro function along with basic
network parameters on access layer switches to dynamically detect and provision the configuration for
various types of end-points. Enabling Cisco Auto Smartport macro function globally enables all the
physical ports and provisions and un-provisions the network configuration for the Cisco DMP based on
shell triggers and functions. It also provides the flexibility to disable the Auto Smartport function on a
per-port basis where the static configuration is required. The following is the simple global configuration
to enable Cisco Auto Smartport processing for all the physical ports:
3750
cr26-3750(config)#macro auto global processing
cr26-3750#show macro auto interface | inc Auto
Global Auto Smart Port Status
Auto Smart Ports Enabled
As described earlier, Cisco Auto Smartport can leverage multiple Layer 2 technologies to detect the
end-points, by default Auto SmartPort use the pre-defined MAC address-group range to dynamically
detect the Cisco DMP based on Ethernet OUI address. To deploy Cisco DMP based on Ethernet OUI,
no additional configuration is required. To enable secure access-control solution, Cisco Secure ACS and
MAB can be integrated to authenticate Cisco DMP based on registered MAC address in the ACS
database.
cr26-3750#show macro auto address-group CISCO_DMP_EVENT
MAC Address Group Configuration:
Group Name
OUI
MAC ADDRESS
-------------------------------------------------------------------------CISCO_DMP_EVENT 0023.AC
000F.44
Because some of the network parameters like VLAN IDs are unique in the network, the school
administrator needs to determine the common VLAN ID to deploy for a common set of end points. For
example, when Cisco DMP is detected on Switch1, then it must dynamically detect the media player and
assign it to appropriate VLAN and execute the network configuration template. By default, when Cisco
Auto Smartport detects the Cisco DMP device on the port it configures the port in access-mode and
assigned it a default VLAN ID = 1. After applying following single global configuration, the Auto
Smartport automatically assigns all the Cisco DMP in to user-defined VLAN.
cr26-3750(config)#macro auto device media-player ACCESS_VLAN=58
cr26-3750#show macro auto device media-player | inc Device|ACCESS
Device:media-player
Configurable Parameters:ACCESS_VLAN
Defaults Parameters:ACCESS_VLAN=1
Current Parameters:ACCESS_VLAN=58
Tuning Auto SmartPort Macro
Cisco Auto Smartport is optimized in detecting the end points and provisioning the configuration for
rapid and error-free deployments. The shell function that performs the configuration provisioning and
un-provisioning task is based on physical link up and down events. In initial deployment, the end-points
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can be detected using different Layer 2 techniques and all dynamically provisioned configurations can
be saved in configuration files. Due to its nature the configuration is removed and then the same
configuration is re-applied when the link goes down temporarily for any common reason, e.g., link flap,
end-point is power cycled, etc.
To make configuration persistent during such a link flap, the following single global configuration can
be applied to retain the dynamic configuration during a link flap:
cr26-3750(config)#macro auto sticky
Implementing Cisco Digital Media Player
Once the recommended network edge configuration on the access layer is implemented, the Cisco DMP
is ready to be deployed. Since Cisco DMP uses an embedded Linux OS which is not accessible directly
to end users, the basic network parameters must be provisioned using Web-based Cisco DMP-Device
Manager (DM). The Cisco DMP-DM is divided into three major configuration modes:
•
Settings (Network/Browser/Storage)
•
Display
•
DMP Administration
The school administrator must configure the basic network parameters to deploy Cisco DMP in
production network; the DMM administrator from the district office can apply the global display and
management parameters to DMP without intervening school administrator for any advanced
configuration task.
This chapter provides the following deployment guidelines to successfully deploy Cisco DMP and Cisco
DMM appliance server communication in the network:
•
Assigning IP address to Cisco DMP
•
Registering Cisco DMP to Cisco DMM database
Assigning IP Address to Cisco DMP
The default IP setting on Cisco DMP is to dynamically acquire IP address and gateway information from
DHCP server. It is recommended to assign a unique static IP address to DMP as it provides flexibility
to the network administrator to provide secured DMP-DM GUI access with ACLs and the ability to
provide distinguished QoS treatment for control traffic between Cisco DMP and DMM appliance server.
Figure 8-15 is a simple IP configuration task that the school administrator must perform to change the
default IP address method from DHCP to static IP address mode:
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Figure 8-15
Assigning DMP Static IP Address
Registering Cisco DMP to Cisco DMM Database
The first step to enable communication between digital signage components is to register network wide
deployed Cisco DMP into the centralized Cisco DMM appliance database. Cisco DMM appliance
requires basic information from Cisco DMM to register—MAC and IP address firmware version and
storage information. Centralized DMM appliance can register large numbers of DMPs across the school
network and it may become an operational challenge to manage each DMP player. DMM administrator
can create a logical DMP group along with the range of IP subnet; DMM-DSM automatically groups the
registered DMPs based on assigned IP address. The following are some of the advantages in deploying
DMP group in school architecture:
•
Organize registered DMPs into a single logical group.
•
Instead of managing each individual DMP, the DMP group allows the DMM administrator to
manage a group of DMPs collectively.
•
Accelerate digital signage content deployment and instruction to the DMP group instead of
individual players.
•
Like content management, common display attributes to all DMPs in the DMP group.
The Cisco DMS solution provides flexibility to the DMM administrator for manual or automatic Cisco
DMP registration into the database. Depending on the number of Cisco DMP deployed across the
network, either of the registration process can be selected.
•
Manual DMP Registration—The DMM administrator must manually enter Cisco DMP MAC and IP
address information into the DMM database. For better operational management and
troubleshooting, the DMP must be assigned to an logical DMP groups.
•
Auto DMP Registration—Is a highly scalable, simplified, and error-free DMP registration solution
for large deployments. To auto-register and auto-group the DMP in user-defined groups, the range
of IP subnets or CIDR ranges must be specified to scan the Cisco DMP players in the network.
Multiple IP subnets can be configured for single DMP group. The DMM appliance transmits TCP
based unicast packet with pre-defined port number 7777 to scan Cisco DMP, which cannot be
modified by the user. Hence for successful auto-registration process, it is recommended to make
sure TCP port 7777 is not filtered anywhere in the network. The DMM admin can control the DMM
appliance to trigger on-demand or schedule scan to locate DMP in the network for auto registration.
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The DMM admin must complete these three steps sequentially to successfully deploy DMM groups and
auto DMP registration in the DMM-DSM:
Step 1
Configure DMM Group and assign an IP subnet.
Figure 8-16
Step 2
Configure DMP Discovery Application and assign an IP subnet.
Figure 8-17
Step 3
Configuring DMP Group Using DMM-DSM
Configuring DMP Discovery Application
Trigger the DMP discovery with manual action or schedule to discover in future.
Manual DMP Discovery Trigger
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Figure 8-18
Triggering DMP Discovery Manually
Refreshing the window in few seconds will reflect the dynamically discovered Cisco DMP that gets
automatically registered and grouped as depicted in Figure 8-19. The default name of the auto-registered
DMP is the same as their MAC address; the DMM admin must change to reflect with proper name or
location name.
Figure 8-19
Dynamically Discovered DMP Discovery Triggered Manually
Scheduling DMP Discovery
Depending on the number of DMP groups, network ranges, and DMP players in the network, the DMP
discovery may take some time. In large deployments, it is recommended to schedule Cisco DMP
discovery during non-business hours. Scheduling DMP discovery in the network is identical to
scheduling the digital signage publishing time. To schedule DMP discovery using Cisco DMM-DSM:
1.
Click on Schedules ->Play in Future->Select discovery month and date
2.
Select the DMP group to be discovered->Click on Add an Event Button.
3.
Select DMP group from Select Group Tab and click OK.
4.
Select Advanced Task from Task Type Tab and click on Select Advanced Tasks Tab.
5.
Select DMP Discovery from Types and the Action Name and click OK.
6.
Configure Start and Stop Action run time and optionally configure repeat value to dynamically
discover Cisco DMP based on schedule.
Implementing Digital Signage
Upon successfully discovering and registering the Cisco DMP in the DMM appliance database, the
DMM administrator can start preparing to implement digital signage in the network. The provision
checklist must include exact content path and schedule to display the content on individual or group
DMP in the network. As described earlier, the content must be stored on a Web or CISF server that is
physically located on the same campus network as a Cisco DMP. Hence when creating the playlists, it
is recommended to specify the URL path where the content is stored.
Publishing digital signage requires three simple configuration step on DMM-DSM as depicted in
Figure 8-20:
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Figure 8-20
Digital Signage Deployment Steps
Executing each step populates content information in DMM in the common repository, provides
flexibility to compile playlist with distributed content, and schedules the digital signage publishing time
by mapping the playlist to individual or group DMPs. The network topology in Figure 8-21 is used as a
reference point to configure each deployment step.
Figure 8-21
Digital Signage Network Topology
District Office
Admin
Lobby
HDTV
Cafe
HDTV
Data Center
DMS
Admin
DMM
HDTV
Conference
Room
HDTV
creekcountyschools.com
Web/CISF
Server
WAN
Regional Office
Admin
Lobby
HDTV
Cafe
HDTV
HDTV
Server Room
Web/CISF
Server
227868
creek.rosenelementary.com
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Step 1
Adding Asset in Media Library.
Cisco DMM-DSM builds an asset of digital media content in a common Media Library database.
Figure 8-22 provides information about the variety of digital media content types supported and can be
stored in two major locations—remote Web/CISF content server or it must be uploaded to local DMM
appliance server. As described earlier, the recommended content distribution model is to keep content
distributed on remote servers that reside on the same LAN as Cisco DMPs. Cisco DMM appliance must
not be used as a content server. Each asset type must be entered one at a time in the media library. Each
asset is executed serially within the playlist; the Cisco DMM-DSM also provides flexibility to publish
digital signage content in random order.
Figure 8-22
Supported Asset Types
Execute the following steps to add distributed digital signage (non-video) content asset into Media
Library:
1.
Click on Add Media Asset Button.
2.
Click on Single Tab.
3.
Click URL in radio button as a Source and type the exact URL to access content (e.g.,
http://creek.rosenelemetary.com/default.html). Prior to deploying, the content must be tested and
verified by applying same URL from local internet browser.
4.
Do not click on download check box. This will prevent downloading provided HTTP URL content
to the local DMM hard-drive.
5.
Select File Type from drop down window based on URL extension.
6.
Enter estimated or planned playback time for this asset.
7.
Select the media category from Category window in which this URL fits in.
8.
Optionally, provide description and content owner/developer information.
9.
Click on Save button to review the entered information.
10. Click the Close button to exit the window.
Step 2
Creating Playlist.
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Playlist is a user-defined logical group that is packaged with the compiled list of distributed digital
signage assets which are being added in the shared Media Library database. For example, a playlist can
include the intranet home page of the district office and regional school and library books catalog
developed in Adobe Flash.
Cisco DMM-DSM provides the flexibility to develop playlists in two different modes—Standalone and
Cisco Digital Media Designer (DMD). When the digital signage content is designed and developed
outside the DMM-DMD, then DMM administrator must create a standalone playlist.
Cisco Digital Media Designer (DMD) is a Java-based, powerful, drag and drop design tool to create
customized digital signage content. Cisco DMM offers pre-designed assets that can be leverage to create
personalized design. DMD also offers flexibility to customized horizontal and vertical screen display
orientation.
Figure 8-23
Digital Signage Playlist Options
This section provides guideline to implement a standalone playlist. Multiple playlists can be created and
associated to an individual or group of DMPs. When designing the asset in the playlist, it is important
to remember that the content publishing time and mappings to DMP groups are applied based on
per-playlist and not on per-asset basis. The order of playlist execution is done serially based on specified
time. Figure 8-24 depicts the playlist order and duration time on per-cycle basis.
Figure 8-24
Digital Signage Display Order and Duration
In a best practice, the playlist can be created based on individual district office or school departments
that can provide flexibility to announce the news or any other department specific content at specific
time without impacting the playlist for other DMP groups deployed in different departments. Execute
the following steps to compile the distributed digital signage asset and estimated or planned run time for
each individual asset.
Click on Create Playlist button and follow step-by-step instruction provided in Figure 8-25 to create a
complied and distributed digital signage content in playlist.
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Figure 8-25
Step 3
Compiling Assets with Standalone Playlist
Scheduling Playlist.
After successfully completing the above two steps the URL of distributed digital signage content is
added in media library database and the playlist is compiled with the list of signage content that needs
to be played for DMP group. The DMM administrator can send the playback command in two different
modes—Instant Play and Future Play.
Instant Play or “Play Now” sends the playback command to selected DMP groups and all the DMPs can
start displaying digital signage content immediately. Instant Play option provides an option for
immediate signage content deployment; it can also be used to publish the newly added or updated
signage asset in an already playing playlist. When Cisco DMP receives the new and updated playlist
command from centralized DMM appliance, it aborts playing the previous playlist commands and
immediately starts the display based on new information.
Future Play or “Play in Future” gives flexibility to the DMM administrator to pre-deploy digital signage
in the DMM appliance database and schedule to play the playlist on a pre-determined month, date, or
specific time. For example, you could have next month’s café lunch menu automatically published in
the last week of the current month.
Figure 8-26 depicts tab selection to schedule the playlist in both deployments modes.
Figure 8-26
Playlist Scheduling Modes
Implementing Instant Play mode
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Execute the step-by-step procedure as depicted in Figure 8-27 to deploy digital signage instantly in the
network. Cisco DMM-DSM provides the flexibility to select single, multiple, or all the DMPs using
shift-key to instantaneously publish digital signage in large deployments.
Figure 8-27
Publishing Instant Digital Signage
Implementing Future Play mode
Click on Play in Future tab to schedule a future digital signage content publishing time. Click on Add
an Event button from the bottom window and follow the step-by-step configuration guideline as
displayed in Figure 8-28 to schedule future signage deployment:
Figure 8-28
Scheduling Signage Deployment
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9
Access Layer Security Design
One of the most vulnerable points of the network is the access edge. The access layer is where end users
connect to the network. In the past, network administrators have largely relied on physical security to
protect this part of the network. Unauthorized users were not allowed to enter a secure building where
they could plug into the network, and students didn't carry computers with them. Today, contractors and
consultants regularly have access to secure areas, and a student carrying a laptop is unsurprising. Once
inside, there is nothing to prevent a contractor or student from plugging into a wall jack and gaining
access to the corporate network. There is no need to enter an employee office to do this. Conference
rooms frequently offer network access through wall jacks or even desktop switches. Once connected to
the network, everyone (employees, contractors, consultants, guests, students, and malicious users) has
access to all the resources on the network.
What is commonly called the access layer in network design is the business end of the network, the part
of the network that your users see and interact with. The end users do not see or appreciate the power of
your collapsed core distribution layer, the elegance of your addressing plans, or the genius of your end
to end network design. Your more technical users may be able to identify an RJ-45 port or WLAN access
point if asked, but most users simply expect the network to be there. Training users on using the access
is focused upon small—the smaller the better—number of steps users must go through to gain access to
their network applications.
At the same time as providing simple uncomplicated network access for users, the access layer provides
the first line of security defense for the network, provide service differentiation based upon management
policies and, providing power to support the deployment of specialized devices.
The roles can be broken broadly into the following areas:
•
Access layer security
•
Access layer QoS
•
Access layer Power-over-Ethernet (PoE)
Access Layer Security
The access layer is where your client’s network devices directly connect to your network. You want their
connection to be as efficient, simple, and secure as possible. This involves controlling who accesses the
network and for what services. Controlling access may be as simple as blocking access, or it may involve
a redirection or quarantining action.
To continue the general security metaphor part of controlling the boundary is also observing
inappropriate behavior at the boundary can also result in blocked access.
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The Schools SRA uses the native Cisco switch features and Cisco security products to provide boundary
control services. The primary tools for access layer security in the schools are as follows:
•
Catalyst Integrated Security Features (CISF)
•
Cisco Clean Access (NAC)
•
Cisco Identity-Based Network Networking Services (IBNS)
When implementing the security features, consideration needs to be made upon the client requirements
using the access layer. In the Schools SRA, the following client connections are considered:
•
Ethernet PC client ports
•
Printer ports
•
IP phone ports
•
Wireless clients
•
AP ports
•
Access layer PoE
•
Access layer QoS
Catalyst Integrated Security Features (CISF) Protected Ports
Catalyst Integrated Security Features (CISF) includes private VLANs, port security, DHCP snooping,
IPSource Guard, secure Address Resolution Protocol (ARP) detection, and dynamic ARP inspection.
These features protect the network against attacks such as man-in-the-middle, spoofing, and
infrastructure denial-of-service (DoS) attacks.
•
Port Security—Where the number of MAC addresses allows on a switch port is monitored, and the
switch can respond to violations with management messages and changes in the port state.
•
DHCP snooping—Where DHCP messages are inspected, and filtered to ensure that DHCP server
messages only come from a trusted interface.
•
IPSource Guard—Where the IP traffic is restricted based upon DHCP or static IP address MAC
bindings to ensure a host doesn't attempt to use the IP address of a neighboring host
•
Dynamic ARP inspection—Where the all ARP packets from untrusted interfaces are inspected to
ensure that they contain valid MAC address and IP address pairings, preventing ARP spoofing
attacks
•
ARP rate limiting—Where an excessive rate of ARP request (which must be processed by network
hosts CPUs), and the switch responds with access restriction if this rate is exceeded.
•
Storm Control—Prevents traffic on a LAN from being disrupted by a broadcast, multicast, or unicast
storm
CISF Port Configuration
switchport port-security maximum 2
switchport port-security
switchport port-security aging time 2
switchport port-security violation restrict
switchport port-security aging type inactivity
ip arp inspection limit rate 100
ip dhcp snooping limit rate 100
storm-control broadcast level 20.00 10.00
storm-control multicast level 50.00 30.00
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NAC Protected Ports
This section discusses he Cisco NAC Appliance (also known as Cisco Clean Access) in the Schools
SRA. It is not intended to be a comprehensive guide on the Cisco NAC Appliance solution itself. This
chapter focuses on general NAC Appliance design principles and how they apply to components of the
Schools SRA.
Cisco NAC Appliance is an easily deployed NAC product that uses the network infrastructure to enforce
security policy compliance on all devices seeking to access network computing resources. With Cisco
NAC Appliance, network administrators can authenticate, authorize, evaluate, and remediate wired,
wireless, and remote users and their machines prior to network access. The Cisco NAC Appliance
identifies whether networked devices such as laptops, or IP phones are compliant with network security
policies, and repairs any vulnerabilities before permitting access to the network.
When deployed, the Cisco NAC Appliance provides the following benefits:
•
Recognizes users, their devices, and their roles in the network. This first step occurs at the point of
authentication, before malicious code can cause damage.
•
Evaluates whether machines are compliant with security policies. Security policies can include
specific anti-virus or anti-spyware software, OS updates, or patches. Cisco NAC Appliance supports
policies that vary by user type, device type, or operating system.
•
Enforces security policies by blocking, isolating, and repairing non-compliant machines.
•
Non-compliant machines are redirected to a quarantine network, where remediation occurs at the
discretion of the administrator.
Figure 9-1 shows the following four key functions of the NAC:
•
Authenticate and authorize
•
Scan and evaluate
•
Quarantine and enforce
•
Update and remediate
Figure 9-1
The Four Functions of the NAC Framework
Authenticate and Authorize
Scan and Evaluate
• Enforces authorization
policies and privilges
• Agent scan for required versions
of hotfixes, AV, etc.
• Supports multiple user roles
• Network scan for virus
and worm infections and
port vulnerbilities
Quarantine and Enforce
• Isolate non-compliant devices
from rest of network
• Network-based tools for
vulnerbility and threat
remediation
• Help-desk integration
227497
• MAC and IP-based quarantine
effective at a per-user level
Update and Remediate
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For a more in-depth overview of the Clean Access Server and Clean Access Manager, see the following
URLs:
•
Cisco NAC Appliance-Clean Access Server Installation and Administration Guide
http://www.cisco.com/application/pdf/en/us/guest/products/ps7122/c1626/ccmigration_09186a008
07a4090.pdf
•
Cisco NAC Appliance-Clean Access Manager Installation and Administration Guide
http://www.cisco.com/en/US/docs/security/nac/appliance/configuration_guide/45/cam/45cam-boo
k.html
Cisco Clean Access Components
Cisco NAC Appliance is a network-centric integrated solution administered from the Cisco Clean
Access Manager web console and enforced through the Clean Access Server and (optionally) the Clean
Access Agent or Cisco NAC Web Agent. Cisco NAC Appliance checks client systems, enforces network
requirements, distributes patches and antivirus software, and quarantines vulnerable or infected clients
for remediation before clients access the network. Cisco NAC Appliance consists of the components
shown in Figure 9-2.
Figure 9-2
NAC Components (Source Document NAC CAM Configuration Guide)
Internet
Switch
L2
Router
L3
eth1
Firewall
eth0
LAN/Intranet
Clean Access
Server (CAS)
PCs with
Clean Access
Agent (CAA)
Clean Access
Manager (CAM)
Authentication sources
(LDAP, RADIUS, Kerberos,
WindowsNT)
Admin laptop
DNS
server
227498
Clean Access Manager
Web admin console
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Clean Access Manager (CAM)
CAM is the administration server for Clean Access deployment. The secure web console of the Clean
Access Manager is the single point of management for up to 20 Clean Access Servers in a deployment
(or 40 CASs if installing a SuperCAM). For Out-of-Band (OOB) deployment, the web admin console
allows you to control switches and VLAN assignment of user ports through the use of SNMP. In the
Schools SRA, the CAM would be located at the district office.
Clean Access Server (CAS)
CAS is the enforcement server between the untrusted (managed) network and the trusted network. The
CAS enforces the policies you have defined in the CAM web admin console, including network access
privileges, authentication requirements, bandwidth restrictions, and Clean Access system requirements.
You can install a CAS as either a standalone appliance (like the Cisco NAC-3300 Series) or as a network
module (Cisco NME-NAC-K9) in a Cisco ISR chassis and deploy it in-band (always inline with user
traffic) or OOB (inline with user traffic only during authentication/posture assessment).
The CAS can also be deployed in Layer 2 mode (users are Layer-2-adjacent to CAS) or Layer 3 mode
(users are multiple Layer-3 hops away from the CAS). You can also deploy several CASs of varying
size/capacity to fit the needs of varying network segments. You can install Cisco NAC-3300 Series
appliances in your company headquarters core, for example to handle thousands of users and
simultaneously install one or more Cisco NAC network modules in ISR platforms to accommodate
smaller groups of users at a satellite office, for example.
In the Schools SRA, the CAS would be located at the schools sites and the district office, and it would
be used to provide Layer-2 or Layer-3 OOB authentication/posture assessment.
Clean Access Agent (CAA)
CAA is optional read-only agent that resides on Windows clients. It checks applications, files, services,
or registry keys to ensure that clients meets your specified network and software requirements prior to
gaining access to the network.
Note
There is no client firewall restriction with CAA posture assessment. The agent can check the client
registry, services, and applications even if a personal firewall is installed and running.
If NAC is implemented as part of the Schools SRA it is recommended that the CAA be used.
Cisco NAC Web Agent
The Cisco NAC Web Agent provides temporal posture assessment for client machines. Users launch the
Cisco NAC Web Agent executable, which installs the Web Agent files in a temporary directory on the
client machine via ActiveX control or Java applet. When the user terminates the Web Agent session, the
Web Agent logs the user off of the network and their user ID disappears from the Online Users list.
Clean Access Policy Updates
Regular updates of prepackaged policies/rules that can be used to check the up-to-date status of
operating systems, antivirus (AV), antispyware (AS), and other client software. Provides built-in
support for 24 AV vendors and 17 AS vendors.
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NAC Appliance Modes and Positioning
NAC Appliance allows multiple deployment options and may be placed at different points in the
network. The modes of operation can be generally defined as follows:
•
Out-of-band (OOB) virtual gateway
•
OOB IP gateway
•
In-band (IB) virtual gateway
•
IB real IP gateway
OOB Modes
OOB deployments require user traffic to traverse through the NAC Appliance only during
authentication, posture assessment, and remediation. When a user is authenticated and passes all policy
checks, their traffic is switched normally through the network and bypasses the appliance. See
Figure 9-3.
Figure 9-3
Layer-2 OOB Topology
VLAN 10
MGR
VLAN 10
VLAN 900
VLAN 110
802.1q Trunk
VLANs 110 and 10
VLAN 110
Authentication and
Posture Assessment
221297
VLAN 10
Authenticated
Network Access
To deploy the NAC Appliance in this manner, the client device must be directly connected to the
network via a Catalyst switch port. After the user is authenticated and passes posture assessment, the
Clean Access Manager (CAM) instructs the switch to map the user port from an unauthenticated VLAN
(which switches or routes user traffic to the NAC) to an authenticated (authorized) VLAN that offers full
access privileges. For example, as shown in Figure 9-3, the client PC is connected through VLAN 110
to the NAC Clean Access Server for the authentication and posture assessment, and is moved to VLAN
10 once it successfully completes the authentication and authorize, and scan and evaluation phases of
the NAC framework.
In-Band Modes
When the NAC Appliance is deployed in-band, all user traffic, both unauthenticated and authenticated,
passes through the NAC Appliance, which may be positioned logically or physically between end users
and the network(s) being protected. See Figure 9-4 for a logical in-band topology example and
Figure 9-5 for a physical in-band topology example.
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Figure 9-4
In-Band Virtual Gateway Topology
VLAN 10
MGR
VLAN 10
VLAN 900
VLAN 110
VLAN 110
Posture Assessment
Authenticated Access
Figure 9-5
221298
VLAN 110
Physical In-Band Topology
VLAN 10
MGR
VLAN 900
VLAN 10
Posture Assessment
Authenticated Access
221299
VLAN 110
In-Band Virtual Gateway
When the NAC Appliance is configured as a virtual gateway, it acts as a bridge between end users and
the default gateway (router) for the client subnet being managed. The following two bridging options
are supported by the NAC Appliance:
•
Transparent—For a given client VLAN, the NAC Appliance bridges traffic from its untrusted
interface to its trusted interface. Because the appliance is aware of “upper layer protocols”, by
default it blocks all traffic except for Bridge Protocol Data Unit (BPDU) frames (spanning tree) and
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those protocols explicitly permitted in the “unauthorized” role; for example, DNS and DHCP. In
other words, it permits those protocols that are necessary for a client to connect to the network,
authenticate, undergo posture assessment, and remediation. This option is viable when the NAC
Appliance is positioned physically in-band between end users and the upstream network(s) being
protected, as shown in Figure 5.
•
VLAN mapping—This is similar in behavior to the transparent method except that rather than
bridging the same VLAN from the untrusted side to the trusted side of the appliance, two VLANs
are used. For example, Client VLAN 131 is defined for the untrusted interface of the NAC
Appliance. There is no routed interface or switched virtual interface (SVI) associated with VLAN
131. VLAN 31 is configured between the trusted interface of the NAC Appliance and the next-hop
router interface/SVI for the client subnet. A mapping rule is made in the NAC Appliance that
forwards packets arriving on VLAN 131 and forwards them out VLAN 31 by swapping VLAN tag
information. The process is reversed for packets returning to the client. Note that in this mode,
BPDUs are not passed from the untrusted-side VLANs to their trusted-side counterparts.
The VLAN mapping option is usually selected when the NAC Appliance is positioned logically in-band
between clients and the networks being protected. This is the bridging option that should be used if the
NAC Appliance is going to be deployed in the virtual gateway mode.
In-Band Real IP Gateway
When the NAC Appliance is configured as a “real” IP gateway, it behaves like a router and forwards
packets between its interfaces. In this scenario, one or more client VLAN/subnets reside behind the
untrusted interface. The NAC Appliance acts as a default gateway for all clients residing on those
networks. Conversely, a single VLAN/subnet is defined on the trusted interface, which represents the
path to the protected upstream network(s).
After successful client authentication and posture assessment, the NAC Appliance by default routes
traffic from the untrusted networks to the trusted interface, where it is then forwarded based on the
routing topology of the network.
The NAC Appliance is not currently able to support dynamic routing protocols. As such, static routes
must be configured within the trusted side of the Layer 3 network for each client subnet terminating on
or residing behind the untrusted interface. These static routes should reference, as a next hop, the IP
address of the trusted interface of the NAC.
If one or more Layer-3 hops exist between the untrusted NAC interface and the end-client subnets, static
routes to the client networks must be configured in the NAC Appliance. Likewise, a static default route
(0/0) is required within the downstream Layer 3 network (referencing the IP address of the untrusted
NAC interface) to facilitate default routing behavior from the client networks to the NAC Appliance.
Depending on the topology, multiple options exist to facilitate routing to and from the NAC Appliance,
including static routes, VRF-Lite, MPLS VPN, and other segmentation techniques. It is beyond the
scope of this design guide to examine all possible methods.
In-Band Versus Out-of-Band
Table 9-1 summarizes different characteristics of each type of deployment.
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Table 9-1
In-Band Versus Out-of-Band Deployment Characteristics
In-Band Deployment Characteristics
Out-of-Band Deployment Characteristics
The Clean Access Server (CAS) is always inline with
user traffic (both before and following authentication,
posture assessment and remediation). Enforcement is
achieved through being inline with traffic.
The Clean Access Server (CAS) is inline with user traffic only
during the process of authentication, assessment and remediation.
Following that, user traffic does not come to the CAS.
Enforcement is achieved through the use of SNMP to control
switches and VLAN assignments to ports.
The CAS can be used to securely control authenticated The CAS can control user traffic during the authentication,
and unauthenticated user traffic by using traffic policies assessment and remediation phase, but cannot do so
post-remediation since the traffic is out-of-band.
(based on port, protocol, subnet), bandwidth policies,
and so on.
Does not provide switch port level control
Provides port-level control by assigning ports to specific VLANs
as necessary
In-Band deployment is supported when deploying for
wireless networks
Wireless OOB requires a specific network topology and
configuration.
Cisco NAC Appliance In-Band deployment with
supported Cisco switches is compatible with 802.1x
Cisco does not recommend using 802.1x in an OOB deployment,
as conflicts will likely exist between Cisco NAC Appliance OOB
and 802.1x to set the VLAN on the switch interfaces/ports.
Out-of-Band Requirements
OOB implementation of Cisco NAC Appliance requires the switches and Wireless LAN Controllers be
supported by the Cisco NAC Appliance software. All the switches tested as part of the development of
the Schools SRA, apart from the Cisco Catalyst 2975, are supported by the Cisco NAC OOB, and the
Wireless LAN Controllers are also supported by the NAC Appliance software used in this design guide.
If the Catalyst 2975 is to be used as an access switch with the Cisco NAC Appliance, the NAC solution
must be an in-band solution.
Note
To obtain the latest list of supported devices, check the latest version of the Cisco NAC Appliance-Clean
Access Manager Installation and Administration Guide at the following URL:
http://www.cisco.com/en/US/docs/security/nac/appliance/configuration_guide/45/cam/45cam-book.ht
ml
Out-Of-Band, Layer 2 and Layer 3
The proposed design for the Schools SRA is an OOB design, in order the highest possible performance
and scalability for traffic that has passed through the authentication, posture assessment, and
remediation stages of NAC. The Schools SRA offers two different access layer options, a Layer-2 access
layer for smaller schools and a hybrid Layer-2/Layer-3 access layer for larger schools. This means that
either a Layer-2 OOB solution or a Layer-3 OOB NAC solution may be deployed.
NAC Deployment in the Schools SRA
The Schools SRA provides for a Cisco NAC Appliance solution at each site type, District Office, School
Site 1, and School Site 2, with a CAM at the District Office, and a CAS at the District Office and Schools
Sites. In each of the different site types the CAS is directly connected to the core/distribution.
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The simple topology used in the Schools SRA sites means that a VLAN from an access layer to the
untrusted interface of the NAC Appliance is always available as a standard component of the design, and
untrusted traffic should never need to be tunneled to the CAS. This allows a common the network
configuration, to support NAC at any of the School sites, regardless of whether the client devices are
using a Layer-2 or Layer-3 access model. As the client can use a Layer-2 connection to the untrusted
interface of the NAS in either Layer 2 or Layer 3 access mode (this requires a trunk between the Layer-3
access switch and the core/distribution. One VLAN of the trunk would carry the untrusted VLAN, and
the other VLAN the IP routing for all other traffic), and the VLAN used once the client is trusted will
be either be a Layer-2 access VLAN from the core/distribution switch or a Layer-3 access switch VLAN
depending upon the site requirements.
This is illustrated in Figure 9-6 and Figure 9-7. In Figure 9-6, there is a simple Layer-2 NAC OOB
connection where a client device upon initial connection to the network is given VLAN 264, which
connects them directly to the untrusted interface of the NAS. The mapping of this interface through the
NAC VLAN 64 trusted interface allows the client to obtain an IP address that belongs on VLAN 64. To
perform any action permitted by an untrusted client, upon success completion of the NAC function, the
access switch is instructed, via SNMP, to change the client VLAN to VLAN 64. Even though the client
has changed Layer-2 VLANs its Layer-3 network connections are unchanged.
In Figure 9-7, the same processes are followed when the client is untrusted, but once the client has
successfully completed its NAC functions the access switch is instructed via SNMP to change the client
VLAN to VLAN 67—a subnet local to the access switch. As the Layer-3 information for the client has
changed the switch is also instructed to “bounce” the client switch port to initiate a new DHCP request
for an IP address appropriate to VLAN 67.
Figure 9-6
Layer 2 OOB topology
VLAN 264
L2 Untrusted
227499
L2 Trusted
VLAN 64
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Figure 9-7
Layer 3 OOB Topology
VLAN 264
L2 Untrusted
L2 Trusted
VLAN 64
227500
L3 Trusted
VLAN 67
Configuring the CAS and CAM
The initial CAS and CAM configuration are done via directly on the server interface, and this is
described in the installation guide, Cisco NAC Appliance Hardware Installation, Release 4.1. During the
configuration stage the multiple steps must be followed in configuring the NAC Appliance with IP
addresses, VLANs. passwords, etc. The installation guide contains worksheets assist in the gathering
and preparation of this information for both the CAM and CAS.
Once the CAM(s) and CAS(s) are configured they can be configured by their web interfaces. Almost all
of the NAC Appliance solution can be configured through the CAM, and it have be access via HTTPS
to the IP address assigned during the appliance configuration stages.
The first task on the CAM before beginning configuration is the installation the licenses for the solution.
A license must be installed for the CAM, and the CAS servers that the CAM control. The Cisco NAC
Appliance Ordering Guide, provides information on the ordering options.
Licenses can be entered via the CAM web interface, as show in Figure 9-8.
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Figure 9-8
NAC Appliance Licensing
Adding a CAS to the CAM
For a CAS server to be managed by the CAM, it must be added to the list of managed servers on the
CAM. To do this the CAM needs to know the IP address of the CAS, and the Server Type (its role in the
network) of the CAS. In addition to this the CAS and the CAM must have the same shared secret. The
shared secret is configured during the server installation. An example of adding a CAS to the CAM, is
shown in Figure 9-9.
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Figure 9-9
Adding a new CAS to the CAM
Once the CAS has been added to the CAM, it appears in the list of servers on the CAM. From this point,
it can be managed directly from the CAM for almost all tasks. An example of a list of servers is shown
in Figure 9-10.
Figure 9-10
List of CAS Servers
Managing the CAS
Once the CAS is in the list of servers managed by the CAM, it can be configured further for its role in
the network. To manage the server click the icon under the Manage heading in the server list, this will
connect you to the CAS server and present you with the summary menu shown in Figure 9-11.
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Figure 9-11
CAS Management Menu
Under the CAS Network setting tab, shown in Figure 9-12. the basic network settings for the CAS can
be seen and altered, if needed. In this example, we are keeping the network configuration performed
during the server installation. The primary dialog under the Network Tab is the IP dialog, shown in
Figure 9-12, the other dialogs allow the DHCP options to the configured—our example uses the default
of DHCP passthrough— and the DNS options where host name, domain name, and DNS server
information is added, as shown in Figure 9-13.
Figure 9-12
CAS Network Settings
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Figure 9-13
CAS DNS Settings
The next tab in the CAS configuration is the Filter tab (see Figure 9-14), for the purposes of our example
the important dialog is the Roles where network traffic filters may be applied to different user Roles.
The Role of interest at this moment is the default Unauthenticated Role. By default the Unauthenticated
Role blocks all traffic. In this example we are allowing the Unauthenticated Role to pass Active
Directory client authentication traffic to pass to the Active Directory Sever. This will allow a windows
client to join the active Directory Domain, and windows users to authenticate to the domain although
they have not been through the NAC process. This is often important to allow printer and drive mapping
information to be sent to the winders users. As the user has already authenticated to the Active Directory
Domain the user authentication information maybe learned from Active Directory, and the user does not
have to reauthenticate for the NAC server.
Note
The creation of Roles and their associated filters is performed in the CAM User Management -> User
Roles menu.
Figure 9-14
CAS Filter Settings
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The next tab that requires configuration is the Advanced tab. This has multiple dialogs that require
configuration. The first of these is the Managed Subnet dialog, where each of the trusted VLAN subnets
is added to the CAS for management. An example of this shown in Figure 9-15.
Figure 9-15
CAS Managed Subnet
The next dialog of the Advanced Tab is the VLAN Mapping dialog, which tells the CAS which trusted
VLAN to be mapped to an untrusted VLAN, an example of this is shown in Figure 9-16. In our example
VLAN Prunning and VLAN Mapping is also enabled.
Figure 9-16
VLAN Mapping
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The next tab of interest is the Authentication Tab (see Figure 9-17), this tab has multiple dialogs for
configuring different authentication options. The first dialog is the Login Page Dialog. This allows the
configuration of different web login pages depending upon the untrusted subnet being used for
authenticating client.
Figure 9-17
Authentication Login Page
The other Authentication dialog of interest in this example is the Windows Auth dialog, as Windows
Single Sign On (SSO) is used in this example. To perform Windows SSO the CAS needs to be able to
communicate with Active Directory to determine the authentication state of the windows user. If Active
Directory confirms that the user has authenticated to Active Directory the user doesn't need to perform
additional authentication to the CAS. An example of this configuration is shown in Figure 9-18. There
are a number of steps required configure Active Directory SSO, as these are described in the Cisco NAC
Appliance —Clean Access Server Installation and Configuration Guide. The key components in this
configuration are:
•
The creation of a Active Directory client account for the CAS
•
Using the KTPass Application on Active Directory to convert the account encryption to DES
encryption
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Figure 9-18
CAS Windows Authentication
Clean Access Roles
The unauthenticated role is common to all clients, but once the client has been authenticated a different
role may be applied based upon the identity of the client, different roles may be assigned for admin staff,
teachers, or students.
User roles allow you to aggregate various policies into a user role. These policies include:
•
Traffic policies
•
Bandwidth policies
If bandwidth policies are to be enforced by the Clean Access Server it must be operating in band.
Note
•
VLAN ID retagging
•
Clean Access network port scanning plugins
•
Clean Access Agent/Cisco NAC Web Agent client system requirements
For example, an Admin, Teacher and Student roles could each have different traffic polices and VLANs,
in addition the Student Role may enforce bandwidth policies by keeping the Student Traffic In band.
For more information on roles, refer to the Cisco NAC Appliance - Clean Access Manager Installation
and Configuration Guide at the following URL:
http://www.cisco.com/en/US/docs/security/nac/appliance/configuration_guide/45/cam/45cam-book.ht
ml
Layer 2 OOB Example
Figure 9-19 shows an example of a Layer-2 OOB deployment. Where a wired client connected to an
access switch is originally on the untrusted VLAN 264 and is switched to a trusted VLAN 64 once it has
completed the NAC functions. The first NAC function is the authentication and authorization function,
and this is the first design decision in implementing the NAC solution. That is, how will authentication
and authorization be achieved, and what will the user experience be.
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This example is focused upon the virtual gateway example, as virtual gateway provides the simplest
deployment. In the virtual gateway example the original IP addressing, interfaces, and VLANs are
maintained, and normal traffic flows are maintained. The only changes are the addition of the untrusted
VLANs that carry client traffic during the NAC Authentication and Authorization, Scanning and
evaluation, remediation, and quarantine modes.
Figure 9-19
CAM
10.40.94.15
Layer 2 OOB Example
AD
MetroE
School District Network
VLAN 264
L2 Untrusted
CAS
L2 Trusted
VLAN 64
VLAN 64
227512
VLAN 264
NAC Authentication Options
The authentication option in the NAC solution can be broadly categorized as NAC Authentication or
NAC Single Sign On
•
NAC Authentication—NAC authentication gives the NAC system the role of authenticating users, a
user database, either local to the NAC system or a separate system such as RADIUS, or LDAP
•
NAC Single Sign On—NAC SSO, addresses systems that already perform authentication as part of
their normal operation. For example 802.1X, VPN access, or Active Directory. NAC SSO learns the
authentication state of clients through RADIUS accounting, or Active Director and therefore doesn't
require the user to reenter authentication.
Topology Considerations
The Layer-2 OOB solution relies upon their being a Layer-2 network connection available between the
the client devices and the Cisco CAS, in figure 5 a trunk connects the access switch to the
core/distribution switch. The Cisco CAS is connected to the core/distribution switch through two
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interfaces—trusted and untrusted. In such a simple network it is relatively easy to provide a Layer-2
connection between the client and the Cisco CAS, for larger networks Layer-3 OOB, which is discussed
later in this section, may be a better choice.
The roles of the untrusted and trusted interfaces:
•
Untrusted Interface—The untrusted interface connects the client to the to the Cisco CAS during the
NAC Authentication and Authorization, Scanning and Evaluation, Remediation, and Quarantine
modes
•
Trusted Interface—The trusted interface connects the NAC CAS to the “normal” network interface.
This makes a network connection available to the CAS while it is sitting between the client and the
network, thus allowing client access to services such as DHCP and DNS -and user defined services.
Once a client has successfully completed its authentication and scanning phases, the CAM uses
SNMP to change the client VLAN, on the access switch, from the untrusted VLAN to the trusted
VLAN. Thus providing a direct connection to the network that was on the other side of the CAS (the
trusted network).
Availability Considerations
Both the CAS and CAM are both highly involved in client network access, and consideration must be
given to the impact on clients if either a CAS or CAM should fail or need to be taken out of service for
a period of time.
The CAS is inline with client devices during the authentication, authorization, and posture assessment
phases of NAC, and if “In Band NAC” is being used it may be inline at all times. A CAS outage in an
OOB deployment would not impact already connected clients but would prevent network access for new
clients. A CAS outage for “In Line” clients prevents access for all clients.
In situations where availability of a CAS is critical an HA CAS solution may be implemented where a
pair of CAS servers are installed using a primary CAS, and a secondary in hot standby. For more
information refer to the Cisco NAC Appliance - Clean Access Server Installation and Configuration
Guide.
The CAM is also a critical part of the authentication, authorization, and posture assessment phases of
NAC, although it doesn't pass client traffic, it the impact of its availability needs to be considered in the
network design as well. Like the CAS the CAM has a HA solution that provides for a primary server and
a hot standby secondary server. In addition, each CAS may be configured with a “fallback” option (as
shown in Figure 9-20) that defines how it will manage client traffic in a situation where the CAM is
unavailable.
In both HA CAM, and HA CAS, HA licenses are use that address the HA role of the server.
The use of the HA features will be dependent upon a Schools requirements, but CAS fallback should
always configured to ensure that critical network services are available in even of a network outage.
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Figure 9-20
CAS Fallback
Basic Clean Access switch Configuration
For OOB-based Clean Access some simple configuration must be performed on the switches
implementing NAC This configuration is primarily to enable SNMP communication between the
switches and the CAM. Table 9-2 shows a simple SNMP v1 configuration (SNMPv2c and SNMPv3 are
supported).
In addition to the switch SNMP configuration, the required trusted and untrusted VLANs must exist and
be operational on the switch. If a switch has more than one IP address the snmp-server source interface
must be specified, as the CAM must be configured with the source IP address that OOB SNMP messages
will originate from, alternatively all IP addresses of interfaces on the switch can be added to the CAM.
If SNMP access filtering is applied on the switch (as recommended as a best practice) the CAM must be
added as a trusted address.
Basic Clean Access Out of Band Switch configuration
Table 9-2
SNMPv1 Configuration
Switch Port Configuration
Global Switch Configuration
snmp trap mac-notification
change added
snmp-server enable traps mac-notification
snmp-server enable traps snmp linkup linkdown
mac-address-table aging-time 3600
snmp-server host 172.16.1.61 traps version 1 cam_v1
udp-port 162 mac-notification snmp
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802.1X Protected Ports
The best and most secure solution to vulnerability at the access edge is to leverage the intelligence of
the network. The Cisco IBNS solution is a set of Cisco IOS software services designed to enable secure
user and host access to enterprise networks powered by Cisco Catalyst switches and wireless LANs. It
provides standards-based network access control at the access layer by using the 802.1X protocol to
secure the physical ports where end users connect. 802.1X is an IEEE standard for media-level (Layer
2) access control, offering the capability to permit or deny network connectivity based on the identity of
the end user or device. 802.1X is well-known as a way to secure wireless network access. It is equally
essential in securing wired network access.
What is 802.1X?
The IEEE 802.1X protocol allows Cisco Catalyst switches to offer network access control at the port
level. Every port on the switch is individually enabled or disabled based on the identity of the user or
device connecting to it. When 802.1X is first enabled on a port, the switch automatically drops all traffic
received on that port. There is one exception to this rule. The only traffic a switch will accept is a request
to start 802.1X authentication. Only after the 802.1X authentication has successfully completed will the
switch accept any other kind of traffic on the port.
The high-level message exchange in Figure 9-21 illustrates how port-based access control works within
an identity-based system. First, a client, such as a laptop equipped with an 802.1X supplicant, connects
to an IEEE 802.1X-enabled network and sends a start message to the LAN switch the authenticator.
Once the start message is received, the LAN switch sends a login request to the client and the client
replies with a login response. The switch forwards the response to the policy database authentication
server which authenticates the user. After the user identity is confirmed, the policy database authorizes
network access for the user and informs the LAN switch. The LAN switch then enables the port
connected to the client.
Figure 9-21
Port-Based Access Control
7 Switch Enables Port
Authentication
Server
Authenticator
1 EAPOL Start
2 Login Request
3 Login Response
4 Check with Policy DB
5 Policy DB Confirms
ID and Grants Access
227515
6 Policy DB Informs Switch
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User or device credentials are processed by a AAA server. The AAA server is able to reference user or
device policy profile information either internally, using the integrated user database, or externally,
using database sources such as Microsoft Active Directory, LDAP, Novell NDS or Oracle databases.
This enables the integration of the system into exiting user management structures and schemes, thereby
simplifying overall deployment.
802.1X and EAP
When authenticating users for the purposes of network access control, the system must provide user
and/or device identification using strong authentication technologies known to be secure and reliable.
IEEE 802.1X does not by itself dictate how this is achieved. Rather, the 802.1X protocol defines an
encapsulation for the transport of the Extensible Authentication Protocol (EAP) from the client to the
switch. The 802.1X encapsulation is sometimes referred to as EAP over LAN (EAPoL). The switch in
turn relays the EAP information to the authentication server using the RADIUS protocol (EAP over
RADIUS).
EAP, which is defined by RFC 3748, is itself a framework---not a specific authentication method. EAP
provides a way for the client and the authentication server to negotiate an authentication method that
they both support. There are many EAP methods but the ones used more frequently for 802.1X wired
authentication include EAP-TLS, EAP-PEAP, and EAP-FAST.
How 802.1X Impacts the Network
Before enabling 802.1X in the network, it is essential to review the default security posture of a port
enabled for 802.1X authentication: all traffic is dropped except 802.1X EAPoL packets. This is a
fundamental change from the traditional model in which the port is enabled and all traffic is allowed
from the moment that a device plugs into the port. Ports that were traditionally open will now be closed
by default. This is one of the cornerstones of the strong security and network access control provided by
802.1X. However, this change in the default network access model can have a profound impact on
network devices and applications. Understanding and providing for the impacts of this change will make
for a smooth deployment of 802.1X network access control.
Non-802.1X-Enabled Devices
802.1X must be enabled on both the host device and on the switch to which the device connects. If a
device without an 802.1X supplicant attempts to connect to a port that is enabled for 802.1X, it will be
subjected to the default security policy. The default security policy says that 802.1X authentication must
succeed before access to the network is granted. Therefore, by default, non-802.1X-capable devices
cannot get access to an 802.1X-protected network.
Although many devices increasingly support 802.1X, there will always be devices that require network
connectivity but do not and/or cannot support 802.1X. Examples of such devices include network
printers, badge readers, legacy servers, and PXE boot machines. Some provision must be made for these
devices.
Cisco provides two features to accommodate non-802.1X devices. These are MAC Authentication
Bypass (MAB) and the Guest VLAN. These features provide fallback mechanisms when there is no
802.1X supplicant. After 802.1X times out on a port, the port can move to an open state if MAB succeeds
or if the Guest VLAN is configured. Judicious application of either or both of these features will be
required for a successful 802.1X deployment.
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Note
Network-specific testing will be required to determine the optimal values for 802.1X timers to
accommodate the various non-802.1X-capable devices on your network.
802.1X in Schools
As mentioned above on the requirement for 802.1X authentication is the requirement for a supplicant.
This has typically been a challenge in the schools environment with a wide range of the devices and
limited or no management of many of these devices. In many schools this is still the case, and this makes
a district wide 802.1X very challenging. At the same time there are pockets of a school network where
802.1X may be a good choice.
For example 802.1X protected ports may be a good choice for the network ports in the District Office,
and the school administrator office, as these locations are more likely to have managed PCs.
Other locations in the schools network still need protection, but student network access may be better
served by a NAC Appliance solution. Network access ports in open areas such as classrooms may use
802.1X or Cisco Clean Access NAC to protect these ports.
When considering the 802.1X deployment, there are four main 802.1X authentication options to
consider.
•
Basic 802.1X Authentication—An 802.1X controlled port with an 802.1X client directly connected
•
IP Phone Ports—An IP Phone and an 802.1X controlled port with an 802.1X client connected to the
phone
•
MAC Auth By-Pass—Using the MAC address of the client to provide authentication and bypass the
802.1X authentication process. Printer and legacy device support are typical applications
•
Web Auth—Allowing a user to authenticate by entering username and passwords in a web page.
Legacy device support and guest access are typical deployment applications
Basic 802.1X Switch Configuration
The basic 802.1X configuration controls access to an access VLAN depending upon the success or
failure of the an 802.1X authentication. If the 802.1X authentication is successful, there are three basic
options:
•
Access to the VLAN configured on the switch port
•
Access to the VLAN configured on the switch port an controlled by a access list downloaded from
the AAA server
•
Access to a VLAN passed to the switch by the AAA server
Table 9-3 shows example 802.1X configurations.
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Table 9-3
802.1X Switch Configuration
Example 3750 802.1X PC Port Configuration
Example 3750 Global Configuration
authentication port-control auto
authentication periodic
dot1x pae authenticator
aaa new-model
aaa authentication dot1x default group radius
dot1x system-auth-control
ip radius source-interface Vlan300
radius-server host 10.40.62.9 auth-port 1812 acct-port 1813
key cisco
radius-server host 10.40.94.9 auth-port 1812 acct-port 1813
key cisco
For more information upon the 3750 802.1X configuration refer to the following documents:
Catalyst 3750-E and 3560-E Switch Software Configuration Guide, 12.2(50)SE ->Configuring IEEE
802.1x Port-Based Authentication
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750e_3560e/software/release/12.2_50_se/con
figuration/guide/sw8021x.html
Catalyst 2960 Switch Software Configuration Guide, Rel. 12.2(50)SE Configuring IEEE 802.1x
Port-Based Authentication
http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_50_se/configuratio
n/guide/sw8021x.html
NAC 802.1X and CISF in Combination
The three key access security features discussed above have been discussed in isolation, but can be
combined. In particular, the CISF features should be considered “baseline” features that are applied on
all access ports, and either NAC or 802.1X maybe overlaid on top of the CiSF configuration.
The Cisco Clean Access and 802.1X configuration are also compatible (although they are not often
combined in wired networks), the key consideration in combining the two is how to give the appearance
of a SSO for the end user. Both 802.1X and NAC require authentication, as 802.1X authenticates the
client initially, a mechanism of communicating the 802.1X authentication result to the Cisco Clean
Access system is required.
If the authenticating clients join an Windows Active Directory network, the Cisco Clean Access Active
Directory SSO feature allows the clients to authenticate to active directory once they have performed
there 802.1X authentication. The CAM, when a client is detected, checks Active Directory to see if the
client has authenticated; this allows a SSO experience for client devices that are using 802.1X and NAC.
DMP Ports
A DMP connection to the network is like that of a typical IP client. There should only be one MAC
address and one IP address on that port. This means that typical PC client port security settings will
work.
An DMP is primarily are receiver for packets, but if traffic classification from the DMP is important the
DSCP from the DMP should trusted
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Surveillance Camera Port
An the Surveillance Camera connection to the network is like that of a typical IP client. There should
only be one MAC address and one IP address on that port. This means that typical PC client port security
settings will work.
An the camera marks packets with DSCP marking based upon its configured QoS policies. Therefore,
to ensure that the QoS policy is effective the network must trust the DSCP Markings from the camera.
Power-over-Ethernet
The APs in the Schools SRA are 802.11n APs, and can provide greater than 100Mbps throughput, and
therefore they should use 1-Gigabit Ethernet.
An LWAPP AP connection to the network is like that of a typical IP client. There should only be one
MAC address and one IP address on that port. This means that typical PC client port security settings
will work. If 802.1X is used on the network the APs are able to act as 802.1X supplicants and
authenticate to the network. An LWAPP AP marks the LWAPP packets with DSCP marking based upon
the CUWN QoS policies. Therefore to ensure that the QoS policy is effective the network must trust the
DSCP Markings from the AP.
If the switch or module supports PoE, it may be able to power the APs connected to its ports.
Although the LWAPP APs can connect to the network in the same manner as a trusted PC client, it is
recommend that the LWAPP APs have their own dedicated subnet and VLAN. This makes AP specific
policies easier to implement within the network, and generally make network management tasks easier.
1250 Power-over-Ethernet
Today's PoE standard, 802.3af, peaks at getting 15.4 watts to the devices it powers. Unfortunately, 11n
requires a bit more power in order to realize the new standard's full potential. As a result, the Aironet
1250 Series access point requires 18.5 watts in full operational mode.*Note:*There is no getting around
the higher power requirements of 11n unless you either remove a radio (the Aironet 1250 Series access
point can run with a single radio on 802.3af) or remove valuable 11n functionality. Though others may
opt to do so, Cisco has chosen not to remove 11n's key features (such as spatial division multiplexing
support or multiple transmitters/receivers) in order to allow it to be powered with legacy PoE
infrastructure.How can you still use PoE functionality for a device that requires more wattage than the
current standard delivers? Midspan PoE, in which an injector powers the AP, is the simple answer. Just
make sure you purchase an injector that can support the additional power requirements. These can be
ordered along with the Aironet 1250 or separately; the midspan PoE injector part number is
AIR-PWRINJ4= and the AC adapter is AIR-PWR-SPLY1=). End-span PoE, in which the AP pulls
power from the switch to which it is connected, requires a bit more planning.In 2005, the IEEE came
together to address the issue of increasing power requirements and formed the 802.3at Working Group
to push through a higher power PoE standard. This new standard has yet to be ratified, which would
make it a full, industry-accepted protocol, but it does provide an archetype by which up to 30 watts may
be delivered to a device across existing Cat5 cabling. While 802.3at makes its way through the approval
process, Cisco provides an enhanced PoE (often called PoE Plus) option available in some of its flagship
switching products.Using Cisco Discover Protocol (CDP) and robust power subsystem engineering,
Cisco offers the Cisco Catalyst®3560E and 3750E with additional support (beyond the 802.3af
specification) for customers who wish to fully power a dual-radio Aironet 1250 Series access point.If
you decide that powering an Aironet 1250 Series access point via 802.2af is so important that you are
willing to forgo supporting either 2.4 GHz (11b/g/n) or 5 GHz (11a/n), you can use just one RF band. In
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such cases, plan to support a 2.4-GHz environment (due to the overwhelming majority of clients that
support this spectrum) and upgrade to support 5 GHz when budgetary, infrastructure, and user needs
align.
1140 Power-over-Ethernet (PoE)
The Cisco 1140 access point is 802.3af (15.4 W)-compliant and can be powered by any of the following
802.3af compliant devices: 2106 controller-WS-C3550, WS-C3560, and WS-C3750 switches-C1880
switch-2600, 2610, 2611, 2621, 2650, and 2651 multiservice platforms-2610XM, 2611XM, 2621XM,
2650XM, 2651XM, and 2691 multiservice platforms-2811, 2821, and 2851 integrated services
routers-3620, 3631-telco, 3640, and 3660 multiservice platforms-3725 and 3745 multiservice access
routers-3825 and 3845 integrated services routers-Any 802.3af compliant power injector.
Note
The Cisco 1140 Series access point requires a Gigabit Ethernet link to prevent the Ethernet port from
becoming a bottleneck for traffic because wireless traffic speeds exceed transmit speeds of a 10/100
Ethernet port.
Note
The Cisco 1250 Series access point can also be powered by a power injector (AIR-PWRINJ4) or local
power (AIR-PWR-SPLY).
IP Phones
The IP phones used in the Schools SRA are all able to use Power-over-Ethernet (PoE) and are able to be
powered by any of the PoE access switches discussed in this guide.
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10
School Site Design
The core/distribution component of the schools SRA is a key element in delivering a resilient network,
while providing a network configuration that is easy to manage and to deploy. This chapter discusses
both core/distribution models, the Cisco 3750 Stack model and the Cisco 4500 Modular switch model
.This chapter summarizes different connection types to the core/distribution models, and the key features
of those connections.
Large School—Modular Switch Design
The basic modular switch School topology is shown in Figure 10-1.This design is based upon a collapsed
core/distribution mode, and a Layer-2 access distribution model. In this type of design all of the IP
subnets are defined on the 4500 modular switch, and access to these subnets is controlled by the VLANs
that are trunked to the switches.
If desired a Layer-3 access switch model may be implemented, the physical topology does not change,
and centrality of EtherChannel to the design does not change. The simplicity of the network design not
only allows Layer-2 or Layer-3 access layers, it also allows a hybrid deployment. This allows the
majority of clients on the switch use Layer-3 access features, but a group of legacy client are able to
continue to use a Layer-2 network. This can be useful when migrating from clients that do not use IP, or
rely heavily upon locally broadcast information to learn about services or devices on the network.
The 4500 modular core provides resilient connections to the access LAN switches, local server switch,
WLC, and SRST Router through EtherChannel. The NAC Appliance does not support EtherChannel,
and the two connections are used to connect to the trusted and untrusted interfaces of the CAS.
The WAN connection to the 4500 modular is a single connection
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Figure 10-1
Stacked Switch School Schematic
WAN
CAS
SRST
V
WLC
Server
Switch
Access
Switch
Access
Switch
227525
PSTN
Core/Distribution Virtual Interfaces
The following is an example configuration of the switch virtual interfaces (SVIs) configured on the
core/distribution 4500 modular switch. This SVIs are trunked to the access switches as required, and
access to the VLANs are controlled by the switchport trunk allowed vlan command applied on the port
channels. The same basic configuration is used for the server switch.
interface Vlan101
description Connected to cr35_2960_Dept_1_VLAN
dampening
ip address 10.127.0.1 255.255.255.192
ip helper-address 10.125.31.2
no ip redirects
no ip unreachables
ip pim sparse-mode
load-interval 30
!
interface Vlan102
description Connected to cr35_2960_Dept_2_VLAN
dampening
ip address 10.127.0.65 255.255.255.192
ip helper-address 10.125.31.2
no ip redirects
no ip unreachables
ip pim sparse-mode
load-interval 30
!
...
!
interface Vlan110
description Connected to cr35_2960_Dept_10_VLAN
dampening
ip address 10.127.2.65 255.255.255.192
ip helper-address 10.125.31.2
no ip redirects
no ip unreachables
ip pim sparse-mode
load-interval 30
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Large School—Modular Switch Design
Example Port Channel Configuration
The following are examples of the port channel configuration on core/distribution 4500 modular switch
and an example access switch. A similar configuration would be applied to each access switch
connection with the same or different VLANs as required. From an IP routing or services level there is
no requirement to span the same VLAN to multiple switches, but if there is a requirement to support
legacy protocols such as AppleTalk at the school these AppleTalk VLANs can be easily spanned to
different access switches as required
Example 4500 Modular Switch Port Channel Configuration
interface Port-channel11
description Connected to cr35-2960-SS1
switchport
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110
switchport mode trunk
logging event link-status
load-interval 30
carrier-delay msec 0
qos trust dscp
Example 2960 Port Channel Configuration
interface Port-channel1
description Connected to cr35-4507-SS1
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,201
switchport mode trunk
ip arp inspection trust
load-interval 30
carrier-delay msec 0
hold-queue 2000 in
hold-queue 2000 out
ip dhcp snooping trust
WLC Connection
The WLC Connection to the core/distribution stack is fundamentally the same as an access switch
connection, with different VLANs, and the exception of using a different QoS trust mode, where the CoS
values from the WLC, are trusted. The following is an example 4500 modular switch Port Channel
configuration:
Interface Port-channel12
description Connected to WLC-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 111-120
switchport mode trunk
load-interval 30
carrier-delay msec 0
ip dhcp snooping trust
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NAC CAS Connection
The NAC CAS connection to the core/distribution switch. This is not an EtherChannel connection, but
two switch ports are consumed. The two ports consist of a untrusted port for connecting client VLANs
to the CAS prior to them completing the NAC process, and a trusted port that connects the NAS to the
client VLANs used once clients have successfully completed the NAC process. The two, trusted and
untrusted, ports are required even if OOB NAC is used, as the CAS requires access to the trusted VLANs
during the NAC process. The following is an example of the configuration.
Core/Distribution NAC CAS Configuration
interface GigabitEthernet1/0/4
description NAC Trusted Eth0
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 48,57,62
switchport mode trunk
spanning-tree portfast trunk
!
interface GigabitEthernet1/0/5
!
interface GigabitEthernet1/0/6
!
interface GigabitEthernet1/0/7
!
interface GigabitEthernet1/0/8
description NAC Untrusted Eth1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 61,248,257
switchport mode trunk
spanning-tree portfast trunk
SRST Connection Sample Configuration
The SRST connection to the core/distribution is another EtherChannel connection. The differences
between the SRST connection and the access switch connections are that a trunk connection is not
required, and that the SRST interfaces are router interfaces, requiring a slightly different connection.
The following is an example of the configuration.
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interface Port-channel3
description to isr for simulated PSTN GW for
school2
switchport access vlan 303
switchport mode access
interface GigabitEthernet2/0/20
switchport access vlan 303
switchport mode access
mls qos trust dscp
channel-group 3 mode on
end
interface GigabitEthernet3/0/20
switchport access vlan 303
switchport mode access
mls qos trust dscp
channel-group 3 mode on
end
interface Port-channel3
description port-channel to 4500
ip address 10.40.63.9 255.255.255.252
hold-queue 150 in
!
interface GigabitEthernet0/0
description $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-GE 0/0$
no ip address
duplex auto
speed auto
media-type rj45
no keepalive
channel-group 3
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
media-type rj45
no keepalive
channel-group 3
WAN Connection
The WAN connection is a single port connection from the core/distribution switch, and therefore there
is no EtherChannel. The key component in the WAN connection configuration is the QoS
implementation, that provides traffic shaping and limiting on this interface to ensure that the voice and
video are given appropriate priority, but do not starve other applications of the throughput. An example
of the WAN connection configuration is shown below.
WAN Port Sample Configuration—Core/Distribution
interface GigabitEthernet3/0/52
description Connected to MetroE-Core
switchport trunk encapsulation dot1q
switchport trunk native vlan 801
switchport trunk allowed vlan 650
switchport mode trunk
load-interval 30
carrier-delay msec 0
srr-queue bandwidth shape 35 15 25 25
srr-queue bandwidth limit 10
priority-queue out
mls qos trust dscp
no cdp enable
spanning-tree portfast trunk
spanning-tree bpdufilter enable
hold-queue 2000 in
hold-queue 2000 out
interface Vlan650
dampening
ip address 10.126.1.99 255.255.255.254
no ip redirects
no ip unreachables
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ip pim sparse-mode
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip summary-address eigrp 100 10.127.112.0 255.255.248.0 5
load-interval 30
hold-queue 2000 in
hold-queue 2000 out
Small School—Stacked Switch Design
The basic stacked switch school topology is shown in Figure 10-2.This design is based upon a collapsed
core/distribution mode, and a Layer-2 access distribution model. In this type of design, all of the IP
subnets are defined on the 3750 stacked switch, and access to these subnets is controlled by the VLANs
that are trunked to the switches.
The 3750 stackwise core provides resilient connections to the access LAN switches, local server switch,
WLC, and SRST router through EtherChannel. The NAC Appliance does not support EtherChannel, and
the two connections are used to connect to the trusted and untrusted interfaces of the CAS. The WAN
connection to the 3750 stack is a single Ethernet connection.
Figure 10-2
Stacked Switch School Schematic
WAN
CAS
SRST
V
WLC
Server
Switch
Access
Switch
Access
Switch
227526
PSTN
Below is an example configuration of the SVIs configured on the core/distribution 3750 stack. These
SVIs are trunked to the access switches as required, and access to the VLANs are controlled by the
switchport trunk allowed vlan command applied on the port channels. The same basic configuration
is used for the server switch.
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Core/Distribution Virtual Interfaces
Example Port Channel Configuration
The following example shows an example of the port channel configuration on core/distribution 3750
stack and an example access switch. A similar configuration would be applied to each access switch
connection with the same or different VLANs as required. From an IP routing or services level there is
no requirement to span the same VLAN to multiple switches, but if there is a requirement to support
legacy protocols such as AppleTalk at the school these AppleTalk VLANs can be easily spanned to
different access switches as required.
Example 3750 Stack Port Channel Configuration
Example 2960 Port Channel Configuration
Interface Port-channel11
description Connected to 2960-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,900
switchport mode trunk
load-interval 30
carrier-delay msec 0
ip dhcp snooping trust
Interface Port-channel1
description Connected to 3750-Core-SS2
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110
switchport mode trunk
ip arp inspection trust
load-interval 30
ip dhcp snooping trust
interface GigabitEthernet1/0/49
description Connected to 2960-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,900
switchport mode trunk
load-interval 30
carrier-delay msec 0
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
channel-group 11 mode active
spanning-tree guard root
ip dhcp snooping trust
!
interface GigabitEthernet3/0/49
description Connected to 2960-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,900
switchport mode trunk
load-interval 30
carrier-delay msec 0
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
channel-group 11 mode active
interface GigabitEthernet0/1
description Connected to 3750-Core-SS2
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110
switchport mode trunk
ip arp inspection trust
load-interval 30
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust dscp
channel-protocol lacp
channel-group 1 mode active
ip dhcp snooping trust
!
interface GigabitEthernet0/2
description Connected to 3750-Core-SS2
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110
switchport mode trunk
ip arp inspection trust
load-interval 30
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust dscp
channel-protocol lacp
channel-group 1 mode active
ip dhcp snooping trust
spanning-tree guard root
ip dhcp snooping trust
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Small School—Stacked Switch Design
WLC Connection
The WLC connection to the core/distribution stack is fundamentally the same as an access switch
connection, with different VLANs, and the exception of using a different QoS trust mode, where the CoS
values from the WLC, are trusted. The following is an example of the configuration.
Example 3750 Stack Port Channel Configuration
Interface Port-channel12
description Connected to 2960-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 111-120
switchport mode trunk
load-interval 30
carrier-delay msec 0
ip dhcp snooping trust
interface GigabitEthernet1/0/48
description Connected to WLC-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 110-120
switchport mode trunk
load-interval 30
carrier-delay msec 0
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust coschannel-group 11 mode active
spanning-tree guard root
!
interface GigabitEthernet3/0/48
description Connected to WLC-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 110-110,
switchport mode trunk
load-interval 30
carrier-delay msec 0
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust coschannel-group 11 mode active
spanning-tree guard root
NAC CAS Connection
The NAC CAS connection to the core/distribution switch. This is not an EtherChannel connection, but
two switch ports are consumed. The two ports consist of a untrusted port for connecting client VLANs
to the CAS prior to them completing the NAC process, and a trusted port that connects the NAS to the
client VLANs used once clients have successfully completed the NAC process. The two, trusted and
untrusted, ports are required even if OOB NAC is used, as the CAS requires access to the trusted VLANs
during the NAC process. The following is an example of the configuration.
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Core/Distribution NAC CAS Configuration
interface GigabitEthernet1/0/4
description NAC Trusted Eth0
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 48,57,62
switchport mode trunk
spanning-tree portfast trunk
!
interface GigabitEthernet1/0/5
!
interface GigabitEthernet1/0/8
description NAC Untrusted Eth1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 61,248,257
switchport mode trunk
spanning-tree portfast trunk
SRST Connection
The SRST connection to the core/distribution is another EtherChannel connection. The differences
between the SRST connection and the access switch connections are that a trunk connection is not
required, and that the SRST interfaces are router interfaces, requiring a slightly different connection.
The following is an example of the configuration.
interface Port-channel3
description to isr for simulated PSTN GW for
school1
switchport access vlan 303
switchport mode access
interface GigabitEthernet2/0/20
switchport access vlan 303
switchport mode access
mls qos trust dscp
channel-group 3 mode on
end
interface GigabitEthernet3/0/20
switchport access vlan 303
switchport mode access
mls qos trust dscp
channel-group 3 mode on
end
interface Port-channel3
description port-channel to core stack
ip address 10.40.63.9 255.255.255.252
hold-queue 150 in
!
interface GigabitEthernet0/0
description $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-GE 0/0$
no ip address
duplex auto
speed auto
media-type rj45
no keepalive
channel-group 3
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
media-type rj45
no keepalive
channel-group 3
WAN Connection
The WAN connection is a single port connection from the core/distribution switch, and therefore there
is no EtherChannel. The key component in the WAN connection configuration is the QoS
implementation, that provides traffic shaping and limiting on this interface to ensure that the Voice and
Video are given appropriate priority, but do not starve other applications of the throughput. An example
of the WAN connection configuration is shown below.
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interface GigabitEthernet3/0/52
description Connected to MetroE-Core
switchport trunk encapsulation dot1q
switchport trunk native vlan 801
switchport trunk allowed vlan 650
switchport mode trunk
load-interval 30
carrier-delay msec 0
srr-queue bandwidth shape 35 15 25 25
srr-queue bandwidth limit 10
priority-queue out
mls qos trust dscp
no cdp enable
spanning-tree portfast trunk
spanning-tree bpdufilter enable
hold-queue 2000 in
hold-queue 2000 out
interface Vlan650
dampening
ip address 10.126.1.99 255.255.255.254
no ip redirects
no ip unreachables
ip pim sparse-mode
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip summary-address eigrp 100 10.127.112.0 255.255.248.0 5
load-interval 30
hold-queue 2000 in
hold-queue 2000 out
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11
District Office Design
There are four main differences in the district office design:
•
The use of the Supervisor 6—The Supervisor 6 supports hierarchical QoS.
•
The Metro Ethernet Switch Connection—The aggregation and QoS policy enforcement point for the
Metro Ethernet WAN connection to the schools
•
The Services Block Switch Connection—The district office “mini-Data Center” for the management
and services servers for the district and the schools
•
The ASA Firewall Connection—The firewall connection to the Internet
Figure 11-1 shows a schematic of the district office network. Aside from providing core/distribution
services to the access switches, the Cisco 4500 Modular switch in the district office connects the school
WAN to the district office, the services such as Internet access and the Services Block of the SRA.
Figure 11-1
District Office Partial Schematic
WAN
ME
SRST
Metro
Ethernet
Switch
CAS
SRST
V
Internet
Access
Switch
Access
Switch
Services Block
Switch
227527
WLC
ASA
Firewall
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Metro Ethernet Connection Configuration
Metro Ethernet Connection Configuration
Table 11-1 shows an example of the port-channel configuration on the core/distribution 4500 Modular
switch and the 3750 Metro Ethernet switch. This is a Layer-3 connection where both the
core/distribution switch and the Metro Ethernet switch are part of the same EIGRP AS. The most
significant difference in this configuration from the School design using the 4500 Modular switch is the
difference in the QoS configuration on the 4500 interface; this is primarily due to the district office using
hierarchical QoS features of a Supervisor 6 module, rather than the Supervisor 5 used in the School SRA.
Table 11-1
Port-Channel Configuration on the Core/Distribution 4500 Modular Switch and the 3750 Metro Ethernet
Switch
Example 4500 Modular Switch Configuration
Example 3750ME Switch Configuraiton
interface Port-channel1
description Connected to 3750ME-DO
dampening
ip address 10.125.32.4 255.255.255.254
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip pim dr-priority 100
ip pim sparse-mode
ip summary-address eigrp 100 10.125.0.0 255.255.0.0
5
logging event link-status
load-interval 30
carrier-delay msec 0
service-policy output PQ-POLICER
interface Port-channel1
description Connected to 4507-DO
no switchport
dampening
ip address 10.125.32.5 255.255.255.254
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip pim sparse-mode
ip summary-address eigrp 100 10.127.0.0 255.255.0.0 5
ip summary-address eigrp 100 10.126.0.0 255.255.0.0 5
logging event bundle-status
load-interval 30
carrier-delay msec 0
hold-queue 2000 in
hold-queue 2000 out
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ASA Connection
Table 11-1
Port-Channel Configuration on the Core/Distribution 4500 Modular Switch and the 3750 Metro Ethernet
Switch (continued)
interface GigabitEthernet3/3
no switchport
no ip address
load-interval 30
carrier-delay msec 0
udld port
channel-protocol pagp
channel-group 1 mode desirable
service-policy output EGRESS-POLICY
!
interface GigabitEthernet4/3
no switchport
no ip address
load-interval 30
carrier-delay msec 0
udld port
channel-protocol pagp
channel-group 1 mode desirable
service-policy output EGRESS-POLICY
interface GigabitEthernet1/0/1
description Connected to cr24-4507-DO
no switchport
no ip address
logging event bundle-status
load-interval 30
carrier-delay msec 0
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust dscp
channel-protocol pagp
channel-group 1 mode desirable
!
interface GigabitEthernet1/0/2
description Connected to cr24-4507-DO
no switchport
no ip address
logging event bundle-status
load-interval 30
carrier-delay msec 0
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust dscp
channel-protocol pagp
channel-group 1 mode desirable
policy-map PQ-POLICER
class PRIORITY-QUEUE
police cir 300000000
conform-action transmit
exceed-action drop policy-map EGRESS-POLICY
class PRIORITY-QUEUE
priority
class CONTROL-MGMT-QUEUE
bandwidth remaining percent 10
class MULTIMEDIA-CONFERENCING-QUEUE
bandwidth remaining percent 10
class MULTIMEDIA-STREAMING-QUEUE
bandwidth remaining percent 10
class TRANSACTIONAL-DATA-QUEUE
bandwidth remaining percent 10
dbl
class BULK-DATA-QUEUE
bandwidth remaining percent 4
dbl
class SCAVENGER-QUEUE
bandwidth remaining percent 1
class class-default
bandwidth remaining percent 25
dbl
ASA Connection
The ASA firewall connection to the 4500 Modular switch is fundamentally different from the other
network device connections to this switch—it uses the redundant interface features of the ASA. The
ASA redundant interface is a logical interface that pairs two physical interfaces, called active and
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standby interfaces. Under normal operation, the active interface is the only one passing traffic. The
active interface uses the IP address defined at the redundant interface, and the MAC address of the first
physical interface associated with the redundant interface. When the active interface fails, the standby
interface becomes active and starts passing traffic. The same IP address and MAC address are
maintained so that traffic is not disrupted. See Table 11-2.
Table 11-2
ASA Connection Configuration
Example 4500 Modular Switch Configuration
Example ASA Interface Configuration
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Table 11-2
ASA Connection Configuration (continued)
interface GigabitEthernet4/4
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-->description backup link to cr26-asa5520-DO
switchport access vlan 200
switchport mode access
switchport block unicast
load-interval 30
spanning-tree portfast
spanning-tree bpduguard enable
service-policy output EGRESS-POLICY
!
interface GigabitEthernet5/3
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--> description Connected to cr26-asa5520-DO
switchport access vlan 200
switchport mode access
switchport block unicast
load-interval 30
media-type rj45
spanning-tree portfast
spanning-tree bpduguard enable
service-policy output EGRESS-POLICY
!
interface GigabitEthernet0/0
description Connected to cr24-4507-DO
no nameif
no security-level
no ip address
!
interface GigabitEthernet0/1
description backup to cr24-4507-DO
no nameif
no security-level
no ip address
!
! Defines logical redundant interface associated with
physical interfaces. Configures IP and logical interface
parameters.
interface Redundant1
description Connected to cr24-4507-DO
member-interface GigabitEthernet0/0
member-interface GigabitEthernet0/1
nameif inside
security-level 100
ip address 10.125.33.10 255.255.255.0
authentication key eigrp 100 <removed> key-id 1
authentication mode eigrp 100 md5
!
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Services Block Connection
Table 11-2
ASA Connection Configuration (continued)
interface Vlan200
description cr24_4507_FW_Inside
ip address 10.125.33.9 255.255.255.0
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100
eigrp-key
ip pim sparse-mode
ip summary-address eigrp 100 10.125.0.0
255.255.0.0 5
logging event link-status
load-interval 30
carrier-delay msec 0
Services Block Connection
The Services Block supports the centralized servers and services for the district. The Cisco 4500
Modular switch connection to the Services Block switch uses EtherChannel, but in this case the
connection between the switches is a Layer-3 connection, allowing the services block switch to keep its
VLANs from stack is fundamentally the same as an access switch connection, with different VLANs.
Table 11-3 provides sample configurations for the Cisco 4500 Modular switch and the Services Block
switch.
Table 11-3
Service Block Configuration
Example 4500 Modular Switch Configuration
Example Services Block Switch Configuration
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Services Block Connection
Table 11-3
Service Block Configuration
interface Port-channel17
description Connected to cr26-3750DC-DO
switchport
switchport trunk native vlan 806
switchport trunk allowed vlan 141-150,900
switchport mode trunk
logging event link-status
load-interval 30
carrier-delay msec 0
service-policy output PQ-POLICER
interface Port-channel1
description Connected to cr24-4507-DO
switchport trunk encapsulation dot1q
switchport trunk native vlan 806
switchport trunk allowed vlan 141-150,900
switchport mode trunk
logging event bundle-status
load-interval 30
carrier-delay msec 0
hold-queue 2000 in
hold-queue 2000 out
interface GigabitEthernet1/1
description Connected to cr24-2960-DO
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,900
switchport mode trunk
logging event link-status
load-interval 30
carrier-delay msec 0
udld port
channel-protocol pagp
channel-group 11 mode desirable
spanning-tree guard root
service-policy output EGRESS-POLICY
interface GigabitEthernet0/1
description Connected to cr24-4507-DO
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,201,900
switchport mode trunk
ip arp inspection trust
load-interval 30
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust dscp
channel-protocol pagp
channel-group 1 mode desirable
hold-queue 2000 in
hold-queue 2000 out
ip dhcp snooping trust
!
interface GigabitEthernet0/2
description Connected to cr24-4507-DO
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,201,900
switchport mode trunk
ip arp inspection trust
load-interval 30
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust dscp
channel-protocol pagp
channel-group 1 mode desirable
hold-queue 2000 in
hold-queue 2000 out
ip dhcp snooping trust
!
interface GigabitEthernet2/1
description Connected to cr24-2960-DO
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,900
switchport mode trunk
logging event link-status
load-interval 30
carrier-delay msec 0
udld port
channel-protocol pagp
channel-group 11 mode desirable
spanning-tree guard root
service-policy output EGRESS-POLICY
Core/Distribution Virtual Interfaces
The following is an example configuration of the Switch Virtual Interfaces configured on the
core/distribution 4500 modular switch. This SVIs are trunked to the access switches as required, and
access to the VLANs are controlled by the switchport trunk allowed vlan command applied on the port
channels. The same basic configuration is used for the Server Switch.
interface Vlan101
description Connected to cr24_2960_Dept_1_VLAN
dampening
ip address 10.125.1.1 255.255.255.128
ip helper-address 10.125.31.2
no ip redirects
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no ip unreachables
ip pim sparse-mode
load-interval 30
!
interface Vlan102
description Connected to cr24_2960_Dept_2_VLAN
dampening
ip address 10.125.1.129 255.255.255.128
ip helper-address 10.125.31.2
no ip redirects
no ip unreachables
ip pim sparse-mode
load-interval 30
!
...
interface Vlan110
description Connected to cr24_2960_Dept_10_VLAN
dampening
ip address 10.125.5.129 255.255.255.128
ip helper-address 10.125.31.2
no ip redirects
no ip unreachables
ip pim sparse-mode
load-interval 30
Table 11-4 provides examples of the port-channel configuration on core/distribution 4500 modular
switch and an access switch. A similar configuration would be applied to each access switch connection
with the same or different VLANs as required. From an IP routing or services level there is no
requirement to span the same VLAN to multiple switches, but if there is a requirement to support legacy
protocols such as AppleTalk at the school these AppleTalk VLANs can be easily spanned to different
access switches as required.
Table 11-4
Core/Distribution Virtual Interfaces
Example 4500 Modular switch Port Channel Configuration
Example 2960 Port Channel Configuration
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WLC Connection
Table 11-4
Core/Distribution Virtual Interfaces (continued)
interface Port-channel11
description Connected to cr24-2960-DO
switchport
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,900
switchport mode trunk
logging event link-status
load-interval 30
carrier-delay msec 0
service-policy output PQ-POLICER
interface Port-channel1
description Connected to cr24-4507-DO
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,201,900
switchport mode trunk
ip arp inspection trust
load-interval 30
carrier-delay msec 0
hold-queue 2000 in
hold-queue 2000 out
ip dhcp snooping trust
interface GigabitEthernet1/1
description Connected to cr24-2960-DO
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,900
switchport mode trunk
logging event link-status
load-interval 30
carrier-delay msec 0
udld port
channel-protocol pagp
channel-group 11 mode desirable
spanning-tree guard root
service-policy output EGRESS-POLICY
interface GigabitEthernet0/1
description Connected to cr24-4507-DO
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,201,900
switchport mode trunk
ip arp inspection trust
load-interval 30
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust dscp
channel-protocol pagp
channel-group 1 mode desirable
hold-queue 2000 in
hold-queue 2000 out
ip dhcp snooping trust
!
interface GigabitEthernet0/2
description Connected to cr24-4507-DO
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,201,900
switchport mode trunk
ip arp inspection trust
load-interval 30
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust dscp
channel-protocol pagp
channel-group 1 mode desirable
hold-queue 2000 in
hold-queue 2000 out
ip dhcp snooping trust
interface GigabitEthernet2/1
description Connected to cr24-2960-DO
switchport trunk native vlan 802
switchport trunk allowed vlan 101-110,900
switchport mode trunk
logging event link-status
load-interval 30
carrier-delay msec 0
udld port
channel-protocol pagp
channel-group 11 mode desirable
spanning-tree guard root
service-policy output EGRESS-POLICY
WLC Connection
The WLC Connection to the Core/Distribution Stack is fundamentally the same as an Access Switch
connection, with different VLANs, and the exception of using a different QoS trust mode, where the CoS
values from the WLC, are trusted. Figure 7 shows an example of the configuration.
Interface Port-channel12
description Connected to WLC-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 111-120
switchport mode trunk
load-interval 30
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carrier-delay msec 0
ip dhcp snooping trust
interface GigabitEthernet1/0/48
description Connected to WLC-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 110-120
switchport mode trunk
load-interval 30
carrier-delay msec 0
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust cos
channel-group 11 mode active
spanning-tree guard root
!
interface GigabitEthernet3/0/48
description Connected to WLC-SS2
switchport trunk encapsulation dot1q
switchport trunk native vlan 802
switchport trunk allowed vlan 110-110,
switchport mode trunk
load-interval 30
carrier-delay msec 0
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust cos
channel-group 11 mode active
spanning-tree guard root
NAC CAS Connection
The NAC CAS connection to the core/distribution switch. This is not an EtherChannel connection, but
two switch ports are consumed. The two ports consist of a untrusted port for connecting client VLANs
to the CAS prior to them completing the NAC process, and a trusted port that connects the NAS to the
client VLANs used once clients have successfully completed the NAC process. The two, trusted and
untrusted, ports are required even if OOB NAC is used, as the CAS requires access to the trusted VLANs
during the NAC process. The following is an example of the configuration.
interface GigabitEthernet 3/9
description NAC Trusted Eth0
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 48,57,62
switchport mode trunk
spanning-tree portfast trunk
!
interface GigabitEthernet 4/9
description NAC Untrusted Eth1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 61,248,257
switchport mode trunk
spanning-tree portfast trunk
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SRST Connection
SRST Connection
The SRST connection to the core/distribution is another EtherChannel connection. The differences
between the SRST connection and the access switch connections are that a trunk connection is not
required, and that the SRST interfaces are router interfaces, requiring a slightly different connection.
Table 11-5 provides an example of the configuration.
Table 11-5
SRST Connection
Core/Distribution
ISR Routers
interface Port-channel1
description Connected to ISR
dampening
ip address 10.125.32.4 255.255.255.254
ip authentication mode eigrp 100 md5
ip authentication key-chain eigrp 100 eigrp-key
ip pim dr-priority 100
ip pim sparse-mode
logging event link-status
load-interval 30
carrier-delay msec 0
service-policy output PQ-POLICER
!
interface GigabitEthernet3/10
no switchport
no ip address
load-interval 30
carrier-delay msec 0
udld port
channel-protocol pagp
channel-group 1 mode desirable
service-policy output EGRESS-POLICY
!
interface GigabitEthernet4/10
no switchport
no ip address
load-interval 30
carrier-delay msec 0
udld port
channel-protocol pagp
channel-group 1 mode desirable
service-policy output EGRESS-POLICY
interface Port-channel3
description port-channel to 4500
ip address 10.125.32.3 255.255.255.254
hold-queue 150 in
Note: Need to add the routing information
!
interface GigabitEthernet0/0
description $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-GE 0/0$
no ip address
duplex auto
speed auto
media-type rj45
no keepalive
channel-group 3
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
media-type rj45
no keepalive
channel-group 3
NTP
The use of Network Time Protocol (NTP) to synchronize the clocks of network devices is a well
established best practice, is fundamental for the analysis of logs/events and security, but might not
warrant a mention in a design guide that is focused upon introducing new designs and practices to
support new services in the network.
Given that a number of key components (for example, CUWN and Cisco NAC) of the Schools SRA rely
upon or benefit from time synchronization, it was decided to include a short discussion on Time
Synchronization as part of the Schools SRA.
The preferred mechanism for time synchronization in the network is NTP (other systems may use their
own time synchronization mechanism) and this network NTP discussion is not proposed as a the design
to synchronize all devices (hosts) in the network, its goal is synchronization of the network components
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NTP
of the Schools SRA. At the same time, whatever alternative times synchronization systems used in other
parts of the network need to have agreement on the time, and should have a common time source at the
beginning of their timing hierarchy. This will allow sufficient synchronization between hosts and
network devices for the solutions deployed in the SRA.
The Schools SRA network has a hierarchy based upon the district office, as hub, and the schools as
spokes. The NTP hierarchy should be the same, with the highest stratum NTP server located at the
district office serving as the time reference for the district network. In order to spread the load, a
hierarchy of NTP servers is used. The district office NTP server acting as the server for the district office
network devices, and for the NTP server at each school, and the NTP Server for each school will act as
the NTP server for network devices in that school.
The preferred network device to act as the NTP server in the schools SRA is the ISR router at each site.
The ISR is the preferred device as routers have a greater CPU capacity than switches used in the Schools
SRA due to many of the general purpose task that a router may be required it perform in CPU, compared
to switches that have been more optimized to perform their more limited number of tasks in ASIC.
Figure 11-2 shows a schematic of the NTP hierarchy in the school district.
For more information upon NTP refer to the Network Time Protocol: Best Practices White Paper at the
following URL:
http://www.cisco.com/en/US/tech/tk869/tk769/technologies_white_paper09186a0080117070.shtml
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Figure 11-2
NTP School District Hierarchy
CAS
School 1
NTP
V
WLC
SRST
District Office
ME
Metro
Ethernet
Switch
NTP
Server
Switch
Access
Switch
CAS
Access
Switch
V
SRST
MAN
Internet
ASA
Firewall
Distribution
Switch
Access
Switch
Access
Switch
WLC
School 2
CAS
NTP
Services Block
Switch
V
WLC
SRST
Access
Switch
Access
Switch
227528
Server
Switch
When creating the NTP configuration care should be taken to protect the NTP system.
The NTP associations should be limited, and controlled by an access list, to protect against DoS attacks.
The NTP system should also use NTP authentication, where possible, to protected against spoofing
attacks.
DO-ISR NTP
School1-ISR
access-list 99 permit x.x.x.x 0.0.0.255
access-list 99 permit y.y.y.y 0.0.0.255
ntp authentication-key 2 md5 Riewoldt
ntp authenticate
ntp source Port-channel3
ntp max-associations 150
ntp server a.a.a.a
ntp access-group serve-only 99
access-list 98 permit z.z.z.z 0.0.0.255
ntp authentication-key 2 md5 Riewoldt
ntp trusted-key 2
ntp clock-period 17179685
ntp max-associations 150
ntp server <DO-ISR> key 2
ntp access-group serve-only 98
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Cisco Validated Design
Cisco’s Service Ready Architecture for Schools
is a well designed and validated network architecture that is flexible, adaptive and cost effec-
dent chapters as shown in Table1-1 on page 2.
.
tive to support a wide range of education
services. This architecture provides the ability
to deliver all of the services required of an
enhanced learning environment as well as the
ability to collaborate with the other schools, district offices and entities beyond the district. This
Service Ready Architecture for Schools Design
Guide is broken down into modular, interdepen-
www.cisco.com/go/designzone
Copyright © 2009 Cisco Systems, Inc. All rights reserved.
Part Number
Cisco Validated Design
Book Spine
Service Ready Architecture for Schools Design Guide
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