spscom.com
SIP and VoIP Fundamentals
Mike Taylor - CTO
Strategic Products and Services
888.777.7280
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300 Littleton Road
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Parsippany, NJ 07054
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What is SIP?
Acceptance of SIP
SIP Economics?
Leveraging SIP for Mobility
SIP and Business Continuity
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Text Based Signaling Protocol –
IETF 3261
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Think HTTP
Signaling for Voice, Video, IM/Chat or ….
Separate from Media
SS7
Media
ISDN SIP
The more it changes the more it stays the same!
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SIP is the “language” that devices speak to set up phone calls (or other types of communications) between devices.
After the call is set up, the device uses Real
Time Protocol (RTP) for the talk path (just like H.323)
SIP uses English (people can read it) messages to communicate between endpoints.
This is good and bad. Security concerns.
SIP is not proprietary – it is developed as an industry standard protocol!
SIP vs. H.323
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Both of these protocols are IEEE industry standard signaling protocols
They are not proprietary
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H.323
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Mature protocol that can support a large set of call control features
SIP
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Is maturing and call control features are currently being added
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Does not yet support the full set of call control features as is in H.323 today
Has the promise of much more because this protocol has the potential to do much more
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SIP vs. H.323
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These are simply signaling protocols with
IEEE RFC documents that describe the details of the protocol spec
The specific method of SIP implementation is up to the provider of the product being used
In general, each SIP implementation will be a little different
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Most SIP termination devices will have
“Adaption Modules” to account for these differences
H.323 is a more mature protocol where most of the interoperability issues have been resolved
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SIP is being adopted by EVERYONE as the industry standard signaling protocol.
This includes Avaya, Microsoft, Cisco,
WorldCom, AT&T, CommWorks, Google,
Lucent and Yahoo!
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User Agents
Network Servers
SIP Messages
Session Description Protocol
Gateways and SBCs
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SIP
Components
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User Agent Client
(UAC) : It generates requests and send the request to servers - typically Proxies or Registrars
User Agent Server
(UAS) : It gets requests, processes those requests and generate responses.
Back-To-Back User Agent
(B2BUA) : Both
UAC and UAS
A UA can be either a UAS or UAC dependent on which UA initiated the request for the media session. It is also possible that a UA could be operating as both a UAS and UAC especially during a three-way call or call transfer.
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SIP User
Agents
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User agents (UAs) are applications installed on SIP endpoints such as an IP phone, mobile phone, wireless device , or a laptop / desktop PC that interface between the user and the SIP network.
SIP UAC/UAS
SIP UAC/UAS
SIP Network
Servers
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Network servers provide:
Registrar and Location services
Routing (Proxy or Redirect)
Presences Services
Servers in the network allow easy session establishment!
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SIP Network Server
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REGISTER
INFO
SIP Method
SIP Messages
Simple Yet
Powerful
SIP Method
INVITE
Description
Invites a user to a call
ACK
BYE
Used to facilitate reliable message exchange for
INVITEs
Terminates a connection between users or declines a call
CANCEL
OPTIONS
Terminates a request, or search, for a user
Solicits information about a server's capabilities
Registers a user's current location
Used for mid-session signaling
Description
SIP UAC/UAS
SIP
Network
Server
SIP UAC/UAS
Session
Description
Protocol
(SDP)
SDP is used for
multimedia
session announcement, invitation and other forms session initiation
SDP determines following additional information:
Bandwidth
Contact info for the person responsible for the media type
Transport protocol
Media format
Multicast address and Transport Port for media.
Remote address for media / Transport port for contact address.
Once the SIP session is built, SDP adds multimedia
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Gateways and
Session Border
Controllers
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SIP Gateways
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Provide protocol translation and interoperability with non-SIP system elements such as:
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TDM
H.323, and
PSTN
Session Border Controllers (SBCs)
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Provide robust security and management by:
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Allowing SIP communications to transition enterprise firewalls
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Solving NAT traversal issues
As firewalls, preventing unauthorized access to and from an enterprise network.
A Single Pipe to the Cloud
Phones
Phones
LAN
LAN
PBX
Router
IP Data/Telephony
Internal Communications
PBX
TDM
External Communications
TDM
External Communications
Router
IP Data/Telephony
All Communications
PSTN Long
Distance
PSTN Local
Access
• VoIP for internal communications only
• Separate TDM interfaces required for external communications with partners/suppliers/customers
• Extra cost, extra hardware, extra complexity
IP
Network
VoIP Today
SIP Trunking
PSTN Long
Distance
Service
Provider
SIP
Network
• Single IP link for voice/data
• Eliminate PSTN interfaces for longdistance and local access
• Save 20%+ on toll charges
• Prepare for future SIP solutions
PSTN Local
Access
SIP
An ecosystem that broadens your app universe!
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Adaptable
For different users, needs,
• industries
Simple to use and deploy
Contextual
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How and where you work
Business process integration
Inclusive Architecture
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Leverage “best in class” apps from across solution providers
Multi-Modal
Speech, mobile devices, PCs, phones
Video, Web 2.0, collaboration, kiosks
SIP Disaggregates Voice Networks
Runs on TCP, UDP or SCT protocols
More cost effective that IP
Can carry rich UC to interconnect applications more effectively
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Worldwide SIP Trunking Line Penetration, 2008-2015:
Comparison of May 2008 and December 2009 Forecast
Line Centric
Voice Calls
Administered
Individual Routing
2008 2009 2010 2011 2012 2013 2014 2015
December 2009 Forecast
May 2008 Forecast
Source: IDC
User Centric
Multimedia Sessions
User Control
Centralized Policy
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Better Manageability
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SIP is easy to learn, develop, troubleshoot and support
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Modeled after HTTP, easier to understand and interpret
Single network for all communications
Enhanced scalability
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From single road warrior to small branch to carrierclass enterprise solutions with common applications and user experience
Lower Communications and Business Costs
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Cost saving SIP trunking
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Reduced PBX hardware
Minimize travel with collaborative applications
Leverage multimodal communications to eliminate the costs of delayed decision making
Reduce cost of real estate and optimize geographic coverage with a more mobile workforce
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BEFORE
PRI-based Architecture:
Capacity managed site-by site
Each site requires sufficient headroom
Small sites have dramatic under-utilization
AFTER
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SIP-based Architecture:
Underutilized PRIs from multiple vendors are collapsed onto a single handoff using a shared pool of concurrent call paths
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Example: 1,250 Seat Organization
5:1 User-to-SIP Trunk drives 250 sessions
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(11) T1 equivalent
$4,050 savings per month
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$57.60 per channel month for PRI
$41.40 per channel month for SIP
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$16.2 savings per month x 300 channels
Gartner report: http://www.gartner.com/id=1378124
250 Session Mediant 4000
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MSRP at $19,750
Reduce
HARDWARE components
Reduce
FOOTPRINT requirements
Reduce
POWER consumption
And this is not even using a high density gateway!
Before
8 full racks of equipment…
After
3 racks of equipment
Think of the hardware savings
…energy savings
…space savings
…power savings
…maintenance contracts
…T1 management reduction
Location A
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SIP traffic is data and can be re-routed. This includes DID numbers!
Do not necessarily have double the trunks to provide a 100% back up, just the access pipe
Carrier
Location B
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Native Mobility
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A single SIP Address Of Record (AOR) provides a unifying public address for all communications
SIP intelligence allows simultaneous or sequential “ringing” to all devices
End-point Flexibility
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Seamless integration of desk phones, video devices, soft clients or mobile phones and devices
Eliminate the complexity of multiple networks
Simplify business processes
Unprecedented Interoperability
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Open, IETF Standard based
Active working groups (SIPit, SIPconnect, SIP Forum)
Wide applications eco-system
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Presence
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Understand availability and communication preferences before initiating communications
Enhanced Constituent Service
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Speed first call resolution in the contact center through ability to leverage available experts and use side-bar communication channels
Faster decision making improves responsiveness to customers
Improved ability to reach the right employee drives customer satisfaction
Improved Employee Productivity
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Integrate communications into business processes
Maximize workforce effectiveness regardless of location
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Enterprise
Session Border
Controller
Enterprise
Session Manager
Active
Enterprise
IP-PBX Core
Carrier
SIP
SBC
Enterprise
Session Border
Controller
Enterprise
Session Manager
Active
Enterprise
IP-PBX Backup
Remote Worker
Or
Mobile Device
Session Border Controller
Security
SIP Normalization
Demarcation
Session Manager
SIP Registrar
Session Management
Application Integration
Dial Plan
Routing
Avaya AuraTM Savings
Estimator
Sales Engineering
Solution Architecture
Services
Financial Monitoring
Services
SIP Economic
Assessment Service
Business & Technical
Planning Services
Implementation
Services
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Current State Discovery &
Analysis
Current State Discovery &
Analysis
Example Deliverable:
IT Network Diagram
You can easily find anything in your IT Infrastructure with complete Drill-Down Details
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Optimize payback by using SIP in 2 ways:
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Internal SIP (Migrating Voice traffic to the Data Network)
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External SIP (Connectivity to the PSTN)
All options yield a positive return but a combined view accelerates the return in less than 2 years
spscom.com
Strategic Products and Services
888.777.7280
/
300 Littleton Road
/
Parsippany, NJ 07054
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