Spring Semester 2016 Seminar Software-Defined Wireless Networking Zhongliang Zhao Universität Bern 07.03.2016 Outline • Motivation • Software-Defined Networking & OpenFlow • Software-Defined Wireless Networking & OpenFlow Extension • SwissSenseSynergy Project Use Cases • Conclusions 2 Wireless Mobile Data Growth 3 Software-Defined Networking (SDN) • Decouple forwarding hardware / control decisions • Network devices are functionally broken up into • Software-based controllers (control plane) • Packet forwarding devices (data plane) • Attracting attention from academia and industry • Open Networking Foundation (ONF) • Network function virtualized on commodity hardware • Reducing CapEx (e.g., S/P-GW millions of $ per box) • Standardization efforts on SDN 4 SDN: Decoupled Control “A Survey of Software-Defined Networking: Past, Present, and Future of Programmable Networks (Fig 1)” 5 SDN Reference Architecture 6 SDN Application Environments Scenarios Use cases Datacenter Virtualization, multi-tenancy, failure recovery, traffic engineering, load-balancing Backbone Resiliency, reliability, determinism, traffic engineering and load-balancing Campus network Network access control, guest access, monitoring malicious behavior Security Firewalls, intrusion detection and prevention, blacklists, enforced quarantine Wireless Mobile wireless backhaul, heterogeneous wireless access, service chaining, load balanced packet core. 7 OpenFlow “A Survey of Software-Defined Networking: Past, Present, and Future of Programmable Networks (Fig 2)” 8 OpenFlow Controller • A network “operating system” • Programmatic interface to the network • Southbound communication standardized through the OpenFlow protocol • Northbound communication: no standard defined between controllers and applications (software implementation) “A Survey of Software-Defined Networking: Past, Present, and Future of Programmable Networks (Fig 3)” 9 Flow Table 10 OpenFlow Switch Packet Handling: <Match, Action> • Match • Match on any header • Action • Forward to ports, drop packet, send to controller • Overwrite header with mask, push or pop into waiting queue • Forward at specific bit-rate • Allows multiple actions 11 Flow Table Entries • Exact rules • All fields are specified • Higher priority than wildcard rules Ingress port Eth dst Eth src Eth type … Statistic action 5 00:12… 00:07… 0x0800 … counters Act 0 • Wildcard rules • At least one field contains a wildcard or a prefix • Multiple rules can match a packet à priorities Ingress port Eth dst Eth src Eth type … Statistic action * 00:23… * * … counters Act 0 12 OpenFlow Key Message and Types Message Direction Description Packet-in Switch à Controller Transfer the control of a packet to the Controller that does not match. Packet-in events can be configured to buffer packets Packet-out Controller à Switch Instruct switch to send a packet out of a specified port. Sent in response to Packet-in messages to manage flow entries Modify-state Controller à Switch Add, delete and modify flow/group entries in the flow tables (aka Flow-mod); set switch port properties Flow-removed Switch à Controller Inform the controller about the removal of a flow entry from a flow table 13 Open Networking Foundation (ONF) Wireless Mobile WG (WMWG) • Goal: identify OpenFlow enhancement to improve operations of wireless networks • WMWG use-cases and use-case project teams 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. Flexible scalable packet core Dynamic resource management for wireless backhaul Mobile Traffic Management Connection-Oriented SDN for Wireless SCB Management of secured flows in LTE Media-Independent Handover SDN Enhanced Distributed P/S-GW Network-Aware UE Multiple Radio Interface Management S-GW virtualization Service Chaining in Mobile Service Domain Energy Efficiency in Mobile Backhaul Network Security and Backhaul Optimization Unified Equipment Management and Control Network Based Mobility Management SDN-Based Mobility Management in LTE IEEE OmniRAN Unified Access Network for Enterprise and Large Campus Use Case Project Teams 1. Mobile Packet Core 2. Wireless Transport 3. Unified Access 14 WMWG Projects Mobile Packet Core Wireless Backhaul Unified Access —Apply OpenFlow to 3GPP Evolved Packet Core (EPC) —Many uses such as user/data plane separation in GW, mobility management and mobile flow steering for offload. —Backhaul links are wireless —Central SDN controller optimizes radio parameters in data plane using enhanced OpenFlow —Develop a unified access network that uses a common controller to manage both wireless access points (AP) and wired switches 15 Mobile Packet Core Project HSS MME S1-MME PCRF GW-C OF Controller Etc… 1. 2. OF-‐Switch+/OF-‐config+ eNodeB SGi Backhaul AP Operator’s IP Service 3. Address Three Use Cases SDN based Evolved Packet Core SDN based Mobility Management Service Chaining in Mobile Service Domain S1-U S2a/b/c SGi Internet Home eNB • • • EPC control plane and SDN controller separated from data plane implemented by enhanced OpenFlow switches Place and move the routing of GTP and non-GTP tunnel flows through EPC data plane using OpenFlow while supporting the needs of the wireless network OpenFlow extensions needed to support: • GTP/non-GTP tunneling, Policy Control, and Lawful Interception 16 Wireless Backhaul Project Application —Application plane — Client SDN Controller —Virtual Control 1. —Virtual Control —Microwave Backhaul SDN Controller —Optical Backhaul SDN Controller 2. 3. —Control plane —Direct Control —MW Backhaul Network —Direct Control —ETH Backhaul Network —Direct Control 4. Combining 4 Use Cases Backhaul resource management Energy Efficiency Unified Equipment Management Common Public Radio Interface (CPRI) and Ethernet support —Optical Backhaul Network —Data plane • Central SDN controller calculates the path and assigns the backhaul resources considering: • • • • SLA parameters (e.g., guaranteed vs. non-guaranteed) Link availability, capacity, e.g., adjusting modulation. Collection of traffic statistics to estimate the actual throughput Define new OpenFlow port types for wireless backhaul links (e.g. microwave) Unified Access Project AAA Server Wireless User SDN Applications Device/users Access 802.1X information Device Mgmt authenticator collector CAPWAP Policy rules Fast Secure Handoff 802.11r Rogue detection, etc… Unified Access NBI Convergence and Services Wired User VPN SDN Controller Remote User • • Controller leverages enhanced OpenFlow to manage both wired and wireless AP An unified architecture and consistent means of managing • • • User role/location based policy Real-time monitoring Need to support strong authentication of endpoints, fast roaming Software-Defined Wireless Networking • Wireless networks are more complex then Ethernet • • • • • Increasing amount of UE Mobility Unicast, multicast, broadcast Various QoS policy requirements Wireless radio interfaces have huge variety of properties • Radio properties (channel, tx power, RSSI levels) • TX characteristics (antenna features) • MAC layer issues (group-cast, broadcast) • SDN-based wireless networking requirements: • Provide control interface to query wireless network about availability, quality, speed, user location … • Control granularly how individual user or application traffic is handed by the network 19 OpenFlow Extension for Wireless • OF was originally designed for wired networks • It assumes that underlying network is composed of highspeed Ethernet switch/IP routers • Currently no support for the matching of 802.11 specific fields • Latest OpenFlow specification (v1.5) defines three types of port properties • Ethernet • Optical • Experimental • OF wireless extension is essential • Support for wireless port properties • Specific counters for wireless devices 20 Match/Action: Wired OpenFlow • “If a packet comes from port X, then apply VLAN Y, and forward through port Z” • Match fields defined for fields of Ethernet frame, IPv4/IPv6 packet, TCP segment, MPLS… • Not consider IEEE 802.11 or eNB specific frame format • Action fields defined • • • • Forward packet to physical port Enqueue packet to queue in the port Drop packet Modify field • Statistic fields defined per table, flow, port, queue 21 Match/Action: Wireless OpenFlow • “If a packet is for user M, with QoS requirement N, then apply encoding mechanism X, and transmit through port Y in rate Z and power-level B” • Match fields identify flows (wireless_flow_id) of individual users (ue_id) and/or application requirements • Action fields control how packets should be routed • • • • in which rate and power level using which encoding mechanism via which access point how they are scheduled at access points • How to define/label a wireless flow? • Radio technique dependent 22 Hierarchical Controller • Local agent (LA) at each base station or access point • Measure local network traffic, subscriber usage statistics, assess QoS policies, etc. • Perform local management tasks under the supervision of the central controller • Notify central controller if the traffic exceeds a certain threshold, tag some packets to be redirected to a transcoder, etc. • Central controller (CC) • Delegate some local controller function to LA • Management overall network status • Intelligent resource management 23 Hierarchical Controller (cont.) Central Controller Local agent Periodic Updates Controller API • • • Bytes Rate Queue Size Interference — (cont.)Flow Map Records Network Operator Inputs QoS Constraints Information Base Radio Element API RADIO ELEMENTS Intelligent Resource Management Algorithm 24 Hierarchical Controller: Message Updates • Local agent à Controller • Flow information (downlink/uplink) • Channel states (reported by clients to agent) • Link statistics (monitored by agent) • Network operator à Controller • QoS requirements • Flow preferences • Reactive: delay • Proactive: periodic update, which frequency? 25 Controller and Switch Support • OpenFlow Controller • NOX (C++/Python) • Floodlight (Java) • OpenDaylight (Java) • OpenFlow Switch • Commercial Switch • Software Switch • Open vSwitch • OpenWRT • Mininet • CPqD 26 SwissSenseSynergy Interests using SDN in Wireless Access • Traffic steering / radio planning • OpenFlow extension for WiFi port properties • Steering traffic based on statistics • Privacy-preserving location-based access control • OpenFlow message extension for privacy-related content 27 Traffic Steering / Radio Planning Unified Network Access Control Wireless User Enhanced OpenFlow OpenFlow Controller Traffic Generator Local Agent (LA) Central Controller (CC) • OF Action extension of real-time functions (rate-adaption) • OF Match support (message extension) for WiFi port properties and 802.11 frames • OF-Config support for deploying WiFi configurations • Traffic steering based on monitored statistics and resource utilization • Handover 28 Privacy-preserving Location-based Access Control Unified Access Device Mgmt Unified Network Access Control OpenFlow AAA Application RADIUS (UDP 1812/1813) Radius Server OpenFlow Controller Local Agent • • • • Central Controller (CC) OF Match support (message extension) for location-awareness OF Match support (message extension) for key-distribution OF captures/intercepts 802.1X messages AAA application on OF controller performs 802.1X AAA functions 29 Conclusions • • • • SDN & OpenFlow SDO activities OpenFlow extension for wireless networks SSS use-cases • Traffic steering • OpenFlow extension for WiFi ports • Traffic steering using collected statistics • Access control • OpenFlow extension for location-awareness and privacy mechanisms • Mininet + Floodlight + Open vSwitch (or OpenWRT) 30
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