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Software Defined Networking COMS 6998-8, Fall 2013

Software Defined Networking COMS 6998-8, Fall 2013. Instructor: Li Erran Li ( lierranli@cs.columbia.edu ) http://www.cs.columbia.edu/~lierranli/coms6998-8SDNFall2013 / 11/19 /2013: SDN Wireless Networks. Outline. Review Midterm SDN and Middleboxes SDN Wireless Networks Motivation

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Software Defined Networking COMS 6998-8, Fall 2013

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  1. Software Defined NetworkingCOMS 6998-8, Fall 2013 Instructor: Li Erran Li (lierranli@cs.columbia.edu) http://www.cs.columbia.edu/~lierranli/coms6998-8SDNFall2013/ 11/19/2013: SDN Wireless Networks

  2. Outline • Review • Midterm • SDN and Middleboxes • SDN Wireless Networks • Motivation • Data Plane Abstraction: OpenRadio • Control Plane Architecture • Radio Access Networks: SoftRAN • Core Networks: SoftCell Software Defined Networking (COMS 6998-8)

  3. Review of Previous Lecture: Middlebox Basics • A middlebox is any traffic processing device except for routers and switches. • Why do we need them? • Security • Performance • Functionality (e.g. echo cancellation, video transcoding) • Deployments of middlebox functionalities: • Embedded in switches and routers (e.g., packet filtering) • Specialized devices with hardware support of SSL acceleration, DPI, etc. • Virtual vs. Physical Appliances • Local (i.e., in-site) vs. Remote (i.e., in-the-cloud) deployments • They can break end-to-end semantics (e.g., load balancing) Software Defined Networking (COMS 6998-8)

  4. Review of Previous Lecture: Middlebox Consolidation VPN Web Mail IDS Proxy Firewall Protocol Parsers Session Management Contribution of reusable modules: 30 – 80 % Software Defined Networking (COMS 6998-8)

  5. Input ( Flows ) Output Review of Previous Lecture: Middlebox State Middlebox VM Caches Other processes ... Internal to a replica (ephemeral) May be shared among replicas (coherent) Threshold counters Non-critical statistics Application Logic Flow Table Partitionable among replicas Software Defined Networking (COMS 6998-8)

  6. Outline • Review • Midterm • SDN and Middleboxes • SDN Wireless Networks • Motivation • Data Plane Abstraction: OpenRadio • Control Plane Architecture • Radio Access Networks: SoftRAN • Core Networks: SoftCell Software Defined Networking (COMS 6998-8)

  7. Wireless Data Growth Question: How to substantially improve wireless capacity? Source: CISCO Visual Networking Index (VNI) Global Mobil Data Traffic Forecast 2011 to 2016 • AT&T • Wireless data growth 20,000% in the past 5 years Software Defined Networking (COMS 6998-8)

  8. OpenRadio: Access Dataplane • Forwarding • Dataplane • Control • CPU • Baseband & • Layer 2 DSP • Exposes a match/action interface to program how a flow is forwarded, scheduled & encoded • RF • RF • RF OpenRadio APs built with merchant DSP & ARM silicon • Single platform capable of LTE, 3G, WiMax, WiFi • OpenFlow for Layer 3 • Inexpensive ($300-500) Software Defined Networking (COMS 6998-8) Source: Katti, Stanford

  9. Design goals and Challenges Programmable wireless dataplane using off-the-shelf components • At least 40MHz OFDM-complexity performance • More than 200 GLOPS computation • Strict processing deadlines, eg. 25us ACK in WiFi • Modularity to provide ease of programmability • Only modify affected components, reuse the rest • Hide hardware details and stitching of modules Software Defined Networking (COMS 6998-8) Source: Katti, Stanford 9

  10. Wireless Basebands OFDM Demod Demap(BPSK) Deinterleave Viterbi Decode Descramble CRC Check Hdr Parse OFDM Demod OFDM Demod Demap(BPSK) Demap(64QAM) Demap(BPSK) Demap(64QAM) Deinterleave Deinterleave (UEP) Deinterleave (WiFi) Decode (1/2) Decode (3/4) Decode (1/2) Decode (3/4) Descramble CRC Check Hdr Parse Descramble Descramble CRC Check Hdr Parse Hdr Parse • WiFi 6mbps • WiFi 6, 18mbps and UEP • WiFi 6, 54mbps Software Defined Networking (COMS 6998-8) Source: Katti, Stanford 10

  11. Modular declarative interface Composing ACTIONS A A A A A B C C OFDM Demod A B E D D Demap(BPSK) C F G G F B Demap(64QAM) H H H C H B D E D I I I D Deinterleave (UEP) Deinterleave (WiFi) Blocks J J J J F G F Decode (3/4) Decode (1/2) • Data • flow F G H H J I I Descramble Hdr Parse CRC Check • Control • flow J H • 6M, 54M • UEP • 6M • 54M Rules: Branching logic • 6M Actions: DAGs of blocks I Software Defined Networking (COMS 6998-8) Inserting RULES Source: Katti, Stanford J

  12. State machines and deadlines • Start • decoding • Finish • decoding F B A D G C H I • deadline • Rules and actions encode the protocol state machine • Rules define state transitions • Each state has an associated action • Deadlines are expressed on state sequences Software Defined Networking (COMS 6998-8) Source: Katti, Stanford J 12

  13. Design principle IJudiciously scoping flexibility • Provide just enough flexibility • Keep blocks coarse • Higher level of abstraction • High performance through hardware acceleration • Viterbi co-processor • FFT co-processor • Off-the-shelf heterogeneous multicore DSPs • TI, CEVA, Freescale etc. Software Defined Networking (COMS 6998-8)

  14. Design principle IIProcessing-Decision separation A A B C B D • 60x C D E F F G H • 6M, 54M I • Logic pulled out to decision plane • Blocks and actions are branch-free • Deterministic execution times • Efficient pipelining, algorithmic scheduling • Hardware is abstracted out J

  15. Prototype • I/Q base- • band • samples • RF signal • (Analog) • (Digital) • Baseband-processor unit (BBU) • Antenna chain(AX) • Radio front end (RFE) • Layer 1 & 2 • Layer 0 & 1 • Layer 0 COTS TI KeyStone multicore DSP platform (EVM6618, two chips with 4 cores each at 1.2GHz, configurable hardware accelerators for FFT, Viterbi, Turbo) Prototype can process 40MHz, 108Mbps 802.11g on one chip using 3 of 4 cores Software Defined Networking (COMS 6998-8) Source: Katti, Stanford 15

  16. OpenRadio: Current Status OpenRadio APs with full WiFi/LTE software on TI C66x DSP silicon OpenRadio commodity WiFi APs with a firmware upgrade Network OS under development Software Defined Networking (COMS 6998-8) Source: Katti, Stanford

  17. Software architecture • BBU • RFE • AX • (Digital) • (Analog) • OR Wireless Decision Plane • protocol state machine, flowgraph composition, block configurations, knowledge plane, RFE control logic • monitor & control • OR Runtime System • compute resource scheduling, deterministic execution ensuring protocol deadlines are met • OR Wireless Processing Plane • deterministic signal processing blocks, header parsing, channel resource scheduling, multicore fifo queues, sample I/O blocks • data in • data out • Bare-metal with drivers Software Defined Networking (COMS 6998-8)

  18. Summary Provides programmatic interfaces to monitor and program wireless networks • High performance substrate using merchant silicon Software Defined Networking (COMS 6998-8)

  19. Outline • Review • Midterm • SDN and Middleboxes • SDN Wireless Networks • Motivation • Data Plane Abstraction: OpenRadio • Control Plane Architecture • Radio Access Networks: SoftRAN • Core Networks: SoftCell Software Defined Networking (COMS 6998-8)

  20. LTE Radio Access Networks • Goal: high capacity wide-area wireless network Base Station (BS) Serving Gateway Packet Data Network Gateway User Equipment (UE) Internet Serving Gateway access core Software Defined Networking (COMS 6998-8)

  21. Coping with Increasing Traffic • Increasing demand on wireless resources • Dense deployments • Radio resource management (RRM) decisions made at one base stations affect neighboring base stations • RRM needs to be coordinated Software Defined Networking (COMS 6998-8)

  22. Radio Resource Management: Interference • (Power used at BS1) affects (interference seen at Client 2) • (Interference seen at Client 2) affects (power required at BS2) BS2 BS1 Client1 Client2 Software Defined Networking (COMS 6998-8)

  23. Radio Resource Management : Mobility • Coordination required to decide handovers • Load at BS1 reduces and load at BS2 increases BS2 BS1 Client1 Client1 Software Defined Networking (COMS 6998-8)

  24. LTE-RAN: Current Architecture • Distributed control plane • Control signaling grows with density • Inefficient RRM decision making • Harder to manage and operate the network • Clients need to resynchronize state at every handover • Works fine with sparse deployments, but problems compound in a dense network Software Defined Networking (COMS 6998-8)

  25. SoftRAN: Big Base Station Abstraction Big Base Station Radio Element 1 time controller frequency Radio Element 2 Radio Element 3 time time time frequency radio element frequency frequency

  26. Radio Resource Allocation Flows 3D Resource Grid time radio element frequency Software Defined Networking (COMS 6998-8)

  27. SoftRAN: SDN Approach to RAN Coordination : X2 Interface Control Algo Control Algo OS OS Packet Tx/Rx Control Algo Packet Tx/Rx OS Packet Tx/Rx BS1 BS3 Control Algo Control Algo BS5 OS OS Packet Tx/Rx Packet Tx/Rx BS2 BS4 Software Defined Networking (COMS 6998-8)

  28. SoftRAN: SDN Approach to RAN Control Algo Operator Inputs Network OS Packet Tx/Rx Packet Tx/Rx Packet Tx/Rx BS1 BS3 BS5 Packet Tx/Rx Packet Tx/Rx BS2 BS4 Software Defined Networking (COMS 6998-8)

  29. SoftRAN Architecture Summary CONTROLLER RAN Information Base Periodic Updates Controller API • Bytes • Rate • Queue • Size Network Operator Inputs RADIO ELEMENTS QoS Constraints Interference Map Flow Records 3D Resource Grid Radio Resource Management Algorithm Radio Element API Time Radio Element POWER FLOW Frequency

  30. SoftRAN Architecture: Updates • Radio element -> controller (updates) • Flow information (downlink and uplink) • Channel states (observed by clients) • Network operator -> controller (inputs) • QoS requirements • Flow preferences Software Defined Networking (COMS 6998-8)

  31. SoftRAN Architecture: Controller Design • RAN information base (RIB) • Update and maintain global network view • Interference map • Flow records • Radio resource management • Given global network view: maximize global utility • Determine RRM at each radio element Software Defined Networking (COMS 6998-8)

  32. SoftRAN Architecture: Radio Element API • Controller -> radio element • Handovers to be performed • RF configuration per resource block • Power allocation and flow allocation • Relevant information about neighboring radio elements • Transmit Power being used Software Defined Networking (COMS 6998-8)

  33. SoftRAN: Backhaul Latency controller time radio element frequency Software Defined Networking (COMS 6998-8)

  34. Refactoring Control Plane • Controller responsibilities: • Decisions influencing global network state • Load balancing • interference management • Radio element responsibilities: • Decisions based on frequently varying local network state • Flow allocation based on channel states Software Defined Networking (COMS 6998-8)

  35. SoftRAN Advantages • Logically centralized control plane: • Global view on interference and load • Easier coordination of radio resource management • Efficient use of wireless resources • Plug-and-play control algorithms • Simplified network management • Smoother handovers • Better user-experience Software Defined Networking (COMS 6998-8)

  36. SoftRAN: Evolving the RAN • Switching off radio elements based on load • Energy savings • Dynamically splitting the network into Big-BSs • Handover radio elements between Big-BSs Software Defined Networking (COMS 6998-8)

  37. Implementation: Modifications • SoftRAN is incrementally deployable with current infrastructure • No modification needed on client-side • API definitions at base station • Femto API : Standardized interface between scheduler and L1 (http://www.smallcellforum.org/resources-technical-papers) • Minimal modifications to FemtoAPI required Software Defined Networking (COMS 6998-8)

  38. Implementation (Ongoing): Controller • Floodlight : controller implementation • Radio resource management algorithm • Load balancing • Interference management • QoS constraints • Network operator preferences Software Defined Networking (COMS 6998-8)

  39. Future Work • Expand SoftRAN to include 3G and Wifi networks • RAN virtualization to support resource sharing among multiple operators Software Defined Networking (COMS 6998-8)

  40. Outline • Review • Midterm • SDN and Middleboxes • SDN Wireless Networks • Motivation • Data Plane Abstraction: OpenRadio • Control Plane Architecture • Radio Access Networks: SoftRAN • Core Networks: SoftCell Software Defined Networking (COMS 6998-8)

  41. Cellular Core Network Architecture Base Station (BS) Serving Gateway Packet Data Network Gateway User Equipment (UE) Internet Serving Gateway access core Software Defined Networking (COMS 6998-8)

  42. Cellular core networks are not flexible • Most functionalities are implemented at Packet Data Network Gateway • Content filtering, application identification, stateful firewall, lawful intercept, … • This is not flexible Packet Data Network Gateway Software Defined Networking (COMS 6998-8)

  43. Cellular core networks are not scalable A lot of processing and state! Base Station Serving Gateway Packet Data Network Gateway User Equipment Internet Serving Gateway access core Software Defined Networking (COMS 6998-8)

  44. Cellular core networks are not cost-effective Capex & Opex Base Station Serving Gateway Packet Data Network Gateway User Equipment Internet Serving Gateway access core Software Defined Networking (COMS 6998-8)

  45. Can we make cellular core networks like data center networks? ✔Flexible ✔Scalable ✔Cost-Effective Software Defined Networking (COMS 6998-8)

  46. Can we make cellular core networks like data center networks? ✔Flexible ✔Scalable ✔Cost-Effective Yes! With SoftCell! Software Defined Networking (COMS 6998-8)

  47. SoftCell Overview Commodity hardware No change No change + SoftCellsoftware Controller Internet Software Defined Networking (COMS 6998-8)

  48. SoftCell: Taking Control ofCellular Core Networks • Characteristics of Cellular Core Networks • Scalable Data Plane • Asymmetric Edge: Packet Classification • Core: Multi-Dimensional Aggregation • Scalable Control Plane • Hierarchical Controller Software Defined Networking (COMS 6998-8)

  49. Characteristics of Cellular Core Networks • “North south” traffic pattern: in cellular core networks, most traffic is from/to the Internet • In data centers, 76% traffic is intra data center traffic. [Cisco Global Cloud Index] Software Defined Networking (COMS 6998-8)

  50. Characteristics of Cellular Core Networks • “North south” traffic pattern • Asymmetric edge: low-bandwidth access edge vs. high-bandwidth gateway edge Internet Access Edge GatewayEdge ~1 million UEs ~10 million flows ~400 Gbps – 2 Tbps ~1K UEs ~10K flows ~1 – 10 Gbps Software Defined Networking (COMS 6998-8)

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