Wireless SDN 기술. Seungwon Shin KAIST

Transcription

1 Wireless SDN 기술 Seungwon Shin KAIST

2 Background First, we need to talk about traditional network devices Consist of two main components Control path (plane) decision module (e.g., routing) Data path (plane) packet forwarding module

3 Problem with Internet Infrastructure? Routing, management, mobility management, access control, VPNs, Feature Operating System Feature Million of lines of source code RFCs Specialized Packet Forwar ding Hardware Billions of gates Bloated Power Hungry Vertically integrated, complex, closed, proprietary Not suitable for experimental ideas Not good for network owners & users; Not good for researchers.

4 Problem of Legacy Network Devices Too complicated Control plane is implemented with complicated S/W and ASIC Closed platform Vendor specific Hard to modify (nearly impossible) Hard to add new functionalities New proposal: Software Defined Networking Separate the control plane from the data plane

5 Software Defined Networking (SDN) Three layers Application layer Application part Implements logic Control layer (controller) Kernel part Runs applications Infrastructure layer Network switch or router Control Path Data Path OpenFlow From Open Networking Foundation

6 The Software-defined Network 3. Well-defined open API App App App 2. At least one good operating system Extensible, possibly open-source Network Operating System 1. Open interface to hardware Simple Packet For warding Hardwar e Simple Packet For warding Hardwar e Simple Packet For warding Hardwar e Simple Packet For warding Hardwar e Simple Packet For warding Hardwar e Slide from Nick McKeown at Stanford

7 Trend App App App App App App Windows Windows Windows (OS) (OS) (OS) Linux Linux Linux Mac Mac Mac OS OS OS Controller Controller NOX 1 1 (Network OS) Controller Controller Network 2 OS Virtualization layer x86 (Computer) Virtualization or Slicing OpenFlow Computer Industry Network Industry Slide from Nick McKeown at Stanford

8 SDN Operation L2 Forwarding a pplication Controller (e.g., NOX) SDN Controller (1) (5) (2) (3) SDN Switch (4) Host A A B: Forward Host B Flow Table in SDN Switch

9 Wireless Network with SDN For researcher New wireless network environment SoftRAN Software Defined Cellular For practitioner Seamless handover Odin project Manage home gateway system Bismark project

10 SoftRAN People Aditya Gufipati, Daniel Perry, Li Erran Li, Sachin Katti Stanford University, Bell Labs Goal Design software-defined (centralized) control plane for radio access networks

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14 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 Slide from Li Erran Li at Columbia

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23 SoftRAN: SDN Approach to RAN Coordination : X2 Interface Control Algo OS Packet Tx/Rx Control Algo OS Packet Tx/Rx Control Algo OS BS1 Control Algo OS BS3 Control Algo OS Packet Tx/Rx BS5 Packet Tx/Rx Packet Tx/Rx BS2 BS4 Slide from Li Erran Li at Columbia

24 SoftRAN: SDN Approach to RAN Control Algo Operator Inputs Network OS Packet Tx/Rx BS1 BS3 Packet Tx/Rx Packet Tx/Rx BS5 Packet Tx/Rx Packet Tx/Rx BS2 BS4 Slide from Li Erran Li at Columbia

25 SoftRAN Architecture Summary CONTROLLER Periodic Updates RADIO ELEMENTS Controller API Interference Map RAN Information Base Bytes Rate Queue Size Flow Records Network Operator Inputs QoS Constraints Radio Element API POWER FLOW Frequency Radio Element 3D Resource Grid Radio Resource Management Algorithm Slide from Li Erran Li at Columbia

26 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 Slide from Li Erran Li at Columbia

27 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 Slide from Li Erran Li at Columbia

28 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 Slide from Li Erran Li at Columbia

29 time SoftRAN: Backhaul Latency controller Slide from Li Erran Li at Columbia

30 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 Slide from Li Erran Li at Columbia

31 Implementation (Ongoing): Controller Floodlight : controller implementation Radio resource management algorithm Load balancing Interference management QoS constraints Network operator preferences Slide from Li Erran Li at Columbia

32 CellSDN People Laurent Vanbever, Xin Jin, Li Erran Li, Jennifer Rexford Princeton University, Bell Labs Goal Change cellular networks as a kind of Software-Defined Network

33 CellSDN Slide from Li Erran Li at Columbia

34 CellSDN No clear separation of control plane and data plane Control Plane Data Plane Mobility Mana gement Entity ( MME) Home Subsc riber Server (HSS) Policy Control and Charging Rules Fu nction (PCRF) Problem with Intertechnology (e.g. 3G to LTE) handoff Problem of inefficient radio resource allocation User Equip ment (UE) Base Serving Packet Data Network Station Gateway Gateway (enodeb) (S-GW) (P-GW) Slide from Li Erran Li at Columbia

35 CellSDN Architecture CellSDN provides scalable, fine-grain real time control with extensions: Controller: fine-grain policies on subscriber attributes Switch software: local control agents to improve control plane scalability Switch hardware: fine-grain packet processing to support DPI Base stations: remote control and virtualization to enable flexible real time radio resource management

36 CellSDN Slide from Li Erran Li at Columbia

37 CellSDN Slide from Li Erran Li at Columbia

38 BISMark Project People GIT Lead by Prof. Nick Feamster Goal Measuring access link performance What factors affect performance? Measuring application performance Study of Web download times Representing performance to users Performance does not just depend on throughput What other factors matter? How to represent them to users? Slide from Nick Feamster at GIT

39 Challenge: Confounding Factors From Gateway Downstream Upstream 5.62 Mbit/s 452 Kbits/s Slide from Nick Feamster at GIT 39

40 BISMark: A View from the Gateway Periodic measurements to last mile and end-to-end Measure directly at the gateway device Adjust for confounding factors Slide from Nick Feamster at GIT 40

41 BISMark Deploy programmable gateways in homes Deployment NOX Box NetGear WNDR 3700, others SamKnows about 10,000 around the U.S. Netgear WNDR 3700 NoxBox Netgear 3500L Slide from Nick Feamster at GIT

42 Odin People Lead by Laith Suresh and Prof. Anja Feldman TU-Berlin Goal Provide seamless handoff to wireless network users

43 Odin Motivation Current wireless network environments are Vendor lock-in inflexible Slide from Laith Suresh at TU-Berlin

44 Odin Approach Enterprise WLAN services as network applications Requirements Should not modify client Should be simple in programming Slide from Laith Suresh at TU-Berlin

45 Odin How to LVAP Light Virtual AP LVAP migration Equal to Handoff Seamless handoff by Removing/Adding LVAP dynamically Slide from Laith Suresh at TU-Berlin

46 Odin Evaluation Normal client Odin client

47 Summary SDN? New network architecture Dynamic flow control, programmability, and more Usually employ into a wired-network environment However, Many people (mostly researchers) try to move this idea into a wireless network environment We don t know if it is successful But, we need to try and find something