SDN and Wireless Network

Seungwon Shin KAIST

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

Million of lines of source code

6000+ RFCs

Billions of gates Bloated Power Hungry

Vertically integrated, complex, closed, proprietary

Not suitable for experimental ideas

Specialized Packet Forwarding Hardware

Operating System

Feature Feature

Routing, management, mobility management, access control, VPNs, …

Problem with Internet Infrastructure?

Not good for network owners & users; Not good for researchers.

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

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

OpenFlow

From Open Networking Foundation

Control Path

Data Path

App

Simple Packet Forwarding Hardwar

e

Simple Packet Forwarding Hardwar

e

Simple Packet Forwarding Hardwar

e

App App

Simple Packet Forwarding Hardwar

e Simple Packet Forwarding Hardwar

e

Network Operating System

1. Open interface to hardware

3. Well-defined open API 2. At least one good operating system

Extensible, possibly open-source

The “Software-defined Network”

Slide from Nick McKeown at Stanford

Windows (OS)

Windows (OS)

Linux Mac OS

x86 (Computer)

Windows (OS)

App App

Linux Linux Mac OS

Mac OS

Virtualization layer

App

Controller 1

App App

Controller 2

Virtualization or “Slicing”

App

OpenFlow

Controller 1

NOX (Network OS)

Controller 2 Network OS

Trend

Computer Industry Network Industry

Slide from Nick McKeown at Stanford

SDN Operation

SDN Switch

Host A Host B

L2 Forwarding application

(1) (2) (3)

Controller (e.g., NOX)

SDN Controller

(5)

A B: Forward

Flow Table in SDN Switch

(4)

Wireless Network with SDN

• For researcher • New wireless network environment

• OpenRoad • Software Defined Cellular

• For practitioneer • Seamless handover

• Odin project • Manage home gateway system

• Bismark project

OpenRoad

• People • KK Yap and Guru Palrukar at Stanford University

• Goal

• Provide efficient wireless network services with SDN

OpenRoad

• What they want

Slide from KK Yap at Stanford

OpenRoad

• Overall scenario • Use SNMP protocol to check the

availability of Aps • Each network controller operates

different network applications • Each user can share APs, but they

can see different network • Network virtualization

CellSDN

Slide from Li Erran Li at Columbia

CellSDN

• Problem with Inter-technology (e.g. 3G to LTE) handoff

• Problem of inefficient radio resource allocation

User Equipment (UE)

Gateway (S-GW)

Mobility Management Entity (MME)

Network Gateway (P-GW)

Home Subscriber Server (HSS)

Policy Control and Charging Rules Function (PCRF)

Station (eNodeB)

Base Serving Packet Data

Control Plane Data Plane

• No clear separation of control plane and data plane

Slide from Li Erran Li at Columbia

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

CellSDN

Slide from Li Erran Li at Columbia

CellSDN

Slide from Li Erran Li at Columbia

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

Challenge: Confounding Factors

19

Downstream Upstream

5.62 Mbit/s 452 Kbits/s

From Gateway

Slide from Nick Feamster at GIT

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

20 Slide from Nick Feamster at GIT

BISMark

Deploy programmable gateways in homes Deployment

NOX Box NetGear WNDR 3700, others

SamKnows about 10,000 around the U.S.

NoxBox Netgear 3500L

Netgear WNDR 3700

Slide from Nick Feamster at GIT

Odin

• People • Lead by Laith Suresh and Prof. Anja Feldman

• TU-Berlin

• Goal • Provide seamless handoff to wireless network users

Odin

• Motivation • Current wireless network environments are

• Vendor lock-in • inflexible

Slide from Laith Suresh at TU-Berlin

Odin

• Approach • Enterprise WLAN services as network applications

• Requirements • Should not modify 802.11 client • Should be simple in programming

Slide from Laith Suresh at TU-Berlin

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

Odin

• Evaluation

Normal 802.11 client Odin client

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