Computer Network : set of computers connected together for the purpose of

sharing resources

Software-defined networking (SDN) : Approach to allow network

administrators to programmatically initialize, control, change, and manage

network behavior dynamically

Network Switch : connects devices together using packet switching

Hub : common connection point for devices in a network,used to connect segments

of a LAN

Router : forwards data packets between computer networks

Current Internet Closed to Innovations in the Infrastructure

n

n

Specialized Packet Forwarding Hardware

n

Specialized Packet Forwarding Hardware

“Software Defined Networking”approach to open it

Network Operating System

App App App

n

n

Specialized Packet Forwarding Hardware

n

Specialized Packet Forwarding Hardware

The “Software-defined Network”

Network Operating System

App App App

3.Well Defined Open API

2. At least one good operating systemExtensible, possibly open-source

Simple PacketForwardingHardware

Simple PacketForwardingHardware

Simple PacketForwardingHardware

1. Open interface to hardware

OpenFlow - Defintion

• enabler of SDN

• first standard communication interface defined between the

control and forwarding layers of SDN Architecture

• needed to move network control out of proprietary network

switches into control software that's open source

• mainly used between switch and controller as a secure channel

• layered on top of the Transmission Control Protocol(TCP)

• controllers listen on TCP port 6653 for the switches to connect

Data Path (Hardware)

Control Path OpenFlow

OpenFlow Controller

OpenFlow Protocol (SSL/TCP)

Components of OpenFlow Network

OpenFlow Controller

Manages one or more switch via OpenFlow channels

Uses OpenFlow protocol to communicate with a OpenFlow aware

switch

OpenFlow Channel

Used to exchange OpenFlow message between switch and controller

OpenFlow Switch

Consists of one or more flow tables,group table and meter table

Single switch can be manages by one or more controllers

Flow tables and group tables are used during the lookup or forwading

phase

Meter table is used to perform simple QOS operations

OpenFlow Basics

SwitchPort

MACsrc

MACdst

Ethtype

VLANID

IPSrc

IPDst

IPProt

L4sport

L4dport

Rule

+ mask what fields to match10

VLANpcp

IPToS

Flow entries : instructions that tell an openflow switch what to do with an incoming

stream of packets and the are stored in the flow table

Operating Modes

Reactive

• First packet of flow triggers

controller to insert flow entries

• Efficient use of flow table

• Every flow incurs small additional

flow setup time

• If control connection lost, switch

has limited utility

Proactive

•Controller pre-populates flow table in

switch

•Essentially requires aggregated

(wildcard) rules

•Zero additional flow setup time

•Loss of control connection does not

disrupt traffic

11

Reactive vs. Proactive (pre-populated)

Both models are possible with OpenFlow

Centralized Control

OpenFlowSwitch

OpenFlowSwitch

OpenFlowSwitch

Controller

Distributed Control

OpenFlowSwitch

OpenFlowSwitch

OpenFlowSwitch

Controller

Controller

Controller

Centralized vs Distributed Control

Both models are possible with OpenFlow

Control Modes

Flow Routing vs. AggregationBoth models are possible with OpenFlow

Flow-Based

• Every flow is individually

set up by controller

• Exact-match flow entries

• Flow table contains one

entry per flow

• Good for fine grain

control, e.g. campus

networks

Aggregated

•One flow entry covers large

groups of flows

•Wildcard flow entries

•Flow table contains one

entry per category of flows

•Good for large number of

flows, e.g. backbone

13

Simple Packet Forwarding Hardware

Network Operating System 1

Open interface to hardware

Virtualization or “Slicing” Layer

Network Operating System 2

Network Operating System 3

Network Operating System 4

App App App App App App App App

Many operating systems, orMany versions

Open interface to hardware

Isolated “slices”

Simple Packet Forwarding Hardware

Simple Packet Forwarding Hardware

Simple Packet Forwarding Hardware

Simple Packet Forwarding Hardware

Virtualizing

OpenFlow

Summary

• OpenFlow/SDN is evolving to facilitate an ecosystem for innovation

• OpenFlow is being deployed in over 100 organizations world-wide

– GEC9 in Nov, 2010 showcased nation-wide OF

– Internet 2 and NLR starting to serve as the GENI Backbone

• OpenFlow is essential for Service Providers

– Custom control for Traffic Engineering

– Combined Packet/Circuit switched networks

Are you innovating in your

network?