OpenFlow : Enabling Innovation in Campus Networks

SIGCOMM 2008

Nick McKeown, Tom Anderson, et el.Stanford University California, USA

2011. 04. 11Presented by Hyogi Jung

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Contents• Internet Closed for Innovations• OpenFlow– Goals– Concepts– Architecture– Flow Table Structure– Controller

• Summary

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Innovations in Legacy Internet

• Experiments we’d like to do new– Mobility management– Network-wide energy management– New naming/addressing schemes– Network access control

• Problem with our network– Paths are fixed– IP-only– Addresses dictated by DNS, DHCP, etc– No means to add our own processing

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Why Internet Closed for Innovations?

• Commercial Vendor won’t open software and hardware development environment– Complexity of support– Market protection and barrier to entry

• Hard to build my own– Prototypes are unstable– Software only : Too slow– Hardware/Software : Fanout too small

(need>100 ports for wiring closet)4/17

Experimenter’s Dream(Vendor’s Nightmare)

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StandardNetwork

Processinghwsw Experimenter writes

experimental codeon switch/router

User-defined

Processing

StandardNetwork

Processing

OpenFlow’s Goal• Put an open platform– researchers/students to test new ideas at scale

through production networks– without requiring vendors to expose internal

workings• Bring Future Internet to legacy Internet• An open development environment for all re-

searchers(e.g. Linux, Verilog, etc)

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OpenFlow Concept

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Ethernet SwitchControl Path (Software)

Data Path (Hardware)

Control Path

Data Path (Hardware)

OpenFlow

OpenFlow Controller

OpenFlow Protocol (SSL/TCP)

OpenFlow Network Architecture

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Controller

OpenFlow Switch

FlowTable

SecureChannel

PCOpenFlow

Protocol

SSL

hw

sw

OpenFlow Switch specification

Operation Step

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Controller

PC

OpenFlowSwitch

OpenFlowSwitch

OpenFlowSwitch

OpenFlowSwitch

New func-tion!

If header = x, send to port 4If header =y, overwrite header with z,

send to ports 5,6If header = ?, send to me

FlowTa-ble

FlowTa-ble

FlowTa-ble

FlowTa-ble

Packet Processing• OpenFlow SW’s Packet Processing– Search a matched entry of flow table with arriving

packet’s information

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Packetin from

NetworkFlow lookup

Send to securechannel

Apply actions

No match

Match

Flow Table Structure• Exploit flow table in switches, routers, and

chipsets

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Flow Table Entry

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SwitchPort

MACsrc

MACdst

Ethtype

VLANID

IPSrc

IPDst

IPProt

TCPsport

TCPdport

Rule Action Stats

1. Forward packet to port(s)2. Encapsulate and forward to controller3. Drop packet4. Send to normal processing pipeline

+ mask

Packet + byte counters

Flow Table Entry Examples(OpenFlow is Backward Compatible)

• Ethernet Switching

• IP Routing

• Application Firewall

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SwitchPort

MACsrc

MACdst

Ethtype

VLANID

IPSrc

IPDst

IPProt

TCPsport

TCPdport Action

* * 00:1F:. * * * * * * * port6

SwitchPort

MACsrc

MACdst

Ethtype

VLANID

IPSrc

IPDst

IPProt

TCPsport

TCPdport Action

* * * * * * 5.6.7.8 * * * port6

SwitchPort

MACsrc

MACdst

Ethtype

VLANID

IPSrc

IPDst

IPProt

TCPsport

TCPdport Action

* * * * * * * * * 22 drop

Flow Table Entry Examples(OpenFlow allows layers to be combined)

• Flow Switching

• VLAN + App

• Port + Ethernet + IP

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SwitchPort

MACsrc

MACdst

Ethtype

VLANID

IPSrc

IPDst

IPProt

TCPsport

TCPdport Action

port3 00:2E:.. 00:1F:. 0800 vlan1 1.2.3.4 5.6.7.8 4 17264 80 port6

SwitchPort

MACsrc

MACdst

Ethtype

VLANID

IPSrc

IPDst

IPProt

TCPsport

TCPdport Action

* * * * vlan1 * * * * 80 port6

SwitchPort

MACsrc

MACdst

Ethtype

VLANID

IPSrc

IPDst

IPProt

TCPsport

TCPdport Action

port3 00:2E:.. * 0800 * * 5.6.7.8 4 * 22 drop

OpenFlow Controller• Centralized Intelligential agency for entire

OpenFlow network• NOX is an open-source OpenFlow Controller• Researchers can insert their software code

into NOX controller for testing their idea

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Nox Controller

OpenFlow SwitchOpenFlow Switch OpenFlow Switch

OpenFlow Hardware (Switches)

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• NEC

• HP

• Pronto

Summary• OpenFlow– Standard way to control flow-tables in commercial

switches and routers– Put an open platform– An open development environment for all re-

searcher– Test Environment for Future Internet Technologies

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