Software Defined Networksand OpenFlowSDN CIO Summit 2010

Nick McKeown & Guru ParulkarStanford UniversityIn collaboration with Martin Casado and Scott ShenkerAnd contributions by many others

Executive SummaryThe network industry is starting to restructureThe trend: Software Defined NetworksSeparation of control from datapathFaster evolution of the networkIt has started in large data centersIt may spread to WAN, campus, enterprise, home and cellular networksGENI is putting SDN into hands of researchers*

Whats the problem?*

Cellular industryRecently made transition to IPBillions of mobile usersNeed to securely extract payments and hold users accountable

IP sucks at both, yet hard to change

How can they fix IP to meet their needs?

*

Telco Operators Global IP traffic growing 40-50% per yearEnd-customer monthly bill remains unchangedTherefore, CAPEX and OPEX need to reduce 40-50% per Gb/s per yearBut in practice, reduces by ~20% per year

How can they stay in business?How can they differentiate their service?*

Trend #1(Logical) centralization of control*

Already happeningEnterprise WiFiSet power and channel centrallyRoute flows centrally, cache decisions in APsCAPWAP etc.

Telco backbone networksCalculate routes centrallyCache routes in routers*

Experiment: Stanford campusHow hard is it to centrally control all flows?

How many $400 PCs to centralize all routing and all 137 policies?Controllers[Ethane, Sigcomm 07]EthernetSwitch

EthernetSwitch

EthernetSwitch

EthernetSwitch

Answer: * less than one

If you can centralize control, eventually you will.

With replication for fault-tolerance and performance scaling. *

How will the network be structured?*

5900 RFCsBarrier to entryBloatedPower HungryVertically integratedMany complex functions baked into the infrastructureOSPF, BGP, multicast, differentiated services, Traffic Engineering, NAT, firewalls, MPLS, redundant layers,

Looks like the mainframe industry in the 1980s

The Current Network*

Restructured Network*

Trend #2Software-Defined Network*

The Software-defined Network

OpenFlow*PacketForwarding

PacketForwarding

PacketForwarding

PacketForwarding

PacketForwarding

OpenFlow BasicsNarrow, vendor-agnostic interface to control switches, routers, APs, basestations.*

Network OSStep 1: Separate Control from Datapath*

Step 2: Cache flow decisions in datapathIf header = x, send to port 4If header = ?, send to meIf header = y, overwrite header with z, send to ports 5,6*FlowTableNetwork OS

Plumbing PrimitivesMatch arbitrary bits in headers:

Match on any header; or user-defined headerAllows any flow granularityActions:Forward to port(s), drop, send to controllerOverwrite header with mask, push or popForward at specific bit-rate

*HeaderDatae.g. Match: 1000x01xx0101001x

Ethernet Switch/Router

Data Path (Hardware)Control PathControl Path (Software)

Data Path (Hardware)Control PathOpenFlowOpenFlow ControllerOpenFlow Protocol (SSL)

The Software Defined Network

*Packet Forwarding

Packet Forwarding

Packet Forwarding

Packet Forwarding

Packet Forwarding

Network OSSeveral commercial Network OS in developmentCommercial deployments late 2010

ResearchResearch community mostly uses NOXOpen-source available at: http://noxrepo.orgExpect new research OSs late 2010 *

Software Defined Networks in Data Centers*

Example: New Data CenterCost200,000 serversFanout of 20 10,000 switches$5k vendor switch = $50M$1k commodity switch = $10M

Savings in 10 data centers = $400M

Control

More flexible controlQuickly improve and innovateEnables cloud networkingSeveral large data centers will use SDN.

Data Center NetworksExisting SolutionsTend to increase hardware complexityUnable to cope with virtualization and multi-tenancySoftware Defined NetworkOpenFlow-enabled vSwitchOpen vSwitch http://openvswitch.org Network optimized for data center ownerSeveral commercial products under development*

Software Defined Networks on College Campuses*

What we are doing at StanfordDefining the OpenFlow SpecCheck out http://OpenFlow.orgOpen weekly meetings at Stanford

Enabling researchers to innovateAdd OpenFlow to commercial switches, APs, Deploy on college campusesSlice network to allow many experiments*

Packet Forwarding

Packet Forwarding

Packet Forwarding

Packet Forwarding

Packet Forwarding

Some research examples*

FlowVisor Creates Virtual NetworksOpenFlowProtocolOpenFlowProtocolMultiple, isolated slices in the same physical network

Demo Infrastructure with Slicing

Application-specific Load-balancingInternetGoal: Minimize http response time over campus networkApproach: Route over path to jointly minimize

Intercontinental VM MigrationMoved a VM from Stanford to Japan without changing its IP. VM hosted a video game server with active network connections.

Converging Packet and Circuit NetworksIPRouterTDMSwitchWDMSwitchWDMSwitchIPRouterGoal: Common control plane for Layer 3 and Layer 1 networksApproach: Add OpenFlow to all switches; use common network OSOpenFlowProtocolOpenFlowProtocol[Supercomputing 2009 Demo][OFC 2010]

ElasticTree

Goal: Reduce energy usage in data center networksApproach: Reroute trafficShut off links and switches to reduce power[NSDI 2010]

ElasticTree

Goal: Reduce energy usage in data center networksApproach: Reroute trafficShut off links and switches to reduce power[NSDI 2010]

Executive SummaryThe network industry is starting to restructureThe trend: Software Defined NetworksSeparation of control from datapathFaster evolution of the networkIt has started in large data centersIt may spread to WAN, campus, enterprise, home and cellular networksGENI is putting SDN into hands of researchers*

Thank you*

*********