教程案例講稿1

1、Towards an Elastic Distributed SDN ControllerAdvait Dixit, Fang Hao, Sarit Mukherjee, T.V. Lakshman, Ramana KompellaPhysical Network InfrastructureSDN Control PlaneDistributed Control PlaneSingle point of failurePerformance bottleneckSpatial PartitioningOverloadGrowing the Control PlaneShrinking the

2、 Control PlaneGoalsBuild a distributed control plane whichLoad balancesGrowsShrinksThis requiresLoad estimation at controllersSwitch migration protocolNave Switch MigrationSLAVEMASTERMASTERSLAVERole Change to MasterProblem With Nave Switch MigrationPacket-InMASTERMASTERSLAVESLAVEPacket-OutRole Chang

3、e to MasterPacket-Out from Slave is droppedMigration Protocol RequirementsSafety: Exactly 1 controller processes every message from the switchLiveness: For each switch, at least 1 controller is active at all timesOpenflow compliantFlow-AddFlow-DeleteFlow-Removed4-Phase Switch Migration ProtocolMASTE

4、RSLAVEFlow-RemovedEQUALRole Change to MasterSLAVEMASTERRole Change to EqualBarrier RequestBarrier ReplyPhase 1: Change from Slave to EqualPhase 2: Insert and remove dummy flowPhase 3: Flush in-flight messagePhase 4: Change from Equal to MasterA Mininet TestbedProblem: Cannot generate sufficient traf

5、fic for a large distributed control planeveth PairOpenvSwitchOpenvSwitchveth PairOpenvSwitchveth PairEmulation HostA Multi-Host Mininet TestbedOpenvSwitchOpenvSwitchOpenvSwitchOpenvSwitchOpenvSwitchOpenvSwitchEmulation HostOpenvSwitchOpenvSwitchOpenvSwitchGRE TunnelGRE TunnelGRE TunnelEmulation Host

6、Emulation HostEvaluationEvaluationNext Step: ElastiConPhysical Network InfrastructureCore Controller ModuleApplication 1Application 2Core Controller ModuleApplication 1Application 2Distributed Data Store (e.g., Hazelcast)Node 1Load MeasurementsLoad BalanceScale UpScale DownLoad Adaptation DecisionsD

7、istributed SDN Control PlaneNode 2Actions:Migrate switchRemove controllerAdd controllerThank youDistributed Control Plane in a DatacenterMedian flow arrival rate requires 1-5 controllers, peak requires 150*Distributed control plane should grow and shrinkFlow arrival rates vary across switches and ti

8、meNeed a switch migration (handover) protocol* Calculations based on Benson et al, IMC 2010Distributed SDN Control PlanePhysical Network InfrastructureCore Controller ModuleDistributed Data Store (e.g., Hazelcast)Controller Node 1Controller Node 2Application 1Application 2Core Controller ModuleAppli

9、cation 1Application 2Hazelcast Client StubNext StepsBuild a control loop and algorithms for dynamically:Changing switch-controller mapping basedGrowing and shrinking distributed controllerThanks! Questions?EvaluationNeed title for this slideFor a data center with 100K hosts:Peak flow arrival rate =

10、300M* flows/secMedian flow arrival rate = 1.5-10M* flows/secImpossible to predict flow arrival rates at a switchImplications:Distributed controller needs to grow and shrinkNeed a switch migration protocol* From Benson et al, IMC 2010New Problems in Distributed SDN ControllersHow to manage distribute

11、d state?Where to place controllers?How to write distributed controller applications?How many controllers?Which switch connects to which controller?New Problems in Distributed SDN ControllersHow to manage distributed state?Where to place controllers?How to write distributed controller applications?How many controllers?Which switch connects to which controller?Distributed SDN ControllerDistributed Global Network StatePhysical Network InfrastructureApplication 1Application 2Application 3