OBS光突发交换简介

OpportunitiesandChallengesforOpticalBurstswitching2•WhyOBS?•backgroundandcharacter•TheprincipleofOBS•architectureofOBSnode•ProtocolofOBS•contentionresolution•opticalpacketassemblymechanism•Applicationandfuture•LOBS(LabelOpticalBurstSwitching)overview3•today:IPover(ATM/SONET)overWDM•trend:IntegratedIP/WDM(withopticalswitching)•goal:ubiquitous,scalableandfuture-proofNetworkArchitectures4•trend:IntegratedIP/WDM(withopticalswitching)•goal:ubiquitous,scalableandfuture-proofNetworkArchitectures5ProgressinOpticalNetworksCapacityFunctionRingMeshDynamicStaticOpticalPacketPt-to-PtSingleChannelWDMOpticallyAmplifiedOpticalAdd/DropTopologyOpticalCircuitSwitchingOpticalBurstSwitchingOpticalPacketSwitchingProgressinOpticalNetworks6Underthesamenetworkconditions,OBSnetworkscanachieve20%~30%morethroughputthanthoseinOCSnetworks.ThroughputcomparisonOBSvs.OCS7Data-centric+High-BandwidthPacket+OpticalmoderategranularityCost-effectiveservicedeliveryandflexibilityAvoidelectricalRAMandO/E/Obottleneck–DRAMgettingfasteronlyby7%/year–O/E/OconversionconsumespowerandspaceScalabilityforfuturebandwidthgrowthsUseopticalparallelismforsimplerswitchingfabricFromATM/SONETtoIP/WDMparadigmMotivationsforOpticalOBSSwitching8architectureofOBSnodeProtocolofOBScontentionresolutionopticalpacketassemblymechanismPrincipleofOBS9WirelineO-CDMALANLegacyMANFreeSpaceandWirelineO-CDMALANOpticalCoreNetworkEdgerouterEdgerouterOLSroutersOLSswitchesStarCouplerMANStarCouplerMANEdgerouterLegacyLANOLSswitchesSENSORNetworksNextGenerationNetworkTopology10fiberdelayDEMUXNC&MSwitchingFabricLabelProcessingModule-TI(LP-TI)LabelProcessingModules-CI(LP-CI)CICICIOLEOLROLEOLROLEOLRIPRouterATMClientMachineUNASlabelreaderSwitchControllerw/ForwardingLook-upTableOLSEdgeRouterExampleofanOLSRforIP,ATMorclient-specifictrafic11RapidTuning(~1nsec)ofT_WCtoachieveswitchinginWavelength,Time,SpacedomainsScalableto42Petabit/seccapacity32*(2562x2562)connectivityT_WCT_WCT_WCT_WCF_WCF_WCF_WCF_WCswitchcontrolTunableWavelengthConvertersl-router(AWGR)controllerTIMEWAVELENGTHSPACEFixedWavelengthConvertersOpticalSwitchFabricusedinCoreRouters12OLSCoreandEdgeRouters13IPClientNetworkOpticalLabelSwitchingNetworkCoreRouterEdgeRouterPayloadLabelIPClientNetworkEdgeRouterCoreRouterCoreRouterPhysicalLayerInterfaceEncapsulationLabelprocessingUnitDatabustrafficcontrollerDataBusSONETPPPPhysicalLayerInterfaceDatabustrafficcontrollerAOLSInterfacePOSInterfaceIngressPathEgressPathEdgeRouterL1P1L3P3L1,L2P1,P2L2P2P1,P2,P3P1,P2,P3L1,L2,L3P1IPClient-to-IPClientwithCascadedOperationofOLSRs14TAG(tell-and-go)IBT(in-band-terminator)RFD(Reserve-a-Fixed-Time)JET(just-enough-time)OpticalBurstSwitchingProtocol15T(i)=T-Σδ(h)OpticalBurstSwitchingProtocol16BufferMemoryMACcontroller•Buffer,Schedule,andForward•ElectronicRAM--DiverseFunctions•ContentionResolution,Queuing,etcinTimeBufferMemoryMACBufferMemoryMACBufferMemoryMACBufferMemoryBufferMemoryBufferMemoryMACBufferMemoryBufferMemoryBufferMemoryMACBufferMemoryBufferMemoryBufferMemoryMACBufferMemoryBufferMemoryBufferMemoryMACSPACETIMEConventionalElectronicPacketSwitches17ContentionResolutionWavelengthdomain•anewdimensionavailableinopticalnetworks•notinducetimingjitteroradditionallatencyTimedomain•FDL:usesalimitednumberofdiscretefiberdelaylinesspacedomain•deflectionroutingmulti-techniquecombination:Moreeffective18packetarrivescontention?lcont.res.?timecont.res.?spacecont.res.?SendtoEdgeRouterforcont.res.ordropyesnononoforwardnoyesyesyes•S.Yao,S.J.B.Yoo,andB.Mukherjee,“Acomparisonstudybetweenslottedandunslottedall-opticalpacket-switchednetworkwithpriority-basedrouting,”OFC2001,#TuK2•S.Yao,S.J.B.Yoo,B.Mukherjee,S.Dixit,“Hybridcontentionresolutionforanopticalpacket-switchednetworkwithself-similarIPtraffic,”APOC2001#4585-04.•S.Yao,B.Mukherjee,S.J.BenYoo,andS.Dixit,“All-opticalPacket-switchingforMetropolitanAreaNetworks:OpportunitiesandChallanges,”IEEEComm.Magazine,vol.39,p.142-8(2001)•S.J.B.Yoo,Y.Bansal,Z.Pan,J.Cao,V.K.Tsui,S.K.H.Fong,Y.Zhang,J.Taylor,H.J.Lee,M.Jeon,V.Akella,K.Okamoto,S.Kamei,“Optical-LabelSwitchingbasedPacketRoutingSystemwithContentionResolutionCapabilitiesinWavelength,Time,andSpaceDomains,”OFC2002,paper#WO2(2002).ContentionResolutionAlgorithm19•AssemblealargeropticalpacketfromIPpacketsbasedondestinationandQoS•Thecreationofanopticalpacket:–ReachtheMaximumPayloadSize(MPS)–ExpirationofAssemblyTime-outPeriod(T)MPSOpticalPacketAssemblyMechanism20MPS•AssemblealargeropticalpacketfromIPpacketsbasedondestinationandQoS•Thecreationofanopticalpacket:–ReachtheMaximumPayloadSize(MPS)–ExpirationofAssemblyTime-outPeriod(T)OpticalPacketAssemblyMechanism21MPS•AssemblealargeropticalpacketfromIPpacketsbasedondestinationandQoS•Thecreationofanopticalpacket:–ReachtheMaximumPayloadSize(MPS)–ExpirationofAssemblyTime-outPeriod(T)OpticalPacketAssemblyMechanism22MPS•AssemblealargeropticalpacketfromIPpacketsbasedondestinationandQoS•Thecreationofanopticalpacket:–ReachtheMaximumPayloadSize(MPS)–ExpirationofAssemblyTime-outPeriod(T)OpticalPacketAssemblyMechanism23MPS•Assemble