文档介绍：该【光纤通信课程设计课件SONET-rev1 】是由【马克里思】上传分享，文档一共【109】页，该文档可以免费在线阅读，需要了解更多关于【光纤通信课程设计课件SONET-rev1 】的内容，可以使用淘豆网的站内搜索功能，选择自己适合的文档，以下文字是截取该文章内的部分文字，如需要获得完整电子版，请下载此文档到您的设备，方便您编辑和打印。AcrashcourseofSDHBackground(analogtelephony,TDM,PDH)/SDHhistoryandmotivationArchitecture(path,line,section)RatesandframestructurePayloadsandmappingsProtectionandringsVCATandLCASHandlingpacketdataOutlineBackgroundThePSTNcirca1900pairofcopperwires“localloop”manualroutingatlocalexchangeoffice(CO)Analogvoltagetravelsovercopperwireend-to-endVoicesignalarrivesatdestinationseverelyattenuatedanddistortedRoutingperformedmanuallyatexchangesoffice(s)RoutingisexpensiveandlengthyoperationRouteismaintainedfordurationofcallTelephonyMultiplexing1900:25%oftelephonyrevenueswenttocopperminesstandardwas18gauge,longdistanceevenheavierbatcross-talkneededmethodtoplacemultipleconversationsonasingletrunk1918:“Carriersystem”(FDM)5conversationsonsingletrunklaterextendedto12(group)stilllatersupergroups(60),mastergroups(60)),…fchannels8kHz12kHz4kHz16kHz20kHzTheDigitalizationofthePSTNShannon(BellLabs)provedthatmunicationsisalwaysbetterthanmunicationsandthePSTNbecamedigitalBettermeansMoreefficientuseofresources()Highervoicequality(lessnoise,lessdistortion)AddedfeaturesAftertheinventionofthetransistor,in1963T-carriersystem(TDM)1bytepersample–8000samplespersecondT1=24conversationspertrunk2groupspercable!ttimeslotsandswitchingbecameeasiertooComplexityincreasesrapidlywithsize124567831234567AnalogCrossbarswitchDigitalCross-connect(DXC)processort12345t21543OptimizedTelephonyRoutingCircuitswitching(routeismaintainedfordurationofcall)Route“set-up”isanexpensiveoperation,justasitwasformanualswitchingplexleastcostroutingalgorithmsareusedCalldurationconsistsofset-up,voiceandtear-downphasesThePSTN(work)circa1960localloopsubscriberlineworkAnalogvoltagesusedthroughout,butextensiveFrequencyDivisionMultiplexingVoicesignalarrivesatdestinationafteramplificationandfilteringto4KHzAutomaticroutingUniversaldial-toneVoltageandtonesignalingCircuitswitching(routeismaintainedfordurationofcall)trunkscircuitsThePresentPSTNsubscriberlineAnalogvoltagesandcopperwireusedonlyin“lastmile”,butcoredesignedtomimicoriginalsituationworkworkExtensiveuseoffiberopticandwirelessphysicallinksT1/E1,/SDH“synchronous”protocolsSignalingcanbechannel/work(SS7)AutomaticroutingCircuitswitching(routeismaintainedfordurationofcall)Complexroutingoptimizationalgorithms(LP,Karmarkar,etc)workclass5switchclass5switchtandemswitchlastmileTDMtimingTimeDomainMultiplexingreliesonallchannels(timeslots)havingpreciselythesametiming(frequencyandphase)InordertoenforcethistheTDMdeviceitselffrequentlyperformsthedigitizationanalogsignalsdigitalsignals