SDH及其未来趋势中英文对照外文翻译文献

SDH及其未来趋势中英文对照外文翻译文献SDH及其未来趋势中英文对照外文翻译文献(文档含英文原文和中文翻译)SDHandItsFutureTrendsN.Jyothirmai,R.ManasaValli,A.RamaKrishnaAbstract–SDHpossessaninternationalstandardnetworkingprinciple.Itissynchronousbynaturesonameofthehierarchyistakenfrommultiplexingmethod.TheevolutionofthissystemimprovingtheeconomyofoperabilityandreliabilityofadigitalnetworkSDHevolutionmeetstherequirementofthecustomerwithrespecttothedifferentbandwidthrequirementsanddifferentservices.SDHstandarddefinesthetransmissionratedevelopedto155.52mbps.Inmultiplexingprocesspayloadsarelayeredintolowerorderandhigherordervirtualcontainer,eachincludingarangeofoverheadfunctionsformanagementanderrormonitoring.framehasarepeativestructureandconsistsofnineequallengthsegment.EachsegmentinSTM-1possesstheinformationstructure.TheflexibilityofSDHcanbeusedtobestadvantagebyintroducinganetworktopology.Keywords-CCITT:ComiteConsultifInternationaldeTelegraphiqueetTelephoniqueSTM:SynchronousTransportModuleADM:AddDropMultiplexerPOH:PathOverHeadSOH:SectionOverHeadI.INTRODUCTIONInFebruary1988anagreementwasreachedatCCITTforaSynchronousDigitalHierarchyrepresentingasingleworldwidestandard.Fortransportingthedigitalsignal.ForsmoothtransformationfromexistingPDHithastoaccommodatethreedifferentstandardsSYNCHRONOUS-OnemasterclockandallelementsynchronisewithitDIGITAL-Informationinbinary,HIERARCHY-setofbitsratesinahierarchicalorder.SDHdefinesasetofhierarchicalstructures,standardsforthetransportofsuitablyadaptedpayloadoverphysicaltransmissionnetworkAsSDHisintroducedmorewidely,themanagementcapabilityofnetworkgraduallyincreasesbecauseofthecomprehensivemonitoringandhighcapabilitymanagementthroughoutthenetwork.ThecontrolofbandwidthonatimescaleofsecondsforothermultiplexingtechniquesthathaveswitchingcapabilitiessoSDHastheirtransportmechanism.ThefirstattempttoformulatestandardsforopticaltransmissionstartedinU.S.AasSONET(SynchronousOpticalNetwork)TheaimofthisstandardswastosimplifyinterconnectionbetweennetworkoperatorsbyallowinginterconnectionofequipmentfromdifferentvendorstoextendthatcompatibilitycanbeachievedSDHhasprovidedtransmissionnetworkswithavendorindependentandsophisticatedsignalstructurethathasahighfeatureset.Theseresultedinanewnetworkapplications,thedeploymentofnewequipmentinnewnetworktopologies,andmanagementbydifferentoperationsystemofgreaterpowerfrompreviouslyseenintransmissionnetworkManuscriptreceivedonNovember,2012Nanduri.Jyothirmai,ElectronicsandComputerEngineeringK.L.University.Guntur,KrishnaDT,AndhraPradesh,India.Rajanala.ManasaValli,ElectronicsandComputerEngineeringK.L.University,Guntur,KrishnaDT,AndhraPradeshIndia.A.RamaKrishna,ElectronicsandComputerEngineering,K.L.University,Guntur,KrishnaDT,AndhraPradesh,India.II.SYNCHRONOUSDIGITALHIERARCHYDESCREPTIONMeritsofSDHEvolutiona)Synchronousnetworking:SDHsupportsevenmultipointConfigurationswhereasasynchronousnetworkingsupportsonlypointtopointconfigurations.b)Directaccesstolowerspeedtributaries,makesunnecessaryneedtomultiplex/demultiplextheentirehighspeedsignal.c)Easygrowthtohigherbitratesenhancesoperations,Administration,Maintenanceandprovisioningcapabilities.d)CapabilityoftransportingexistingPDHsignalstepstoevolutionoftransmissionsignalse)Transportingfuturebroadbandchannelmakesbitratefaster.f)Multivendorsuseproprietarynonstandardtechniquesfortransportinginformationonfibreonlywaytointerconnectwasconverttocoppertransmissionstandards.g)ItprovidesNetworktransportserviceslikeLANtoLAN(localareanetwork)Interactivemultimedia,videoconferencing.h)ThereisnolimitinincreasingtheopticalfibrebandwidthitgivesagreateradvantageinusingSDH.i)EventhoughSDHcircuitryishighlycomplicated,itispossibletohavecircuitrybecauseofVLSItechnique.j)Therequirementofcustomerswithrespecttodifferentbandwidthrequirementscouldbeeasilymeetwithoutadditionalrequirements.B.SDHStandardsAndPrinciplesSDHstandardprovidessamplingratesofaudiosignalas125microsecondsdurationtheframestructureofSDHisrepresentedbyusingmatrixofrowsinbyteunitsAsthespeedincreasesthenumberofbitsincreasesandthesinglelineisinsufficienttoshowtheinformationontheframe.Theframestructurecontains9rowsandnumberofcolumnsdependingonthesynchronoustransfermode(STM-1)thereare9rowsand270columns.ForPDHsignalthereare25bytesin125microsecondfor1.544Mbitwhichis9rowsx3columnssimilarlyfor2.048Mbitspersecondsignalthereare32bytesin125microsecondswhensomeadditionalbitsareaddeditholds27bysand36bytesSTM-1framestructureis9rowsand270columnsamongthem9rowsand9columnsaccommodatesectionoverhead9rowsx261columnsaccommodatepayloadwhichaccommodatesthemaininformationTheinterfacespeedofSTM-1is155.52mbps.STM-0whichis1/3oftheSTM-1frameisusedAsthepresentbasicrate.STM-0framestructureis9rowsx90columnsoutof9rowsx3columnsconsistsofsectionoverhead,and9rowsx87columnsconsistsofpayload.Theinterfacespeedis51.840perbitrateacrossthissectionPrinciplesofSDHinvolveanumberofcontainers.Eachcontainerhasapathoverheadwhichprovidesnetworkmanagementcapabilities.ThefirstpointofPDHsignalisthecontainerinwhichthesignalisprepared.Incontainer-334.368Mbitsincreasedto756in125microsecond.Incontainer-4139.264Mbitssignalisincreasedto9x260bytescontainerwithpathoverheadfromavirtualcontainerInvirtualcontainerthepathoverheadisorganisedintheformofblockstructurein125microseconds.Itcontainsinformationofonly1byteinVC-1for125microseconds.InVC-3POHis1columnof9bytes.InVC-4POH1columnof9bytesVC-1,VC-2arelowerordervirtualcontainerVC-3,VC-4arehigherordervirtualcontainer.Tributaryunit1forVC-1andtributaryunit2isforVC-2andtributaryunit-3isforVC-3whichismappedforVC-4tributarygroup-3.TU-3consistsof3bytesoutof9bytes.ThesethreeareH1,H2,H3andremainingbytesarefixedbytesoneormoretributariesarecontainedintributaryunitgroup.AUG-2containsTU-1orTU-2TUG-3containsTUG-2s.Theinterfaceofanetworknodewhichisusedtointerconnectwithanothernode.PointerdefinesaframeoffsetofaVCwithrespecttotheframereferenceofTransportentity.AUistheinformationstructurewhichprovidesadaptationbetweenhigherorderandmultiplexersectionlayer.itconsistsofinformationpayloadandaAUpointerwhichindicatestheoffsetofthepayloadframestartrelatingtothemultiplexsectionframe.AUGcontainsahomogenousofAU-3orAU-4.ConcatenationisaprocedurewhichthemultiplevirtualcontainerareassociatedwithoneanotherC.MultiplexingAndSectionOverheadMultiplexingtechniquescanbeprocessfromstagetostageC-11ismappedwithC-12containerwheretheentryis2.048Mbit/sec.InC-2containertheentry6.312mbps.ItismultiplexedwithTUG-2itcaneitherbe4VC-11withVC-11or3VC-12withTU-12withTU-2.TheC-3containertakestheinput34MbpsthroughVC-3andwithTU-3goestoTUG-33No’s.VC-3withAU-3candirectlygoestotheAUGandenterSTMframesimilarly7TUG-2cangotooneTUG-3and3TUGaremappedintooneVC-4.A139.264Mbits/secsignalcanbemappedintooneVC-4throughC-4.VC-4withAU-4goestoAUGandthentoSTMframeSectionoverhadportionoftheSTM-1framewiththerelevantbytesitcanbeknownthat4throw9bytesarereservedforAUpointers.Thetop3rows.9columnsofSTM-1framereservesforRegenerationSectionOverhead(RSOH).From5throwto9thcolumnarereservedforMultiplexingSectionOverhead(MSOH)1)A-1,A-2areframingbytesthesebitsform16bitalignmentworddefinesthetransmittersequencewithreferencetoeachsignalrates.Thereare3A-1bytesinSTM-1and3A-2bytesinSTM-1.InhigherorderSTMthisnumbersmayincreaseswithSTMorder.InSTM-4therewillbe12A-1bytesand12A-2bytes2)ThereisasingleC-1bytewhichisusedtoidentifyeachofinter-leavedSTM’SandinanSTM-Nsignal3)D-1orD-12ThisbytesarefordatacommunicationInthisD-1,D-2,D-3areforRegenerationSectionD-4toD-12areforMultiplexSection4)E-1isforregeneratorsectionorderwire,E-2isformultiplexsectionorderwire5)F-1isusedforfaultcontrolpurposes6)B-1bytearecalledbitinterleavedparity-8whichisusedforerrormonitoringintheregenerationsection7)B-2bytestheseareusedforerrormonitoringinthemultiplexsection8)K-1,K-2bytesareusedforcoordinatingtheprotectionswitchingacrossasetofmultiplexsectionorganisedasprotectiongroup9)Z-1,Z-2arelocatedforfunctionsandyetdefinedasperCCITTrecommendationsMultiplexingD.SDHNetworkElements1)SDHregenerator2)LineTerminalMultiplexer3)AddDropMultiplexer4)SynchronousDigitalCrossConnectSystems(SDXC)1)LINETERMINALMUXPDHnetworktotheSDH.ItcanacceptanumberoftributarysignalsandmultiplexthemtotheappropriateopticalSDH.TheinputtributariescaneitherbeexistingPDHsignalssuchas2,34and140mbpsorlowerrateSDHsignalsThelineterminalmultiplexertakestherangeofinputeither2,34,140,mbpsandmultiplextothehigherrateopticalcarrier.Dependingontherequiredregeneratorspacing,opticalinterfacesofboth1310nmand1550nmaregenerallyavailableastheoption,alineterminalinterfaceforinternalprotectionswitching.AdditionaloptiononlineTerminalMultiplexerequipmentprovideforaccesstotheorderwirechannelandthedatacommunicationchannels.LineTerminalMux2)REGENERATORRegenerator-RegeneratorsarerequiredwithspacingdependentonthetransmissiontechnologythesearenotjustsimplesignalsregeneratorsbuthavealarmreportingandperformancemonitoringcapabilityafaultcanbequicklyisolatedtotheindividualtransmissionsectionThemostbasicelementintheregeneratoriswhenthetransmissionisneededmorethan50kmtheyterminateandregeneratetheopticalsignal.wavelengthsof1310nmand1550nmarepreferredbecauseglassfibreispeculiartransparenttolightatthesewavelengthfibreisevenmoretransparentat1550nthan1310andsolowerregeneratorsareneededthefurtherthesignalhastogothegreaterthetransmitterpowerandthemostsensitivereceivershavetobe.CertainstandardsdefinetransmittedopticalpowerandthereceiversensitivityforeachtypeofsystemRegenerator3)ADD/DROPMUXAddDropMultiplexer(ADM):ADM’SaregenerallyavailableattheSTM-1andSTM-4interfaceratesandsignalswithinADM;itispossibletoaddchannelsto,ordropchannelsfromthethroughsignal.TheADMfunctionistheoneofthemajoradvantagesresultingfromtheSDHwherethePDHnetworkrequiresbanksofhardwiredback-backterminalsAdd/DropMuxisanetworkelementwhichallowsconfigurableofasubnetofapayloadfromahigherratedatastream.ItisthebasicSDHbuildingblockforlocalaccesstosynchronousnetworks.itgenerallyoffersSTM-1interfacesandoperatesinthethru-modefashion.Awidevarietyoftributarysignals,suchas2mbpscanbeadded.ThiscapabilityisoneofthekeybenefitsprovidedbysynchronoussystemssinceADMelementssupportsafunctionthepreviouslytookbankstoback-backequipment.Incontrastwithnormalmultiplexerinwhichahighspeedsignalmustbecompletelydemultiplextosomeintermediatestage,attheminimumbeforeaccesstotheportionofsignalcanbeachievedonADD/DROPMultiplexerallowaccesstothehighspeedsignaldirectlyandselecttrafficchannels.Accessprovidedto2.048MbpschannelsormixofthemTMAdd/DropMux.4)SYNCHRONOUSDXCSynchronousDigitalCrossConnectfunctionasasemi-permanentswitchesfortransmissionchannelsandcanswitchatanylevelfrom64kbpsuptoSTM-1.DXCcanberapidlyreconfiguredundersoftwarecontroltoprovidedigitalleasedlinesandotherservicesofvaryingbandwidth.Itiscapabilitywithoutneedfordemultiplexingmakesthedigitalcrossconnectsuchapowerfultool,allowingrapidconfigurationofthetransportnetworktoprovidedigitalleasedlinesandotherservices.ThesynchronousDXCfunctionsasasemi-permanentswitchforvaryingbandwidthtransmissionchannelsi.e.2Mbpsundersoftwarecontrol,thecrossconnectdevicescanpickoutandrerouteoneormorelowerorderchannelsfromtransmissionsignalswithouttheneedofdemultiplexing.TheDXCdevicewillbeusedextensivelytoreplacethedigitaldistributionframeswhichareusedinpresentdaydigitalexchanges.Thiswilleliminatethenetworkproblemsthatresultsfromfaultsinthewiringandrewiringofdigitaldistributionframes.DXCdevicesareclassifiedintermsoftheirlineinterfaceandswitchinglevel,i.e.aDXCwillhavetheinterfacesatSTM-1andswitchattheSTM-1levelwhereasacrossconnectatthe64Kbpschannellevel.SynchronousDXCE.NETWORKTOPOLOGY1)Point-Pointlink2)Ringtopology3)Startopology4)MeshtopologyInitiallySDHtechnologywillbedeployedinnewinstallationsandthentoreplaceorupgradeexistingsystemswhentheyreachmaximumcapacityAtthesimplestlevelnewpoint-pointsystemswilluseSDHterminalmuxeswilltheabilitytoexpandtomoretomorecomplexSDHconstructionslaterwewillnowexamineeachpossibletopologyinturn.Havingidentifiedandexplainthecurrentsetofnetworkbuildingblocks,wewillnowlookatthevariousatthevariousmethodsofconstructingSDHnetworksinpractice.1)POINT-POINTLINKSDHlinesystemsarenaturalsuccessor’slinesystemscurrentlydeployedinbackbonenetworks.InnewinstallationsthesePDHcapacitieswillcommonlybereplacedbySTM-4linesystems.SinceSDHsystemswillbegantoappearinspecificroutesoroverlaynetworkswithintheexistingtransmissionnetworks,thiswillhavetocoverthewholetransmissionnetworkincludingbothSDHandPDHpartstheprotectioncanbegivenwiththestandbylineforfailureagainstfibre.PayloadcanbeanyofthePDHrateorSDHlinelowerrate.2)RINGTOPOLOGYRingisalinearnetworkloopedbacktoitself.Ringnetworkisselfhealingtypereroutingortrafficwhenalinkfailsthesimplefailstopologyofaringfacilitatestheimplementationofprotocolsthatcandetectthefailureofafibresegmentofnodeandre-establishcommunicationtypicallyintimeframesontheorderofmilliseconds3)STARTOPOLOGYTrafficpassesthruacentralnodecalledHUBwherehubisaDXCifitfailstrafficfails4)MESHTOPOLOGYThemeshtopologyallowseventhemostparanoidnetworkmanagetohaveagoodcomfortbecauseoftheflexibilityandredundancythatitgives5)LINEARBUSTOPOLOGYThelinearbustopologyisusedwhenthereisnecessaryforprotectionandhasgreatnetworkflexibility.III.FUTURESDHNextgenerationSDHenablesoperatorstoprovidemoredatatransportserviceswhileincreasingtheefficiencyofinstalledSDHbyaddingthenewedgenodeswhichisknownasMultiserviceprovisioningplatformswhichcanoffersacombinationofdatainterfaces.SuchasEthernet,MultiProtocolLabelSwitching(MPLS)orResilientPacketRing(RPR)WithoutremovingthosefromSDHAlmostallnewfibretransmissionsystemsnowbeinginstalledinpublicnetworksTomeetthisrequirementsequipmentvendorsknowthattheydofarmorethansimpleboltpacketdatainterfacesontotheoutsideofaSDHinsteadtheyhavedevelopedsystemsthatspanfromcustomerstocore,multiprotocoltrafficadaption,servicemultiplexingandend-endoperationsmanagements.SDHisnolongerspokenas“LegacySDH”somethingtobereplacedinthenextbigthingandthatforatleastnextdecadeitrepresentfutureoftelecommunicationButtodeliveronthefutureequipmentmanufacturemustevolvetheirequipmentthatitconformstotheneedsoftheworld’slargestoperatorsandthosecarriersaresettingthebarhigh,demandaffordsstandardbasedplatformsthatarestandardscompactandyethighlyscalableandtheydeliverpacketsandTDMservicesbothseamlesslyandwithoutmanualconfiguration.IV.CONCLUSIONWithintroductionofSDHsolutiontosomeoftheproblemslikeUniversalstandardhierarchy,transportingfuturebroadbandsignal,increasingofopticalfibrebandwidth,operatinginthemultivendorenvironment.SDHisveryrobustandreliablecontainingbuilt-in-mechanismtoprovide99.9percentnetworkavailability.EventhoughitsolvesthemajorissuesstillsomedisadvantagesareexistinginSDHsofurthermoretheseproblemscanbesolvedbynextgenerationSDH.AsNGSDHprovideseconomical,technologicalfeasiblesolutionfortransmittingbothvoiceanddataovercarriernetworkNGSDHhavetheflexibilitytomanagethebandwidthortheabilitytoquicklyprovisionservicesandensurenetworkscalabilityandoperationalefficiency.REFERENCES[1]ETS300304“TransmissionandMultiplexing(TM);SynchronousDigitalHierarchy(SDH)InformationModelforNetworkElement(NE)view”.[2]ITU-TRecommendationM.3100”GenericNetworkInformationModel”.[3]EN300417-3-1“TransmissionandMultiplexing(TM);GenericRequirementsoftransportfunctionalityofequipment,part3-1,SynchronousTransportModule(STM-N)RegeneratorandMultiplexSectionLayerfunctions”.[4]ITU-TRecommendationG.702DigitalHierarchyBitRatesSDH及其未来趋势n。Jyothirmai,r.ManasaValli。罗摩克里希纳摘要——SDH规范了一个国际标准网络的标准。它是同步的,所以名字的层次结构是来自多路复用的方法。这个系统的进化改善了数字网络可操作性和可靠性，SDH演化符合客户对不同的带宽需求和不同的服务要求。SDH标准定义了传输速度发展到155.52mbps。在多路复用过程中载荷层在低阶和高阶虚拟容器,每一个包括一系列功能主管管理和错误监控。框架具有一个结构,有9段长度相等且每段STM-1拥有的信息结构。SDH的灵活性可以通过引入网络拓扑创造良好的优势。关键词:SDH;多路复用;网路拓扑一.引言1988年2月的协议是在CCITT达到了同步数字体系较单一的全球标准。用于运输的数字信号，对于现有的PDH顺利转型也必须适应三种不同的标准，同步一个二进制主时钟和所有的元素，层次设置比特率以分层顺序同步与它数字信息。SDH定义了一组分层的结构，标准以上物理传输网络适当地适于有效载荷的传输。由于SDH的引入更广泛，网络的管理能力逐步因为全面的监测和高能力的管理整个网络增加。带宽在几秒钟的时间尺度为具有开关功能，使SDH作为其传输机制等多路传输技术的控制。第一次尝试制定光纤传输标准开始在美国为SONET（同步光网络）这一标准的目的是通过允许来自不同厂商间的连接设备的扩展的兼容性，简化网络运营商之间的互联可以实现。SDH提供了传输网络的具有高功能集无关的厂商和复杂的信号结构。这导致了一个新的网络应用，新设备在新的网络拓扑结构的部署和管理下，相比以前的传输网络不同操作系统拥有更大的权力。手稿收到2012年11月Nanduri.Jyothirmai，电子和计算机工程KL大学。贡土尔，克里希纳DT，印度安得拉邦。Rajanala.ManasaValli，电子和计算机工程。KLUniversity，贡土尔，克里希纳DT，安得拉邦印度。A.拉玛克里希纳，电子和计算机工程。KLUniversity，贡土尔，克里希纳DT，安得拉邦，印度。二.同步数字体系A.SDH演进优点a）同步网络：SDH的支持，其中异步网络仅支持点对点的配置甚至点对多点配置。b）直接进入低速支流，使不必要的需要复用/解复用整个高速信号。c）易于生长，较高的比特率提高了操作，管理，维护和配置功能。运送现有的PDH信号的步骤传输信号的进化。d）能力。e）运输未来的宽带通道，使比特率更快。f）多厂商使用专有的非标准技术，用于传输光纤的信息只有这样，才能为互连转化为铜传输标准。g）提供网络传输服务，如LAN到LAN（局域网），交互式多媒体，视频会议。h）有增加光纤带宽它给出了采用SDH更大的优势没有限制。i）即使SDH的电路是非常复杂的，这是可能的，因为超大规模集成电路技术的电路。j）客户相对于不同的带宽需求的要求可以很容易地没有额外的要求满足。B.SDH的标准和原则SDH标准中规定为125微秒的持续时间的SDH的帧结构，通过使用行矩阵以字节为单位所表示的音频信号的采样率的速度增加的比特数的增加和单线不足以显示帧上的信息。该帧结构包含9行和列的数目取决于同步传输模式（STM-1）有9行和270列。对于PDH信号中有125微秒的25个字节用于1.544Mbit是9行×3列同样每秒信号2.048M位时，有一些额外的位都加上它拥有27车处和36字节在125微秒32个字节。STM-1帧结构是其中的9行和270列9行9列容纳段开销9行×261columns容纳有效载荷，其收容该主信息的STM-1的接口速度为155.52mbps.STM-0，它是1/3在STM-1帧是用来作为本基本rate.STM-0帧结构是9行×90列的列9行×3列由段开销，和9行×87列由有效载荷，接口速度在这个部分51.840每比特率。SDH原理涉及多个集装箱。每个容器都有了头，提供网络管理功能的路径。PDH信号的第一点是在该信号中制备的容器。在容器334.368Mbits在125微秒提高到756。在容器-4139.264M位信号增加9倍260字节容器从虚拟容器路径开销。在虚拟容器在头上的路径被组织在块结构的形式在125微秒。它包含在VC-1只有1个字节为125微秒的信息。在VC-3POH是9个字节1列。在9bytesVC-1的VC-4POH1列，VC-2的低阶虚容器VC-3，VC-4高阶虚容器。对于VC-1和支路单元2支路单元1是为VC-2和支路单元-3是VC-3，它被映射为VC-4支路组3.TU-3由3个字节出9个字节。这三者是H1，H2，H3and剩余的字节是固定的字节数的一个或多个支流中包含的支路单元group.AUG-2含有TU-1orTU-2TUG-3包含的信息是网络节点的TUG-2s.The接口用于与另一节点进行互连。指针定义了一个帧一个VC的相对于该帧的基准偏移。传输实体AU是信息结构的高阶和多段层之间提供适配。它由信息净负荷和AU指针指示的有效载荷帧的偏移量开始与复用段帧。八月含有均匀的AU-3或AU-4.Concatenation是其中所述多个虚拟容器是与彼此相关联的程序。C.复用和段开销多路复用技术可以处理从舞台到舞台的C-11被映射为C-12容器中的条目是2.048Mbit/sec。在C-2容器的入口6.312Mbps的。它是复用TUG-2也可以是4VC-11用VC-11或3VC-12TU-12TU-2，C-3容器需要输入34Mbps的通过VC-3和withTU-3变到TUG-33NO的VC-3与AU-3可以直接转到AUG和进入STM帧同样7TUG-2可以去一个TUG-3和3TUG被映射到一个VC-4.A139.264M比特/秒的信号可以通过C-4。VC-4被映射在一个VC-4与AU-4去AUG，然后到STM帧部分有过的STM-1帧的部分相关的字节可以知道，第4行9个字节是保留给非盟指针。STM-1帧储量再生段开销（RSOH）的前3rows.9列。从第5行到第9列被保留用于复用段开销（MSOH）。1）A-1,A-2帧字节这些bits形成16位对齐字定义发送顺序，参照每个信号速率。有在STM-1，3A-1字节和3的A-2STM-1。In高阶的STM这个数字可能会随STM顺序字节。在STM-4会有12A-1个字节和12A-2个字节2）有一个单一的C-1字节,用于标识每间阔叶STM'S并在STM-N信号3）D-1或D-12该字节是数据通信在该D-1,D-2,D-3是用于再生部分D-4,D-12是用于复用段。4）E-1是再生段联络线,E-2是复用段阶线。5）F-1被用于故障控制的目的。6）B-1个字节被称为比特交错奇偶校验8，它是用于在再生段误码监测。7）B-2字节这些都是在复用段用于错误监控。8）K-1,K-2个字节用于在一组组织作为保护基团的复用段的协调保护倒换。9）Z-1,Z-2所在的功能，但定义为每CCITT建议。复用D.SDH网元1）SDH再生器2）线路终端复用器3）分插复用器4）同步数字交叉连接系统（SDXC）1）线路终端MUXPDH网络到SDH，它能接收一个数字辅助信号，并将它们复用为适当的光学SDH。输入支流可以是现有PDH信号，如2,34和140mbps或较低速率的SDH信号。线路终端复用器需要输入的范围或2,34,140mbps和多路复用到较高速率的光载波。根据所要求的再生器间距均为1310nm和1550nm波长的光接口通常可作为选择，一个线路终端接口为内部保护倒换。上线附加选项终端复用器设备提供访问的顺序线信道和数据通信频道。线路终端多路复用器2)再生器再生器-再生器需要与间隔依赖于传输技术，这些不只是简单的信号再生器，但有报告报警和性能监控功能的故障可以快速分离的个别发送部在再生器中最基本的元素是当传输是必要的50公里以上它们终止并重新生成光信号。1310nm和1550nm波长是首选，