SDH及其未來趨勢中英文對照外文翻譯文獻(xiàn)

SDH及其未來趨勢中英文對照外文翻譯文獻(xiàn)SDH及其未來趨勢中英文對照外文翻譯文獻(xiàn)(文檔含英文原文和中文翻譯)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及其未來趨勢n。Jyothirmai,r.ManasaValli。羅摩克里希納摘要——SDH規(guī)范了一個國際標(biāo)準(zhǔn)網(wǎng)絡(luò)的標(biāo)準(zhǔn)。它是同步的,所以名字的層次結(jié)構(gòu)是來自多路復(fù)用的方法。這個系統(tǒng)的進(jìn)化改善了數(shù)字網(wǎng)絡(luò)可操作性和可靠性，SDH演化符合客戶對不同的帶寬需求和不同的服務(wù)要求。SDH標(biāo)準(zhǔn)定義了傳輸速度發(fā)展到155.52mbps。在多路復(fù)用過程中載荷層在低階和高階虛擬容器,每一個包括一系列功能主管管理和錯誤監(jiān)控?？蚣芫哂幸粋€結(jié)構(gòu),有9段長度相等且每段STM-1擁有的信息結(jié)構(gòu)。SDH的靈活性可以通過引入網(wǎng)絡(luò)拓?fù)鋭?chuàng)造良好的優(yōu)勢。關(guān)鍵詞:SDH;多路復(fù)用;網(wǎng)路拓?fù)湟?引言1988年2月的協(xié)議是在CCITT達(dá)到了同步數(shù)字體系較單一的全球標(biāo)準(zhǔn)。用于運輸?shù)臄?shù)字信號，對于現(xiàn)有的PDH順利轉(zhuǎn)型也必須適應(yīng)三種不同的標(biāo)準(zhǔn)，同步一個二進(jìn)制主時鐘和所有的元素，層次設(shè)置比特率以分層順序同步與它數(shù)字信息。SDH定義了一組分層的結(jié)構(gòu)，標(biāo)準(zhǔn)以上物理傳輸網(wǎng)絡(luò)適當(dāng)?shù)剡m于有效載荷的傳輸。由于SDH的引入更廣泛，網(wǎng)絡(luò)的管理能力逐步因為全面的監(jiān)測和高能力的管理整個網(wǎng)絡(luò)增加。帶寬在幾秒鐘的時間尺度為具有開關(guān)功能，使SDH作為其傳輸機(jī)制等多路傳輸技術(shù)的控制。第一次嘗試制定光纖傳輸標(biāo)準(zhǔn)開始在美國為SONET（同步光網(wǎng)絡(luò)）這一標(biāo)準(zhǔn)的目的是通過允許來自不同廠商間的連接設(shè)備的擴(kuò)展的兼容性，簡化網(wǎng)絡(luò)運營商之間的互聯(lián)可以實現(xiàn)。SDH提供了傳輸網(wǎng)絡(luò)的具有高功能集無關(guān)的廠商和復(fù)雜的信號結(jié)構(gòu)。這導(dǎo)致了一個新的網(wǎng)絡(luò)應(yīng)用，新設(shè)備在新的網(wǎng)絡(luò)拓?fù)浣Y(jié)構(gòu)的部署和管理下，相比以前的傳輸網(wǎng)絡(luò)不同操作系統(tǒng)擁有更大的權(quán)力。手稿收到2012年11月Nanduri.Jyothirmai，電子和計算機(jī)工程KL大學(xué)。貢土爾，克里希納DT，印度安得拉邦。Rajanala.ManasaValli，電子和計算機(jī)工程。KLUniversity，貢土爾，克里希納DT，安得拉邦印度。A.拉瑪克里希納，電子和計算機(jī)工程。KLUniversity，貢土爾，克里希納DT，安得拉邦，印度。二.同步數(shù)字體系A(chǔ).SDH演進(jìn)優(yōu)點a）同步網(wǎng)絡(luò)：SDH的支持，其中異步網(wǎng)絡(luò)僅支持點對點的配置甚至點對多點配置。b）直接進(jìn)入低速支流，使不必要的需要復(fù)用/解復(fù)用整個高速信號。c）易于生長，較高的比特率提高了操作，管理，維護(hù)和配置功能。運送現(xiàn)有的PDH信號的步驟傳輸信號的進(jìn)化。d）能力。e）運輸未來的寬帶通道，使比特率更快。f）多廠商使用專有的非標(biāo)準(zhǔn)技術(shù)，用于傳輸光纖的信息只有這樣，才能為互連轉(zhuǎn)化為銅傳輸標(biāo)準(zhǔn)。g）提供網(wǎng)絡(luò)傳輸服務(wù)，如LAN到LAN（局域網(wǎng)），交互式多媒體，視頻會議。h）有增加光纖帶寬它給出了采用SDH更大的優(yōu)勢沒有限制。i）即使SDH的電路是非常復(fù)雜的，這是可能的，因為超大規(guī)模集成電路技術(shù)的電路。j）客戶相對于不同的帶寬需求的要求可以很容易地沒有額外的要求滿足。B.SDH的標(biāo)準(zhǔn)和原則SDH標(biāo)準(zhǔn)中規(guī)定為125微秒的持續(xù)時間的SDH的幀結(jié)構(gòu)，通過使用行矩陣以字節(jié)為單位所表示的音頻信號的采樣率的速度增加的比特數(shù)的增加和單線不足以顯示幀上的信息。該幀結(jié)構(gòu)包含9行和列的數(shù)目取決于同步傳輸模式（STM-1）有9行和270列。對于PDH信號中有125微秒的25個字節(jié)用于1.544Mbit是9行×3列同樣每秒信號2.048M位時，有一些額外的位都加上它擁有27車處和36字節(jié)在125微秒32個字節(jié)。STM-1幀結(jié)構(gòu)是其中的9行和270列9行9列容納段開銷9行×261columns容納有效載荷，其收容該主信息的STM-1的接口速度為155.52mbps.STM-0，它是1/3在STM-1幀是用來作為本基本rate.STM-0幀結(jié)構(gòu)是9行×90列的列9行×3列由段開銷，和9行×87列由有效載荷，接口速度在這個部分51.840每比特率。SDH原理涉及多個集裝箱。每個容器都有了頭，提供網(wǎng)絡(luò)管理功能的路徑。PDH信號的第一點是在該信號中制備的容器。在容器334.368Mbits在125微秒提高到756。在容器-4139.264M位信號增加9倍260字節(jié)容器從虛擬容器路徑開銷。在虛擬容器在頭上的路徑被組織在塊結(jié)構(gòu)的形式在125微秒。它包含在VC-1只有1個字節(jié)為125微秒的信息。在VC-3POH是9個字節(jié)1列。在9bytesVC-1的VC-4POH1列，VC-2的低階虛容器VC-3，VC-4高階虛容器。對于VC-1和支路單元2支路單元1是為VC-2和支路單元-3是VC-3，它被映射為VC-4支路組3.TU-3由3個字節(jié)出9個字節(jié)。這三者是H1，H2，H3and剩余的字節(jié)是固定的字節(jié)數(shù)的一個或多個支流中包含的支路單元group.AUG-2含有TU-1orTU-2TUG-3包含的信息是網(wǎng)絡(luò)節(jié)點的TUG-2s.The接口用于與另一節(jié)點進(jìn)行互連。指針定義了一個幀一個VC的相對于該幀的基準(zhǔn)偏移。傳輸實體AU是信息結(jié)構(gòu)的高階和多段層之間提供適配。它由信息凈負(fù)荷和AU指針指示的有效載荷幀的偏移量開始與復(fù)用段幀。八月含有均勻的AU-3或AU-4.Concatenation是其中所述多個虛擬容器是與彼此相關(guān)聯(lián)的程序。C.復(fù)用和段開銷多路復(fù)用技術(shù)可以處理從舞臺到舞臺的C-11被映射為C-12容器中的條目是2.048Mbit/sec。在C-2容器的入口6.312Mbps的。它是復(fù)用TUG-2也可以是4VC-11用VC-11或3VC-12TU-12TU-2，C-3容器需要輸入34Mbps的通過VC-3和withTU-3變到TUG-33NO的VC-3與AU-3可以直接轉(zhuǎn)到AUG和進(jìn)入STM幀同樣7TUG-2可以去一個TUG-3和3TUG被映射到一個VC-4.A139.264M比特/秒的信號可以通過C-4。VC-4被映射在一個VC-4與AU-4去AUG，然后到STM幀部分有過的STM-1幀的部分相關(guān)的字節(jié)可以知道，第4行9個字節(jié)是保留給非盟指針。STM-1幀儲量再生段開銷（RSOH）的前3rows.9列。從第5行到第9列被保留用于復(fù)用段開銷（MSOH）。1）A-1,A-2幀字節(jié)這些bits形成16位對齊字定義發(fā)送順序，參照每個信號速率。有在STM-1，3A-1字節(jié)和3的A-2STM-1。In高階的STM這個數(shù)字可能會隨STM順序字節(jié)。在STM-4會有12A-1個字節(jié)和12A-2個字節(jié)2）有一個單一的C-1字節(jié),用于標(biāo)識每間闊葉STM'S并在STM-N信號3）D-1或D-12該字節(jié)是數(shù)據(jù)通信在該D-1,D-2,D-3是用于再生部分D-4,D-12是用于復(fù)用段。4）E-1是再生段聯(lián)絡(luò)線,E-2是復(fù)用段階線。5）F-1被用于故障控制的目的。6）B-1個字節(jié)被稱為比特交錯奇偶校驗8，它是用于在再生段誤碼監(jiān)測。7）B-2字節(jié)這些都是在復(fù)用段用于錯誤監(jiān)控。8）K-1,K-2個字節(jié)用于在一組組織作為保護(hù)基團(tuán)的復(fù)用段的協(xié)調(diào)保護(hù)倒換。9）Z-1,Z-2所在的功能，但定義為每CCITT建議。復(fù)用D.SDH網(wǎng)元1）SDH再生器2）線路終端復(fù)用器3）分插復(fù)用器4）同步數(shù)字交叉連接系統(tǒng)（SDXC）1）線路終端MUXPDH網(wǎng)絡(luò)到SDH，它能接收一個數(shù)字輔助信號，并將它們復(fù)用為適當(dāng)?shù)墓鈱W(xué)SDH。輸入支流可以是現(xiàn)有PDH信號，如2,34和140mbps或較低速率的SDH信號。線路終端復(fù)用器需要輸入的范圍或2,34,140mbps和多路復(fù)用到較高速率的光載波。根據(jù)所要求的再生器間距均為1310nm和1550nm波長的光接口通?？勺鳛檫x擇，一個線路終端接口為內(nèi)部保護(hù)倒換。上線附加選項終端復(fù)用器設(shè)備提供訪問的順序線信道和數(shù)據(jù)通信頻道。線路終端多路復(fù)用器2)再生器再生器-再生器需要與間隔依賴于傳輸技術(shù)，這些不只是簡單的信號再生器，但有報告報警和性能監(jiān)控功能的故障可以快速分離的個別發(fā)送部在再生器中最基本的元素是當(dāng)傳輸是必要的50公里以上它們終止并重新生成光信號。1310nm和1550nm波長是首選，