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兰州交通大学毕业设计（英文参考翻译）1OpticalfiberaccessnetworktechnologyTheentiretelecommunicationnetworkaccordingtonetworkfunctionisdividedintothreesections:switching,transmission,andaccess.Accesstotelecommunicationsbusinesstransparenttousers,transmitspecific,accesstolocalswitchandtheuserthattheconnectionbetweentheparts,usuallyincludesubscriberlinetransmissionsystem,reuseequipment,crossingconnectiondeviceoruser/networkterminalequipment.Andactuallypickforbusinessentityisbusinessnodes.1.Accessnetworkdevelopmentprocess1.1AccessNetwork(AN:Accessbybusiness)referstoanodeinterface(SNI)andrelatedusersNetworkinterface(UNI)betweenaseriesoftransmitentity(suchaslinefacilitiesandtransmissionfacilities)fortransmissionconsistingoftelecommunicationbusinessprovidetherequiredtransmitloadcapacity,implementationsystemconfigurationspercentilemanagementinterfaceviaandmanagement.Accesscanbeseenaswithbusinessandapplicationirrelevanttransmissionnetwork,mainlyfinishcrossingconnection,reuseandtransmissionfunction,itistransparenttousersofsignaling.Basedonmodernoftelecommunicationnetworkaccessnetworkisintegratedserviceaccess,simplelocalvoiceaccesswillbeincreasinglycannotmeettherequirements,thevoice,dataandimagecomprehensiveaccessisbecomingaccessnetworkdevelopmenttrend.Afteryearsofdevelopment,accessnetworkdefinethoughdoesnotchange,butitsconnotationandformshaschangedsignificantly.Superiortraditionalaccessnetworkintegratedopticalfiberaccessnetworkwillbeusersaccessthefuturedevelopingtrend.OpticalfiberaccessfromSNItoUNIreferstoallorpartoftheaccessnetworkbyusingopticalfiberasmedium.ITU-Taboutaccessnetworkrecommendationsindicatethatfiber,useraccesssystemiscomposedofthreeparts:opticallineterminal(OLT),opticaldistributionnetwork(ODN)andopticalnetworkunit(ONU).兰州交通大学毕业设计（英文参考翻译）21.2Accordingtotherequirementofsystemaccessframeworkandtheimportantcharacteristics,accessnetworkcanbesummarizedasthefollowing:1.2.1Accesstoaccessbusinessprovidesbearingcapacity,achievebusinesstransparenttransfer.1.2.2.Theaccessistransparenttouserssignaling,exceptforsomeuserssignalingformatconversionoutside,signalingandbusinessprocessingfunctionisstillinbusinessnode.1.2.3Theintroductionofshouldnotberestrictedaccessallkindsofexistingaccesstypesandbusiness,accessnetworkshouldthroughthelimitedstandardizationinterfaceandbusinessnodeconnected.1.2.4Accessnetworkhaveindependentfromthebusinessnodeinthenetworkmanagementsystem,thissystemthroughthestandardizedinterfacesconnectedTMN,accessnetworkoperationforimplementationTMN,maintenanceandmanagement.2.fiberstructure2.1generallinearstructure.Refertothepublicbus,fiberaseachuserterminalsthroughdirectconnectwithbuscouplernetworkstructure.Itscharacteristicissharingbackbonefiber,savelinestoremovenodeinvestment,thedemandishigher,dynamicrange,interferewitheachothereffectissmall.Defectislossofaccumulation,thebackbonefiberuseracceptancedependenceisstrong.2.2ringstructure.Referstoallshareafiberopticlinknode,fiberopticlinkitsendtoendtheclosedloopnetworkstructure.Characteristicisself-healing,namelycanberealizedwithoutintervention,thenetworkcanbeinarelativelyshortperiodoftimetorecoverfromfailurehavepreachedbusiness,highreliability.Defectishangedbythenumberofusersofmonocyliclimited,polycyclicinterchangeisrelativelycomplex,notsuitableforCATV,etcFenPeiXingbusiness.2.3starstructure.Thisstructureisactuallypoint-to-pointway,eachuserterminalsinthecentralnodethroughwithcontrolandswitchfunctionsoftheastralcouplersexchangeinformation.Characteristicsofsimplestructure,maintenanceisconvenient兰州交通大学毕业设计（英文参考翻译）3andeasytoupgradeandexpansionbetween,eachuserrelativelyindependent,goodsecrecy,businessadaptability.Defectishigher,networkingrequiredfibercostofpoorflexibility,highreliabilityrequirementsofcentralnode.2.4treestructure.Similartothebranches,ahierarchicalstructure,shapeintransferboxesandFenXianHeplaceadoptsmultipleopticaldistributor,willsignalfilteringdowntopendinningsallocation,havestrongcontrolcoordination.Characteristicissuitableforbroadcastingbusiness.Defectispowerlossisbigger,two-waycommunicationdifficultybigger.3．ThestatusofopticalaccessnetworkinthemoderncommunicationOpticalfiberinrealizingnationalinformationmodernizationaccessplaysamoreandmoreimportantrole,isanindispensablepartofmoderncommunicationsnetwork.Moderncommunicationsnetworkbasicrealizedbasedonfiberbackbonetransmissionandexchange,andaccesssectionisstillrestrictedmoderntelecommunicationsfurtherdevelopmentandimprovementofthebottleneck,therefore,toconstructionofnationalinformationinfrastructure(NII),accessnetworkisthekey.Accessnetworktechnologydevelopment,willresultingreatchangesoftelecommunicationsandinformationnetwork,namely,voice,data,video,etc.Variouskindsofinformationtransmission,comprehensivebusinesstogetherforimplementingtheresourcessharing,andgraduallyoptimizedcommunicationnetwork,greatlyimprovingnetworkbenefits.Twoopticalfiberopticaltransmissiontechnologyaccesswiththecombinationoftheaccesstechnology3.1LighttransmissiontechnologydevelopmentandevolutionSince1979,thehumanuseofopticalfiberascommunicationmode