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1、、英文原文OpticalfiberaccessnetworktechnologyDuringtheearly1980s,analogcellulartelephonesystemswereexperiencingrapidgrowthinEurope,particularlyinScandinaviaandtheUnitedKingdom,butalsoinFranceandGermany.Eachcountrydevelopeditsownsystem,whichwasincompatible.Theentiretelecommunicationnetworkaccordingtonetwo
2、rkfunctionisdividedintothreesections:switching,transmission,andaccess.Accesstotelecommunicationsbusinesstransparenttousers,transmitspecific,accesstolocalswitchandtheuserthattheconnectionbetweentheparts,usuallyincludesubscriberlinetransmissionsystem,reuseequipment,crossingconnectiondeviceoruser/netwo
3、rkterminalequipment.Andactuallypickforbusinessentityisbusinessnodes.1.Accessnetworkdevelopmentprocess1.1AccessNetwork(AN:Accessbybusiness)referstoanodeinterface(SNI)andrelatedusersNetworkinterface(UNI)betweenaseriesoftransmitentity(suchaslinefacilitiesandtransmissionfacilities)fortransmissionconsist
4、ingoftelecommunicationbusinessprovidetherequiredtransmitloadcapacity,implementationsystemconfigurationspercentilemanagementinterfaceviaandmanagement.Accesscanbeseenaswithbusinessandapplicationirrelevanttransmissionnetwork,mainlyfinishcrossingconnection,reuseandtransmissionfunction,itistransparenttou
5、sersofsignaling.Basedonmodernoftelecommunicationnetworkaccessnetworkisintegratedserviceaccess,simplelocalvoiceaccesswillbeincreasinglycannotmeettherequirements,thevoice,dataandimagecomprehensiveaccessisbecomingaccessnetworkdevelopmenttrend.Afteryearsofdevelopment,accessnetworkdefinethoughdoesnotchan
6、ge,butitsconnotationandformshaschangedsignificantly.Superiortraditionalaccessnetworkintegratedopticalfiberaccessnetworkwillbeusersaccessthefuturedevelopingtrend.OpticalfiberaccessfromSNItoUNIreferstoallorpartoftheaccessnetworkbyusingopticalfiberasmedium.ITU-Taboutaccessnetworkrecommendationsindicate
7、thatfiber,useraccesssystemiscomposedofthreeparts:opticallineterminal(OLT),opticaldistributionnetwork(ODN)andopticalnetworkunit(ONU).1.2Accordingtotherequirementofsystemaccessframeworkandtheimportantch