Определение
Internetbackbone: Интернет опорна мрежа
Severalcomputersareconnected,andeachothercanseeotherpeople’sfiles.Thisiscalledalocalareanetwork,computersintheentirecityIftheyareallconnected,itisametropolitanareanetwork,andthenetworkthatconnectscitiesiscalledabackbonenetwork.ThesebackbonenetworksaretheInternetthatcanbedirectlyconnectedtoforeigncountriesapprovedbythestate.OtherISPs(InternetServiceProviders)withaccessfunctionshavetogothroughthesebackbonenetworksiftheywanttoconnectabroad.
Състав
"Backbonenetwork"isoftenusedtodescribethelarge-scalenetworkstructure.Todescribethenetworkstructure,itismainlytolookatthenetworktopology,notthespecificuse.Thetransmissionmethodorprotocol.Thebackbonenetworkisgenerallyawideareanetwork:therangeofactionistenstothousandsofkilometers.
Thebackbonenetworkiscomposedofmultipletransmissionmethodsandmultipleprotocolcombinations.
mycountryhas9majorbackbonenetworks:
❶.ChinaPublicComputerInternet(CHINANET)
❷.ChinaGoldenBridgeInformationNetwork(CHINAGBN)
❸．ChinaUnicomComputerInternet(UNINET)
❹.ChinaNetcomPublicInternet(CNCNET)
❺.ChinaMobileInternet(CMNET)
❻.ChinaEducationandResearchNetwork(CERNET)
❼.ChinaScienceandTechnologyNetwork(CSTNET)
❽.ChinaGreatWallInternet(CGWNET)
❾．ChinaInternationalEconomicandTradeInternet (CIETNET)
развитие
Преглед
Withtherapiddevelopmentofmoderntelecommunications,computerandInternettechnologies,data,voice,video,etc.Businesstransmissionsareconstantlyincreasingandareshowingatrendofconvergence.Theexistingnetworkhasbeenunabletomeettherapidlygrowingbusinessneeds.Thereisastrongneedtobuildanewtypeofbroadbandbackbonenetworktocarrytheserapidlydevelopingservices.
Физически слой
SONET(SynchronousOpticalNetwork)hasimportantvalueinmanyaspects,makingitthemostimportantprotocolforlong-distance,high-speedopticalfibercommunication.Firstofall,SONET'sscalabilitymakesittheprimarytechnologytorealizeanewroundofhigh-speedports.BecauseOC-3(155Mbps)hasbecomeanoutdatedauxiliarytechnology,OC-48(2.4Gbps)portspeedshavebecomeverycommononhigh-speedroutersandswitches,andOC-768(40Gbps)portspeedswillsoondebut.Asthethroughputrateofdatatrafficcontinuestoincrease ,SONEThasbecomeanimportantbackbonenetworktransmissiontechnology.ThebackbonenetworkusesalargenumberofSFPhot-swappableopticalmodules.Theopticalmodulesusehigh-speedandlong-distancetosolvetheupgradeandpracticalapplicationproblems.ShenzhenWeishengkangmainlyprovides155M~10Gopticalmodules,andthepackageincludes1*9,SFP,SFF,XFP,SFP+,X2,XENPARKandotheropticalmodules.
BeforetheemergenceofSONET,eachfiberopticequipmentmanufacturerworkedindependentlyanduseditsownindependenttechnologyinproductproduction,andtheproductswereincompatiblewitheachother.TheemergenceofSONEThasplayedaroleinstandardizinghigh-speedopticalfiberdatatransmission.
Datalinklayer
ATMcreatesasinglenetworkforvoice,videoanddata,andthevoiceandvideostreamscanbemaintainedatthelowlatencyandOnthejitterlevel.Atthesametime,time-insensitivedatacanmakefulluseoftheremainingchannelcapacity,whichcanrelativelyreducethecostofprovidingservicequalityassurance.
JustasSONEThasmanyfeaturesthatarenotincludedinthedefinitionoftraditionalphysicallayerprotocols,ATMcannotbecompletelyregardedasadatalinklayerprotocol.AlthoughanATMcellisverysimilartoatypicallayer2dataframe,haserrorcorrectioncapabilities,andalsocontainsaddressinformationthatisveryimportantforlocaldatalinks,thesecondlayerproceduresdonotrequirethesameasATM.Convertallcommunicationstreamsintofixed-lengthcells.
ATMhaselaborateservicequalityQoS,withoutthecompatibilityrequiredbythedatalinklayer.However,ATM,asaninterfacewiththephysicallayer,isundoubtedlyverysuitableforthedefinitionofthesecondlayerprotocol.ItsoptionsforthefirstlayerincludemanyopticalfibertransmissionmethodsfortransportingATMcells,includingSONET,Category5twistedpaircoppercables,andT1lines.
AlthoughATMcanalsobeusedasastatisticalmultiplexertoprovideservicesforalargenumberofnon-real-timedatastreams,itsmainadvantageliesintheabilitytoreceivereal-timedatastreams(suchasvoiceandvideo)andDoesnotcausejitteranddelay.
Мрежов слой
Atthenetworklayer,withthegreatsuccessoftheInternet,IPhasbecomearecognizedstandard.Withthedevelopmentoftechnologyandthediversificationofbearerservices,IP,aconnectionlessprotocolthattransmitsdataina"best-effort"manner,needstoprovideservicequalityassurance(QoS)forthebusiness,otherwiseitwillnotbeabletomeettherequirementsofthebackbonenetwork.Carrier-classservicequality.
Гледайки на ниво мрежа
Inthisway,atthenetworklevel,thebackbonenetworkconsistingofthephysicallayer,thedatalinklayerandthenetworklayerformsThearchitectureofIP/ATM/SONET/Optical.However,SONET'sAPSequipmentbringsanadditional"faulttolerancetax".Inordertoachievefaulttolerance,50%oftheentirebandwidthneedstobespentasa"faulttolerancetax"inSONET.Therefore,manytelecomoperatorswanttoremovethislayer.
TheshortcomingsoftheIP/ATM/SONET/Opticalarchitecturearegraduallyexposedwiththedeepeningoftheapplication:lowefficiency,complexequipment,highcost,complexmanagement,etc.AsthepacketforwardingspeedofgigabitroutingswitcheshasincreasedtoseveraltensofmegabytesandhasSONETportsof155Mbpsand622Mbps,theInternetbackbonenetworkisconstructedbyconnectingrouterswiththePPPprotocol.ThisisIPoverSONET(POS).structure.ThisstructuresoonreplacedATMasthemainstreamofInternetbackbonenetworktechnology.Itincreasedthetransmissionefficiencyfromlessthan80%tomorethan95%,andsimplifiedequipmentandreducedcosts.
IPoverSONETisnottheultimatesystemofhierarchicalsimplification.Inthebackbonenetwork,theSONETlayercanbefurthersimplified,andIPapplicationscanberundirectlyontheopticalchannel(IPoverOptical).Theall-opticalnetworkdoesnotrequirecomplicatedlinklayermanagementattheSONETlayer,andtheinherentdistributedsurvivalcharacteristicsoftheInternetmakeitcapableofprotectionandself-healing.SDHandATMarenotusedintheIP-optimizedopticalnetwork,andtheforwardingandswitchingofdatapacketsiscompletedbyagigabitroutingswitch.SincenolowerlayertransmissionprotocolcanbeusedintheIP-optimizedopticalnetwork,self-healingrecoveryisbestdoneatthenetworklayer.YoucanuseMPLS(Multi-ProtocolLabelSwitching)orDPT(DynamicPacketTransmission)torealizeself-healingrecoveryonthenetworklayertokeeptheentirenetworkrobustandefficient.
Качество на обслужване
ThenewgenerationofbroadbandIPbackbonenetworkisnolongertheInternetinthetraditionalsense.Itneedstorunmoreservicesonitsbackbone.Thenewbackbonenetworkstructuremustbeabletoprovidemultipleservicesincludingvoice,data,andvideo.Therefore,acertainqualityofservice(QoS)isrequired.Thisqualityofservicereferstotherequirementtoobtainhigh-qualityguaranteesintermsoftimedelayandtransmissionerrorrate.Inthenetwork,itmustbeabletoprovidethemeansofserviceflowcontrolandthemethodofflowmanagement.
Forbroadbandbackbonenetworks,thepursuitofmaximizingtheuseofresources,reducingcosts,andimprovingefficiencyarethefundamentalrequirementsfornetworkconstructionandnetworkoperations.Therefore,itisnecessarytochooseefficientnetworkingtechnologyatthehighlevelofthenetworktogivefullplaytophysicalresources.Trafficmanagementtechnologycanensurethequalityofserviceofeachbusinessinacongestednetwork.
IETFestablishedanewworkinggroupfromtheintegratedserviceengineeringgrouptocreateadifferentiatedservice(DiffServ)toimplementtheQoSfunctioninthebackbonenetwork.AnothereffectivemechanismforprioritizingtrafficinanIPnetworkisTCPratecontrol,whichisachievedbyadjustingthesizeoftheterminalwindowinsteadoflettingitgrowarbitrarily.TCPratecontrolcanreducepackettrafficonthenetwork.
AnimportantissueinIPbackbonenetworkmanagementishowtomonitortrafficandpreventandresolvecongestion.InordertoadapttothedevelopmentofIPoverATM,themulti-protocollabelswitchingtechnologyMPLShasemerged.MPLScanestablishavirtualcircuitforIPreal-timeservicedataflowbasedonthelabelintheATMswitchtoensureQoS.
Thefuturebroadbandbackbonenetworkwilltakeonthetaskofunifyingthethreenetworksandprovideasupportingplatformformultipleservices.Thenetworkmustfirsthavehighefficiency,makethenetworklevelmoreconcise,andthusobtainhightransmissionefficiency;inaddition,itisnecessarytoworkonthenetworklayerorahigherapplicationleveltoimprovethequalityofservice,trafficmonitoringandnetworkmanagementfunctionstoAhigherrealm.
Свързани разлики
Firstofall,theconceptofbackbonenetworkexistsinmanynetworks,suchasCPmetropolitanareanetwork,IPbearernetwork,etc.Theso-calledbackbonenetworkislocatedintheupperlayerofthenetworkstructure.Anetworkformedbytheconnectionofcorenetworkelementdevices.Secondly,inresponsetothisquestion,Iguesswhatthehostwantstoaskistherelationshipbetweenthecorenetworkandthebackbonenetworkofthebearernetwork.Eachprefecturecity(prefecturecity:city-levelcity)basicallyhasitsownlocalcorenetworkswitchroom,whichcompleteslocalandforeigncalltransferanddatatransmission.Ifyouwanttoexchangebusinesswithotherplaces,youneedtorelyonareliabletransmissionnetworktocompletethistask.Therefore,thisreliablenetworkprovidesan"interface"(actuallyadevice),andwecanintegratethecorenetworkThenetworkelementequipmentattheborderisconnectedtothe"interface"ofthereliabletransmissionnetwork,andthisinterfaceentersthebackbonenetworktocompletethetransmissiontaskwhenitgoesup.Simplyput,thebearernetworkistheStateGrid,andthecorenetworkisthenetworkofeachpowerstation.Tocompletetheoverallplanningofeachpowerstation,itmustbeconnectedtotheStateGrid.