Definice
Internetová páteř: Internetová páteřní síť
Severalcomputersareconnected,andeachothercanseeotherpeople’sfiles.Thisiscalledalocalareanetwork,computersintheentirecityIftheyareallconnected,itisametropolitanareanetwork,andthenetworkthatconnectscitiesiscalledabackbonenetwork.ThesebackbonenetworksaretheInternetthatcanbedirectlyconnectedtoforeigncountriesapprovedbythestate.OtherISPs(InternetServiceProviders)withaccessfunctionshavetogothroughthesebackbonenetworksiftheywanttoconnectabroad.
Složení
"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.Čínská vzdělávací a výzkumná síť (CERNET)
❼.ChinaScienceandTechnology Network (CSTNET)
❽.ChinaGreatWallInternet(CGWNET)
❾．ChinaInternationalEconomicandTradeInternet (CIETNET)
Rozvoj
Přehled
Withtherapiddevelopmentofmoderntelecommunications,computerandInternettechnologies,data,voice,video,etc.Businesstransmissionsareconstantlyincreasingandareshowingatrendofconvergence.Theexistingnetworkhasbeenunabletomeettherapidlygrowingbusinessneeds.Thereisastrongneedtobuildanewtypeofbroadbandbackbonenetworktocarrytheserapidlydevelopingservices.
Fyzická vrstva
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 ,SONET se stal důležitou technologií přenosu páteřní sítě.Páteřní síť používá velký počet optických modulů SFP vyměnitelných za provozu.Optické moduly používají vysokou rychlost a dlouhou vzdálenost k řešení problémů upgradu a praktických aplikací.
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.
Síťová vrstva
Atthenetworklayer,withthegreatsuccessoftheInternet,IPhasbecomearecognizedstandard.Withthedevelopmentoftechnologyandthediversificationofbearerservices,IP,aconnectionlessprotocolthattransmitsdataina"best-effort"manner,needstoprovideservicequalityassurance(QoS)forthebusiness,otherwiseitwillnotbeabletomeettherequirementsofthebackbonenetwork.Carrier-classservicequality.
Při pohledu na úroveň sítě
Tímto způsobem, na úrovni sítě, páteřní síť sestávající z fyzické vrstvy, vrstvy datového propojení a síťové vrstvy tvoří architekturu IP/ATM/SONET/Optical.Zařízení SONET AP však přináší další"daňovou toleranci.
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.
Kvalita služeb
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.
Související rozdíly
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.