wide area networking protocols

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1、WideAreaNetworkingProtocolsOverview1.0WideAreaNetworks2.0High-LevelData-LinkControlProtocol(HDLC)3.0Point-to-PointProtocol(PPP)4.0FrameRelay5.0IntegratedServicesDigitalNetwork6.0Dial-onDemandRouting(DDR)1.0WideAreaNetworks1.1IntroductiontoWideAreaServices1.2DefiningWANTerms1.2WANConnecti

2、onTypes1.3WANProtocols1.1IntroductiontoWideAreaServicesToextendLANstootherLANsatremotesitesConnectingsitestogethersoinformationcanbeexchangedServiceprovidersleaseorsharetheiralreadyinstalledconnections1.2DefiningWANTerms(WANServiceProviders)CustomerPremisesEquipment(CPE)Equipmentthatisow

3、nedandlocatedatthesubscriber’spremisesDemarcation(demarc)TheplacewheretheCPEendsandthelocalloopportionoftheservicebegins(usuallyinthe“phone-closet”)LocalLoopConnectsthedemarctotheclosestswitchingoffice(CO)CentralOffice(CO)/PointofPresence(POP)Connectsthecustomerstotheprovider’sswitchingn

4、etwork.TollNetworkTheswitchesandfacilities,(trunks),insidetheWANprovider’s“cloud”.SynchronousserialAsynchronousserial,ISDNSynchronousserial1.3WANConnectionTypesDedicatedLeasedlines(PointtoPointConnection)Apre-establishedWANcommunicationspathfromtheCPE,throughtheDCEswitch,totheCPEoftherem

5、otesite,allowingDTEnetworkstocommunicateatanytimewithnosetupproceduresbeforetransmittingdata.CircuitSwitchingSetsuplinelikeaphonecall.Nodatacantransferbeforetheend-to-endconnectionisestablished.Usedial-upmodemsandISDN.Itisusedforlow-bandwidthdatatransfers.PacketSwitchingSharebandwidthwit

6、hothercompaniestosavemoney.Fornotconstantlydatatransmission(otherwiseusingleasedline)TelephoneCompanyServiceProviderSpeedupto45MbpsLow-bandwidthdatatransfersSpeedrangefrom56Kto2.048M1.4WANProtocolsFrameRelayPacket-switchedtechnologywithDataLinkandPhysicalLayerspecificationProvideDynamic-

7、bandwidthallocationandcongestioncontrolISDN(IntegratedServicesDigitalNetwork)VoiceandDatatransmissionoverexistingphonelinesHigherspeedthananalogdial-uplink;goodchoiceasabackuplinkLAPB(LinkAccessProcedure,Balanced)Aconnection-orientedprotocolattheDataLinklayerforusewithX.2