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1、Chapter5LinkLayerandLANsAnoteontheuseofthesepptslides:We’remakingtheseslidesfreelyavailabletoall(faculty,students,readers).They’reinPowerPointformsoyoucanadd,modify,anddeleteslides(includingthisone)andslidecontenttosuityourneeds.Theyobviouslyrepresentalotofworkonourpart.In
2、returnforuse,weonlyaskthefollowing:Ifyouusetheseslides(e.g.,inaclass)insubstantiallyunalteredform,thatyoumentiontheirsource(afterall,we’dlikepeopletouseourbook!)Ifyoupostanyslidesinsubstantiallyunalteredformonawwwsite,thatyounotethattheyareadaptedfrom(orperhapsidenticalto)o
3、urslides,andnoteourcopyrightofthismaterial.Thanksandenjoy!JFK/KWRAllmaterialcopyright1996-2007J.FKuroseandK.W.Ross,AllRightsReservedComputerNetworking:ATopDownApproach4thedition.JimKurose,KeithRossAddison-Wesley,July2007.15:DataLinkLayerChapter5:TheDataLinkLayerOurgoals:u
4、nderstandprinciplesbehinddatalinklayerservices:errordetection,correctionsharingabroadcastchannel:multipleaccesslinklayeraddressingreliabledatatransfer,flowcontrol:done!instantiationandimplementationofvariouslinklayertechnologies25:DataLinkLayerLinkLayer5.1Introductionandser
5、vices5.2Errordetectionandcorrection5.3Multipleaccessprotocols5.4Link-layerAddressing5.5Ethernet5.6Link-layerswitches5.7PPP5.8Linkvirtualization:ATM,MPLS35:DataLinkLayerLinkLayer:IntroductionSometerminology:hostsandroutersarenodescommunicationchannelsthatconnectadjacentnodes
6、alongcommunicationpatharelinkswiredlinkswirelesslinksLANslayer-2packetisaframe,encapsulatesdatagramdata-linklayerhasresponsibilityoftransferringdatagramfromonenodetoadjacentnodeoveralink45:DataLinkLayerLinklayer:contextdatagramtransferredbydifferentlinkprotocolsoverdifferen
7、tlinks:e.g.,Ethernetonfirstlink,framerelayonintermediatelinks,802.11onlastlinkeachlinkprotocolprovidesdifferentservicese.g.,mayormaynotproviderdtoverlinktransportationanalogytripfromPrincetontoLausannelimo:PrincetontoJFKplane:JFKtoGenevatrain:GenevatoLausannetourist=datagra
8、mtransportsegment=communicationlinktransportationmode=linklayerprotocoltravelagent