计算机网络英文题库(附答案)chapter1

******Chapter1ComputerNetworksandtheInternetnetworksuseVC.numberstoforwardpacketstowardtheir1．The()isaworldwidecomputernetwork,thatis,anetworkthaterconnectsmillionsofcomputingdevicesthroughouttheworld.DdatagramnetworksuseVC.numbersandvirtual-circuitnetworksppt3usedestinationaddressestoforwardpacketstowardtheirdestination.ApublicInternet9．Inthefollowingoptions,whichoneisnotaguidedmedia?()BIntranetAtwisted-pairwireCswitchnetBfiberopticsDtelevisionnetCcoaxialcable2．Whichkindofmediaisnotaguidedmedia?()DsatelliteAtwisted-paircopperwire10．Processingdelaydoesnotincludethetimeto().BacoaxialcableAexaminethepacketsheaderCfiberopticsBwaittotransmitthepacketontothelinkDdigitalsatellitechannelCdeterminewheretodirectthepacketDcheckbit-errorinthepacket3．Whichkindofmediaisaguidedmedia?()．Inthefollowingfourdescriptions,whichoneiscorrect?()AgeostationarysatelliteBlow-altitudesatelliteCfiberopticsDwirelessLANAThetrafficintensitymustbegreaterthan1.BThefractionoflostpacketsincreasesasthetrafficintensitydecreases.CIfthetrafficintensityisclosetozero,theaveragequeuingdelay4．Theunitsofdataexchangedbyalink-layerprotocolarecalled().willbeclosetozero.AFramesDIfthetrafficintensityisclosetoone,theaveragequeuingdelayBSegmentswillbeclosetoone.CDatagrams12．TheInternetsnetworklayerisresponsibleformovingnetwork-layerDbitstreamspacketsknownas()fromonehosttoanother.5．Whichofthefollowingoptionbelongstothecircuit-switchednetworks?Aframe()BdatagramAFDMCsegmentBTDMDmessageCVCnetworks13．Theprotocolsofvariouslayersarecalled().DbothAandBAtheprotocolstack6．()makessurethatneithersideofaconnectionoverwhelmstheotherBTCP/IPsidebysendingtoomanypacketstoofast.

CISPAReliabledatatransfer

DnetworkprotocolBFlowcontrol14．Therearetwoclassesofpacket-switchednetworks:()networksandCCongestioncontrol

virtual-circuitnetworks.DHandshakingprocedureAdatagram7．()meansthattheswitchmustreceivetheentirepacketbeforeitcanBcircuit-switchedbegintotransmitthefirstbitofthepacketontotheoutboundlink.CtelevisionAStore-and-forwardtransmissionBFDMDtelephoneCEnd-to-endconnection15．Accessnetworkscanbelooselyclassifiedintothreecategories:DTDMresidentialaccess,companyaccessand()access.8．Datagramnetworksandvirtual-circuitnetworksdifferinthat().AcabledAdatagramnetworksarecircuit-switchednetworks,and

Bwirelessvirtual-circuitnetworksarepacket-switchednetworks.Bdatagramnetworksarepacket-switchednetworks,andCcampusDcityareavirtual-circuitnetworksarecircuit-switchednetworks.Question16～17Cdatagramnetworksusedestinationaddressesandvirtual-circuit1DdistributedapplicationsSuppose,aistheaveragerateatwhichpacketsarriveatthequeue,Ris24．TheInternetprovidestwoservicestoitsdistributedapplications:athetransmissionrate,andallpacketsconsistofLbits,thenthetrafficintensityis(16),anditshouldnogreaterthan(17).connectionlessunreliableserviceand()service.Aflowcontrol16．ALR／aBconnection-orientedreliableBLa／RCcongestioncontrolC／LDTCP25．Itdefinestheformatandtheorderofmessagesexchangedbetweentwo

DLR／aormorecommunicatingentities,aswellastheactionstakenonthe17．A2B1transmissionand/orreceiptofamessageorotherevent.Thesentencedescribes().C0AInternetD-1Bprotocol18．IntheInternet,theequivalentconcepttoendsystemsis().CintranetAhostsDnetworkBservers26．Inthefollowingoptions,whichdoesnotdefineinprotocol?()CclientsAtheformatofmessagesexchangedbetweentwoormoreDrouterscommunicatingentities19．IntheInternet,endsystemsareconnectedtogetherby().BtheorderofmessagesexchangedbetweentwoormoreAcopperwirecommunicatingentitiesBcoaxialcableCtheactionstakenonthetransmissionofamessageorothereventCcommunicationlinksDthetransmissionsignalsaredigitalsignalsoranalogsignals模拟Dfiberoptics信号20．EndsystemsaccesstotheInternetthroughits().27．Inthefollowingoptions,whichisdefinedinprotocol?()AmodemsAtheactionstakenonthetransmissionand/orreceiptofamessageorBprotocols

othereventCISPBtheobjectsexchangedbetweencommunicatingentitiesDsocketsCthecontentintheexchangedmessages21．Endsystems,packetswitches,andotherpiecesoftheInternet,run()Dthelocationofthehoststhatcontrolthesendingandreceivingofinformationwithinthe28．Inthefollowingoptions,whichdoesnotbelongtothenetworkedge?Internet.

()AprogramsAendsystemsBprocesses

BroutersCapplications

CclientsDprotocols

Dservers22．Therearemanyprivatenetworks,suchasmanycorporateand

29．Inthefollowingoptions,whichbelongstothenetworkcore?()governmentnetworks,whosehostscannotexchangemessageswith

Aendsystemshostsoutsideoftheprivatenetwork.Theseprivatenetworksareoften

Broutersreferredtoas().

CclientsAinternets

DserversBLAN30．Inthefollowingoptions,whichisnotthebundledwiththeInternetsCintranetsconnection-orientedservice?()DWANAreliabledatatransfer23．Theinternetallows()runningonitsendsystemstoexchangedataBguaranteeofthetransmissiontimewitheachother.

CflowcontrolAclientsapplications

Dcongestion-controlBserverapplications31．AnapplicationcanrelyontheconnectiontodeliverallofitsdataCP2Papplicationswithouterrorandintheproperorder.Thesentencedescribes().2AflowcontrolCdataswitchingBcongestion-controlDmessageswitchingCreliabledatatransfer40．In()networks,theresourcesneededalongapathtoprovideforDconnection-orientedservicecommunicationbetweentheendsystemarereservedfortheduration持续ofthecommunicationsession.32．Itmakessurethatneithersideofaconnectionoverwhelms淹没压倒theothersidebysendingtoomanypacketstoofast.ThesentenceApacket-switcheddescribes().Bdata-switchedAflowcontrolCcircuit-switchedBcongestion-controlDmessage-switchedCconnection-orientedservice41．In()networks,theresourcesarenotreserved;asessionsmessagesDreliabledatatransferusetheresourcesondemand,andasaconsequence,mayhavetowait33．IthelpspreventtheInternetfromenteringastateofgridlock.Whenaforaccesstocommunicationlink.packetswitchbecomescongested,itsbufferscanoverflowandpacketApacket-switchedlosscanoccur.Thesentencedescribes().Bdata-switchedAflowcontrolCcircuit-switchedBcongestion-controlDmessage-switchedCconnection-orientedservice42．Inacircuit-switchednetwork,ifeachlinkhasncircuits,foreachlinkDreliabledatatransferusedbytheend-to-endconnection,theconnectiongets()ofthe34．TheInternetsconnection-orientedservicehasaname,itis().linksbandwidthforthedurationoftheconnection.ATCPAafraction1/nBUDPBallCTCP/IPC1/2DIPDntimes35．Inthefollowingoptions,whichservicedoesnotbeprovidedtoan43．For(),thetransmissionrateofacircuitisequaltotheframerateapplicationbyTCP?()multipliedbythenumberofbitsinaslot.AreliabletransportACDMABflowcontrolBpacket-switchednetworkCvideoconferencingCTDMDcongestioncontrolDFDM36．TheInternetsconnectionlessserviceiscalled().44．()meansthattheswitchmustreceivetheentirepacketbeforeitcanATCPbegintotransmitthefirstbitofthepacketontotheoutboundlink.BUDPAQueuingdelayCTCP/IPBStore-and-forwardtransmissionDIPCPacketloss37．Inthefollowingoptions,whichdoesnotuseTCP?()DPropagationASMTP45．ThenetworkthatforwardspacketsaccordingtohostdestinationBinternettelephoneaddressesiscalled()network.CFTPAcircuit-switchedDHTTPBpacket-switched38．Inthefollowingoptions,whichdoesnotuseUDP?()Cvirtual-circuitAInternetphoneDdatagramBvideoconferencing46．Thenetworkthatforwardspacketsaccordingtovirtual-circuitnumbersCstreamingmultimediaiscalled()network.DtelnetAcircuit-switched39．Therearetwofundamentalapproachestobuildinganetworkcore,()Bpacket-switchedandpacketswitching.Cvirtual-circuitAelectricalcurrentswitchingDdatagramBcircuitswitching347．Inthefollowingentries,whichisnotakindofaccessnetwork?()AresidentialaccessBcompanyaccessCwirelessaccessDlocalaccess48Supposethereisexactlyonepacketswitchbetweenasendinghostandareceivinghost.Thetransmissionratesbetweenthesendinghostandtheswitchandbetweentheswitchandthereceivinghostare1and2,respectively.Assumingthattheswitchusesstore-and-forwardpacketswitching,whatisthetotalend-to-enddelaytosendapacketoflengthL?(Ignorequeuingdelay,propagationdelay,andprocessingdelay.)()AL1＋R2BL1CL2Dnoneoftheabove49．Thetimerequiredtoexaminethepacketsheaderanddeterminewheretodirectthepacketispartofthe().AqueuingdelayBprocessingdelayCpropagationdelayDtransmissiondelay50Thetimerequiredtopropagatefromthebeginningofthelinktothenextrouteris().Aqueuingdel