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阅读使人充实，会谈使人敏捷，写作使人精确。——培根学问是异常珍贵的东西，从任何源泉吸收都不可耻。——阿卜·日·法拉兹Chapter1ComputerNetworksandtheInternet1.The(A)isaworldwidecomputernetwork,thatis,anetworkthatinterconnectsmillionsofcomputingdevicesthroughouttheworld.A.publicInternetB.IntranetC.switchnetD.televisionnet2.Whichkindofmediaisnotaguidedmedia?(D)A.twisted-paircopperwireB.acoaxialcableC.fiberopticsD.digitalsatellitechannel3.Whichkindofmediaisaguidedmedia?(C)A.geostationarysatelliteB.low-altitudesatelliteC.fiberopticsD.wirelessLAN4.Theunitsofdataexchangedbyalink-layerprotocolarecalled(A).A.FramesB.SegmentsC.DatagramsD.bitstreams5.Whichofthefollowingoptionbelongstothecircuit-switchednetworks?(D)A.FDMB.TDMC.VCnetworksD.bothAandB6.(B)makessurethatneithersideofaconnectionoverwhelmstheothersidebysendingtoomanypacketstoofast.A.ReliabledatatransferB.FlowcontrolC.CongestioncontrolD.Handshakingprocedure7.(A)meansthattheswitchmustreceivetheentirepacketbeforeitcanbegintotransmitthefirstbitofthepacketontotheoutboundlink.A.Store-and-forwardtransmissionB.FDMC.End-to-endconnectionD.TDM8.Datagramnetworksandvirtual-circuitnetworksdifferinthat(C).A.datagramnetworksarecircuit-switchednetworks,andvirtual-circuitnetworksarepacket-switchednetworks.阅读使人充实，会谈使人敏捷，写作使人精确。——培根学问是异常珍贵的东西，从任何源泉吸收都不可耻。——阿卜·日·法拉兹B.datagramnetworksarepacket-switchednetworks,andvirtual-circuitnetworksarecircuit-switchednetworks.C.datagramnetworksusedestinationaddressesandvirtual-circuitnetworksuseVC.numberstoforwardpacketstowardtheirdestination.D.datagramnetworksuseVC.numbersandvirtual-circuitnetworksusedestinationaddressestoforwardpacketstowardtheirdestination.9.Inthefollowingoptions,whichoneisnotaguidedmedia?(D)A.twisted-pairwireB.fiberopticsC.coaxialcableD.satellite10.Processingdelaydoesnotincludethetimeto(B).A.examinethepacket’sheaderB.waittotransmitthepacketontothelinkC.determinewheretodirectthepacketD.checkbit-errorinthepacket11.Inthefollowingfourdescriptions,whichoneiscorrect?(C)A.Thetrafficintensitymustbegreaterthan1.B.Thefractionoflostpacketsincreasesasthetrafficintensitydecreases.C.Ifthetrafficintensityisclosetozero,theaveragequeuingdelaywillbeclosetozero.D.Ifthetrafficintensityisclosetoone,theaveragequeuingdelaywillbeclosetoone.12.TheInternet’snetworklayerisresponsibleformovingnetwork-layerpacketsknownas(B)fromonehosttoanother.A.frameB.datagramC.segmentD.message13.Theprotocolsofvariouslayersarecalled(A).A.theprotocolstackB.TCP/IPC.ISPD.networkprotocol14.Therearetwoclassesofpacket-switchednetworks:(A)networksandvirtual-circuitnetworks.A.datagramB.circuit-switchedC.televisionD.telephone15.Accessnetworkscanbelooselyclassifiedintothreecategories:residentialaccess,companyaccessand(B)access.A.cabledB.wirelessC.campus阅读使人充实，会谈使人敏捷，写作使人精确。——培根学问是异常珍贵的东西，从任何源泉吸收都不可耻。——阿卜·日·法拉兹D.cityareaQuestion16～17Suppose,aistheaveragerateatwhichpacketsarriveatthequeue,Risthetransmissionrate,andallpacketsconsistofLbits,thenthetrafficintensityis(16:B),anditshouldnogreaterthan(17:B).16.A.LR／a17.A.2B.La／RB.1C.Ra／LC.0D.LR／aD.118.IntheInternet,theequivalentconcepttoendsystemsis(A).A.hostsB.serversC.clientsD.routers19.IntheInternet,endsystemsareconnectedtogetherby(C).A.copperwireB.coaxialcableC.communicationlinksD.fiberoptics20.EndsystemsaccesstotheInternetthroughits(C).A.modemsB.protocolsC.ISPD.sockets21.Endsystems,packetswitches,andotherpiecesoftheInternet,run(D)thatcontrolthesendingandreceivingofinformationwithintheInternet.A.programsB.processesC.applicationsD.protocols22.Therearemanyprivatenetworks,suchasmanycorporateandgovernmentnetworks,whosehostscannotexchangemessageswithhostsoutsideoftheprivatenetwork.Theseprivatenetworksareoftenreferredtoas(C).A.internetsB.LANC.intranetsD.WAN23.Theinternetallows(D)runningonitsendsystemstoexchangedatawitheachother.A.clientsapplicationsB.serverapplicationsC.P2PapplicationsD.distributedapplications24.TheInternetprovidestwoservicestoitsdistributedapplications:aconnectionless阅读使人充实，会谈使人敏捷，写作使人精确。——培根学问是异常珍贵的东西，从任何源泉吸收都不可耻。——阿卜·日·法拉兹unreliableserviceand(B)service.A.flowcontrolB.connection-orientedreliableC.congestioncontrolD.TCP25.Itdefinestheformatandtheorderofmessagesexchangedbetweentwoormorecommunicatingentities,aswellastheactionstakenonthetransmissionand/orreceiptofamessageorotherevent.Thesentencedescribes(B).A.InternetB.protocolC.intranetD.network26.Inthefollowingoptions,whichdoesnotdefineinprotocol?(D)A.theformatofmessagesexchangedbetweentwoormorecommunicatingentitiesB.theorderofmessagesexchangedbetweentwoormorecommunicatingentitiesC.theactionstakenonthetransmissionofamessageorothereventD.thetransmissionsignalsaredigitalsignalsoranalogsignals27.Inthefollowingoptions,whichisdefinedinprotocol?(A)A.theactionstakenonthetransmissionand/orreceiptofamessageorothereventB.theobjectsexchangedbetweencommunicatingentitiesC.thecontentintheexchangedmessagesD.thelocationofthehosts28.Inthefollowingoptions,whichdoesnotbelongtothenetworkedge?(B)A.endsystemsB.routersC.clientsD.servers29.Inthefollowingoptions,whichbelongstothenetworkcore?(B)A.endsystemsB.routersC.clientsD.servers30.Inthefollowingoptio