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1Chapter1ComputerNetworksandtheInternet1．The()isaworldwidecomputernetwork,thatis,anetworkthatinterconnectsmillionsofcomputingdevicesthroughouttheworld.ppt3ApublicInternetBIntranetCswitchnetDtelevisionnet2．Whichkindofmediaisnotaguidedmedia?()Atwisted-paircopperwireBacoaxialcableCfiberopticsDdigitalsatellitechannel3．Whichkindofmediaisaguidedmedia?()AgeostationarysatelliteBlow-altitudesatelliteCfiberopticsDwirelessLAN4．Theunitsofdataexchangedbyalink-layerprotocolarecalled().AFramesBSegmentsCDatagramsDbitstreams5．Whichofthefollowingoptionbelongstothecircuit-switchednetworks?()AFDMBTDMCVCnetworksDbothAandB6．()makessurethatneithersideofaconnectionoverwhelmstheothersidebysendingtoomanypacketstoofast.AReliabledatatransferBFlowcontrolCCongestioncontrolDHandshakingprocedure7．()meansthattheswitchmustreceivetheentirepacketbeforeitcanbegintotransmitthefirstbitofthepacketontotheoutboundlink.AStore-and-forwardtransmissionBFDMCEnd-to-endconnectionDTDM8．Datagramnetworksandvirtual-circuitnetworksdifferinthat().Adatagramnetworksarecircuit-switchednetworks,andvirtual-circuitnetworksarepacket-switchednetworks.Bdatagramnetworksarepacket-switchednetworks,andvirtual-circuitnetworksarecircuit-switchednetworks.Cdatagramnetworksusedestinationaddressesandvirtual-circuitnetworksuseVC.numberstoforwardpacketstowardtheirdestination.DdatagramnetworksuseVC.numbersandvirtual-circuitnetworksusedestinationaddressestoforwardpacketstowardtheirdestination.9．Inthefollowingoptions,whichoneisnotaguidedmedia?()Atwisted-pairwireBfiberopticsCcoaxialcableDsatellite10．Processingdelaydoesnotincludethetimeto().Aexaminethepacket’sheaderBwaittotransmitthepacketontothelinkCdeterminewheretodirectthepacketDcheckbit-errorinthepacket11．Inthefollowingfourdescriptions,whichoneiscorrect?()AThetrafficintensitymustbegreaterthan1.BThefractionoflostpacketsincreasesasthetrafficintensitydecreases.CIfthetrafficintensityisclosetozero,theaveragequeuingdelaywillbeclosetozero.DIfthetrafficintensityisclosetoone,theaveragequeuingdelaywillbeclosetoone.12．TheInternet’snetworklayerisresponsibleformovingnetwork-layerpacketsknownas()fromonehosttoanother.AframeBdatagramCsegmentDmessage13．Theprotocolsofvariouslayersarecalled().AtheprotocolstackBTCP/IPCISPDnetworkprotocol14．Therearetwoclassesofpacket-switchednetworks:()networksandvirtual-circuitnetworks.AdatagramBcircuit-switchedCtelevisionDtelephone15．Accessnetworkscanbelooselyclassifiedintothreecategories:residentialaccess,companyaccessand()access.AcabledBwirelessCcampusDcityareaQuestion16～172Suppose,aistheaveragerateatwhichpacketsarriveatthequeue,Risthetransmissionrate,andallpacketsconsistofLbits,thenthetrafficintensityis(16),anditshouldnogreaterthan(17).16．ALR／aBLa／RCRa／LDLR／a17．A2B1C0D-118．IntheInternet,theequivalentconcepttoendsystemsis().AhostsBserversCclientsDrouters19．IntheInternet,endsystemsareconnectedtogetherby().AcopperwireBcoaxialcableCcommunicationlinksDfiberoptics20．EndsystemsaccesstotheInternetthroughits().AmodemsBprotocolsCISPDsockets21．Endsystems,packetswitches,andotherpiecesoftheInternet,run()thatcontrolthesendingandreceivingofinformationwithintheInternet.AprogramsBprocessesCapplicationsDprotocols22．Therearemanyprivatenetworks,suchasmanycorporateandgovernmentnetworks,whosehostscannotexchangemessageswithhostsoutsideoftheprivatenetwork.Theseprivatenetworksareoftenreferredtoas().AinternetsBLANCintranetsDWAN23．Theinternetallows()runningonitsendsystemstoexchangedatawitheachother.AclientsapplicationsBserverapplicationsCP2PapplicationsDdistributedapplications24．TheInternetprovidestwoservicestoitsdistributedapplications:aconnectionlessunreliableserviceand()service.AflowcontrolBconnection-orientedreliableCcongestioncontrolDTCP25．Itdefinestheformatandtheorderofmessagesexchangedbetweentwoormorecommunicatingentities,aswellastheactionstakenonthetransmissionand/orreceiptofamessageorotherevent.Thesentencedescribes().AInternetBprotocolCintranetDnetwork26．Inthefollowingoptions,whichdoesnotdefineinprotocol?()AtheformatofmessagesexchangedbetweentwoormorecommunicatingentitiesBtheorderofmessagesexchangedbetweentwoormorecommunicatingentitiesCtheactionstakenonthetransmissionofamessageorothereventDthetransmissionsignalsaredigitalsignalsoranalogsignals27．Inthefollowingoptions,whichisdefinedinprotocol?()Atheactionstakenonthetransmissionand/orreceiptofamessageorothereventBtheobjectsexchangedbetweencommunicatingentitiesCthecontentintheexchangedmessagesDthelocationofthehosts28．Inthefollowingoptions,whichdoesnotbelongtothenetworkedge?()AendsystemsBroutersCclientsDservers29．Inthefollowingoptions,whichbelongstothenetworkcore?()AendsystemsBroutersCclientsDservers30．Inthefollowingoptions,whichisnotthebundledwiththeInternet’sconnection-orientedservice?()AreliabledatatransferBguaranteeofthetransmissiontimeCflowcontrolDcongestion-control31．Anapplicationcanrelyontheconnectiontodeliverallofitsdatawithouterrorandintheproperorder.Thesentencedescribes().Aflowcontrol3Bcongestion-controlCreliabledatatransferDconnection-orientedservice32．Itmakessurethatneithers