川大软院计网选择题答案Chapter1(含答案)

1.1  Inthefollowingoptions,whichdoesnotdefineinprotocol?( D )A    theformatofmessagesexchangedbetweentwoormorecommunicatingentitiesB     theorderofmessagesexchangedbetweentwoormorecommunicatingentitiesC     theactionstakenonthetransmissionofamessageorothereventD    thetransmissionsignalsaredigitalsignalsoranalogsignals 1.2  Inthefollowingoptions,whichisdefinedinprotocol?( A )A    theactionstakenonthetransmissionand/orreceiptofamessageorothereventB    theobjectsexchangedbetweencommunicatingentitiesC    thecontentintheexchangedmessagesD    thelocationofthehosts 1.3  Anapplicationcanrelyontheconnectiontodeliverallofitsdatawithouterrorandintheproperorder.Thesentencedescribes(C  ).A   flowcontrol                    B   congestion-controlC   reliabledatatransfer                  D   connection-orientedservice 1.4  TheInternet’sconnection-orientedservicehasaname,itis( A ).A   TCP                            B   UDPC   TCP/IP                          D   IP 1.5  TheInternet’sconnectionlessserviceiscalled( B ).A   TCP                            B   UDPC   TCP/IP                          D    IP 1.6  Whichofthefollowingnodesbelongstothenetworkcore?CA.aWebServer                                            B.aHostwithWin2003ServerC.aRouterwithNATservice                      D.aSupernodeonSkypeNetwork  1.7  IntheInternet,theequivalentconcepttoendsystemsis(  )A.A    hosts                         B     serversC     clients                         D    routers 1.8  IntheInternet,endsystemsareconnectedtogetherby( C ).A    copperwire                       B     coaxialcableC     communicationlinks               D    fiberoptics 1.9  EndsystemsaccesstotheInternetthroughits(C  ).A    modems                          B     protocolsC     ISP                           D    sockets 1.10  Inthefollowingoptions,whichbelongstothenetworkcore?( B )A   endsystems                      B   routersC   clients                           D   servers 1.11  Endsystems,packetswitches,andotherpiecesoftheInternet,run( D )thatcontrolthesendingandreceivingofinformationwithintheInternet.A    programs                         B     processesC     applications                      D    protocols 1.12  Theinternetallows( D )runningonitsendsystemstoexchangedatawitheachother.A    clientsapplications                  B     serverapplicationsC     P2Papplications                  D    distributedapplications 1.13  Theprotocolsofvariouslayersarecalled( A ).A    theprotocolstack                  B     TCP/IPC     ISP                                  D    networkprotocol 1.14  IntheOSIreferencemodel,theupperlayersoftheOSImodelare,incorrectorderDA      Session,application,presentationB     Session,presentation,applicationC      Session,application,presentation,physicalD      Application,presentation,session 1.15  ThelowerlayersoftheOSImodelare,incorrectorderDA        physical,system,network,logicalB        physical,logical,network,systemC        physical,transport,network,datalinkD        physical,datalink,network,transport 1.16  TheInternetProtocol(IP)generallycorrespondstowhichOSIlayer?AA        Network(layerthree)B        Transport(layerfour)C       Datalink(layertwo)D        Session(layerfive) 1.17  WhatlayeroftheOSImodelisdesignedtoperformerrordetectionfunctions?BA        PhysicalB        DatalinkC        NetworkD        transport 1.18  WhichofthefollowingprotocollayersisnotexplicitlypartoftheInternetProtocolStack?_____B____A.applicationlayer                                              B.sessionlayerC.datalinklayer                                                  D.transportlayer 1.19  The5-PDUiscalled__A_A.message                                                           B.segment                C.datagram                                                         D.frame 1.20  TheInternet’snetworklayerisresponsibleformovingnetwork-layerpacketsknownasB(  )fromonehosttoanother.A    frame                                 B     datagramC     segment                               D    message 1.21  Transport-layerpacketsarecalled:BA.message                 B.segment                 C.datagram               D.frame 1.22  Theunitsofdataexchangedbyalink-layerprotocolarecalled(  A).A    Frames                               B     SegmentsC     Datagrams                     D    bitstreams 1.23  Therearetwofundamentalapproachestobuildinganetworkcore,( B )andpacketswitching.A   electricalcurrentswitching             B   circuitswitchingC   dataswitching                    D   messageswitching  1.24  Datagramnetworksandvirtual-circuitnetworksdifferinthat( C ).A    datagramnetworksarecircuit-switchednetworks,andvirtual-circuitnetworksarepacket-switchednetworks.B     datagramnetworksarepacket-switchednetworks,andvirtual-circuitnetworksarecircuit-switchednetworks.C     datagramnetworksusedestinationaddressesandvirtual-circuitnetworksuseVC.numberstoforwardpacketstowardtheirdestination.D    datagramnetworksuseVC.numbersandvirtual-circuitnetworksusedestinationaddressestoforwardpacketstowardtheirdestination. 1.25  (A  )meansthattheswitchmustreceivetheentirepacketbeforeitcanbegintotransmitthefirstbitofthepacketontotheoutboundlink.A    Store-and-forwardtransmission       B     FDMC     End-to-endconnection            D    TDM 1.26  In( C )networks,theresourcesneededalongapathtoprovideforcommunicationbetweentheendsystemarereservedforthedurationofthecommunicationsession.A   packet-switched                 B   data-switchedC   circuit-switched                   D   message-switched 1.27  In( A )networks,theresourcesarenotreserved;asession’smessagesusetheresourcesondemand,andasaconsequence,mayhavetowaitforaccesstocommunicationlink.A   packet-switched                  B   data-switchedC   circuit-switched                   D   message-switched  1.28  Inacircuit-switchednetwork,ifeachlinkhas n circuits,foreachlinkusedbytheend-to-endconnection,theconnectiongets(  A)ofthelink’sbandwidthforthedurationoftheconnection.A   afraction1/n                     B   allC   1/2                             D   ntimes 1.29  For(C  ),thetransmissionrateofacircuitisequaltotheframeratemultipliedbythenumberofbitsinaslot.A   CDMA                        B   packet-switchednetworkC   TDM                           D   FDM 1.30  Thenetworkthatforwardspacketsaccordingtohostdestinationaddressesiscalled(  D)network.A   circuit-switched                 B   packet-switchedC   virtual-circuit                     D   datagram 1.31  Thenetworkthatforwardspacketsaccordingtovirtual-circuitnumbersiscalled( C )network.A   circuit-switched                 B   packet-switchedC   virtual-circuit                     D   datagram 1.32  Thetimerequiredtopropagatefromthebeginningofthelinktothenextrouteris(  C).A   queuingdelay                         B   processingdelayC   propagationdelay                      D   transmissiondelay 1.33  Processingdelaydoesnotincludethetimeto(B  ).A    examinethepacket’sheaderB     waittotransmitthepacketontothelinkC     determinewheretodirectthepacketD    checkbit-errorinthepacket 1.34  Inthefollowingfourdescriptions,whichoneiscorrect?(  C)A    Thetrafficintensitymustbegreaterthan1.B     Thefractionoflostpacketsincreasesasthetrafficintensitydecreases.C     Ifthetrafficintensityisclosetozero,theaveragequeuingdelaywillbeclosetozero.D    Ifthetrafficintensityisclosetoone,theaveragequeuingdelaywillbeclosetoone. 1.35  Suppose, a istheaveragerateatwhichpacketsarriveatthequeue, R isthetransmissionrate,andallpacketsconsistof L bits,thenthetrafficintensityis( B ),A    LR／a                           B    La／RC    Ra／L                          D    LR／a  1.36  Supposethereisexactlyonepacketswitchbetweenasendinghostandareceivinghost.Thetransmissionratesbetweenthesendinghostandtheswitchandbetweentheswitchandthereceivinghostare R1 and R2,respectively.Assumingthattheswitchusesstore-and-forwardpacketswitching,whatisthetotalend-to-enddelaytosendapacketoflength L?(Ignorequeuingdelay,propagationdelay,andprocessingdelay.)( A )A   L/R1＋L/R2                            B   L/R1C   L/R2                              D   noneoftheabove 1.37  Wearesendinga30MbitMP3filefromasourcehosttoadestinationhost.Supposethereisonlyonelinkbetweensourceanddestinationandthelinkhasatransmissionrateof10Mbps.Assumethatthepropagationspeedis2*108 meters/sec,andthedistancebetweensourceanddestinationis10,000km.Alsosupposethatmessageswitchingisused,withthemessageconsistingoftheentireMP3file.Howmanybitswillthesourcehavetransmittedwhenthefirstbitarrivesatthedestination?CA.1bit   B.30,000,000bits  C.500,000bits   D.noneoftheabove 1.38  Inthefollowingentries,whichisnotakindofaccessnetwork?(D  )A   residentialaccess                  B   companyaccessC   wirelessaccess                  D   localaccess  1.39  Thefollowingtechnologiesmaybeusedforresidentialaccess,exceptDA.HFC                      B.DSL                       C.Dial-upmodem           D.FDDI 1.40  Whichkindofmediaisnotaguidedmedia?(  D)A    twisted-paircopperwire             B     acoaxialcableC     fiberoptics                     D    digitalsatellitechannel  授课：XXX授课：XXX授课：XXX