计算机网络英文题库(附答案)chapter3

Chapter3TransportLayer1.Atransport-layerprotocolprovidesforlogicalcommunicationbetween____.AApplicationprocessesBHostsCRoutersDEndsystems2.Transport-layerprotocolsrunin____.AServersBClientsCRoutersDEndsystems3.Intransportlayer,thesendsidebreaksapplicationmessagesinto____,passestonetworklayer.AFramesBSegmentsCData-gramsDbitstreams4.Servicesprovidedbytransportlayerinclude____.AHTTPandFTPBTCPandIPCTCPandUDPDSMTP5.WhichofthefollowingservicesisnotprovidedbyTCP?ADelayguaranteesandbandwidthguaranteesBReliabledatatransfersandflowcontrolsCCongestioncontrolsDIn-orderdatatransfers6.Thesetwominimaltransport-layerservices----____and____----aretheonlytwoservicesthatUDPprovides!Aprocess-to-processdatadelivery,errorcheckingBcongestioncontrol,reliabledatatransferCflowcontrol,congestioncontrolDIn-orderdatatransfer,errorchecking7.Portnumber’sscopeis____to____.A0,1023B0,65535C0,127D0,2558.Theportnumbersrangingfrom____to____arecalledwell-knownportnumberandarerestricted.A0,1023B0,65535C0,127D0,2559.UDPsocketidentifiedbytwocomponents,theyare____.AsourceIPaddressesandsourceportnumbersBsourceIPaddressesanddestinationIPaddressesCdestinationIPaddressanddestinationportnumbersDdestinationportnumbersandsourceportnumbers10.TCPsocketidentifiedbya(an)____.A1-tupleB2-tupleC3-tupleD4-tuple11.WhichofthefollowingapplicationsnormallyusesUDPservices?ASMTPBStreamingmultimediaCFTPDHTTP12.Reliabledatatransferprotocoloveraperfectlyreliablechannelis____.Ardt1.0Brdt2.0Crdt3.0Drdt2.113.Reliabledatatransferprotocoloverachannelwithbiterrorsandpacketlossesis____.Ardt1.0Brdt2.0Crdt3.0Drdt2.114.Whichofthefollowingaboutreliabledatatransferoverachannelwithbiterrorsisnotcorrect?ARDT2.0:assumingACKandNAKwillnotbecorruptedBRDT2.1:assumingACKandNAKcanbecorruptedCRDT2.2:onlyuseACK-sDRDT2.2:usebothACK-sandNAK-s15.Whichofthefollowingprotocolsisnotpipeliningprotocols?ATCPBrdt3.0CGO-BACK-NDselectiverepeat16.WhichofthefollowingisnotcorrectaboutGBNprotocol?AOnlyusingACK-sBUsingcumulativeACK-sCReceiverdiscardsallout-of-orderpacketsDItisnotpipelinedprotocol17.WhichofthefollowingisnotcorrectaboutSRprotocol?AreceiverindividuallyacknowledgesallcorrectlyreceivedpacketsBsenderonlyresendspacketsforwhichACKnotreceivedCItlimitssequencenumberofsentbutun-ACK-edpacketsDItisnotapipelinedprotocol18.WhichofthefollowingaboutTCPconnectionisnotcorrect?AItisabroadcastconnectionBItisapoint-to-pointconnectionCItisapipelinedconnectionDItisafullduplexconnection19.TheSYNsegmentisusedfor____.ATCPconnectionsetupBTCPflowcontrolCTCPcongestioncontrolDClosingaTCPconnection20.TheFINsegmentisusedfor____.ATCPconnectionsetupBTCPflowcontrolCTCPcongestioncontrolDClosingaTCPconnection21.HowdoesTCPsenderperceivecongestion?AThroughatimeouteventBThroughareceivingduplicateACK-seventCBothAandBDEitherAorB22.Extendinghost-to-hostdeliverytoprocess-to-processdeliveryiscalledtransport-layer____and.Amultiplexingandde-multiplexingBstoringandforwardingCforwardingandfilteringDswitchingandrouting23.UDPisa____servicewhileTCPisaconnection-orientedservice.AConnectionlessBReliableCConnection-orientedDIn-order24.TheUDPheaderhasonlyfourfields,theyare____.ASourceportnumber,destinationportnumber,lengthandchecksumBSourceportnumber,destinationportnumber,sourceIPanddestinationIPCsourceIP,destinationIP,sourceMACaddressanddestinationMACaddressDsourceIP,destinationIP,sequencenumberandACKsequencenumber25.Therearetwo16-bitintegers:1110011001100110,1101010101010101.Theirchecksumis____.A0100010001000011B1011101110111100C1111111111111111D100000000000000026.Themaximumamountofdatathatcanbegrabbedandplacedinasegmentislimitedbythe____.AMaximumsegmentsize(MSS)BMTUCChecksumDSequencenumber27.TheMSSistypicallysetbyfirstdeterminingthelengthofthelargestlink-layerframethatcanbesentbythelocalsendinghost----theso-called____.AMaximumtransmissionunit(MTU)BMSSCChecksumDSequencenumber28.AFilesizeof500,000bytes,MSSequals1000bytes.WhenwewanttotransmitthisfilewithTCP,thesequencenumberofthefirstsegmentis0,andthesequencenumberofthesecondsegmentis____.A1000B999C1001D50000029.BecauseTCPonlyacknowledgesbytesuptothefirstmissingbyteinthestream,TCPissaidtoprovide____.ACumulativeacknowledgementsBSelectiveacknowledgementsC3duplicateACKsDpositiveACKs30.Providedα=0.125,currentvalueofEstimated-RTTis0.4s,Sample-RTTis0.8s,thenthenewvalueofEstimated-RTTis____s.A0.45B0.6C0.7D0.831.ProvidedRcvBuffer=20,LastByteRcvd=20,LastByteRead=15,thenRcvWindow=____.A14B15C16D1032.TCPservicedoesnotprovide____.AReliabledatatransferBFlowcontrolCDelayguaranteeDCongestioncontrol33.TherearetwostatesinTCPcongestioncontrol,whichare____.AslowstartandcongestionavoidanceBsafestartandcongestionavoidanceCslowstartandcongestionabandonDsafestartandcongestionabandon34.Thetransport-layerprotocolprovideslogicalcommunicationbetween____,andthenetwork-layerprotocolprovideslogicalcommunication____.Ahosts,processesBprocesses,hostsCthreads,processesDprocesses,threads35.ToimplementthemulticastservicestheInternetemploysthe____protocol.AFTPBTCPCIGMPDUDP36.Ifanapplicationdeveloperchooses____protocol,thentheapplication