川大软院计网选择题答案Chapter3(含答案)

川大软院计网选择题答案Chapter3(含答案)川大软院计网选择题答案Chapter3(含答案)川大软院计网选择题答案Chapter3(含答案)V:1.0精细整理，仅供参考川大软院计网选择题答案Chapter3(含答案)日期：20xx年X月CHAPTER3:TRANSPORTLAYER

transport-layerprotocolprovidesforlogicalcommunicationbetween___C_.processessystemsprotocolsrunin__D__.systemstransportlayer,thesendsidebreaksapplicationmessagesinto___B_,passestonetworklayer.streamsreceivesideoftransportlayerreassemblessegmentsintomessages,passesto__A__videdbytransportlayerinclude__C__.andFTPandIPandUDPofthefollowingservicesisnotprovidedbyTCPDdatatransfersdatatransfersandflowcontrolscontrolsguaranteesandbandwidthguaranteestwominimaltransport-layerservices----___A_and____----aretheonlytwoservicesthatUDPprovidesdatadelivery,errorcheckingcontrol,reliabledatatransfercontrol,congestioncontroldatatransfer,errorcheckingofferswhichofthefollowingbenefitsrelativetoTCPCguaranteesthatIndividualpacketsofatransmissionwillarrive“inorder”supportsaself-regulating“throttle”featurethatpreventsnetworksaturationconsumesfewercomputerresourcesbynotmaintainingconnectionstateoftheaboveofthefollowingapplicationsnormallyusesUDPservicesBmultimediajobofgatheringdatachunks,encapsulatingeachdatachunkwithheaderinformationtocreatesegmentsandpassingthesegmentstothenetworkiscalled__A__.

jobofdeliveringthedatainatransport-layersegmenttothecorrectsocketiscalled_B___.

number’sscopeis___B_to____.,1023,65535,127,255portnumbersrangingfrom__C__to____arecalledwell-knownportnumberandarerestricted.,127,65535,1023,255UDPheaderhasonlyfourfields,theyare__A__.portnumber,destinationportnumber,lengthandchecksumportnumber,destinationportnumber,sourceIPanddestinationIPIP,destinationIP,sourceMACaddressanddestinationMACaddressIP,destinationIP,sequencenumberandACKsequencenumberfieldofLengthinUDPsegmentspecifiesthelengthof___B_.UDPsegment,notincludingtheheaderUDPsegment,includingtheheaderUDPsegment’sheaderLengthfieldofthefollowingaboutTCPconnectionisnotcorrectAisabroadcastconnectionisapoint-to-pointconnectionisapipelinedconnectionisafullduplexconnectionthefollowingfourdescriptionsaboutMSSandMTU,whichoneisnotcorrectCMSSistypicallysetbyMTUMSSisthemaximumsizeoftheTCPsegmentincludingheadersMSSisthemaximumamountofapplication-layerdatainthesegmentMTUmeansthelargestlink-layerframeisthebytestreamnumberoffirstbyteinthesegment.numbernumbernumberisthebytesequencenumbersofnextbyteexpectedfromotherside.numbernumbernumberthefollowingfouroptions,whichoneiscorrectDthatthelastSampleRTTinaTCPconnectionisequalto1sec.ThenthecurrentvalueofTimeoutIntervalwillnecessarilybe≤1sectimeoutshouldbelessthantheconnection’sRTTthatthelastSampleRTTinaTCPconnectionisequalto1sec.ThenthecurrentvalueofTimeoutIntervalwillnecessarilybe≥1secvariationsintheSampleRTTaresmoothedoutinthecomputationoftheEstimatedRTTaretwo16-bitintegers:1110011001100110,1101010101010101.Theirchecksumis__A__.hostAsendshostBoneTCPsegmentwithsequencenumber418,acknowledgementnumber571,and4bytesofdata.Thenthesequencenumberintheacknowledgementtothissegmentis_____C____

B.418

C.571

D.575TCPonlyacknowledgesbytesuptothefirstmissingbyteinthestream,TCPissaidtoprovide__D__.ACKsacknowledgementsduplicateACKsacknowledgementswedefineNtobethewindowsize,basetobethesequencenumberoftheoldestunacknowledgedpacket,andnext-seq-numtobethesmallestunusedsequencenumber,thentheinterval[nextseqnum,base+N-1]correspondstopacketthat__A__.besentimmediately

alreadybeentransmittedandacknowledgedbeusedbeensentbutnotyetacknowledgedofthefollowingisnotapipeliningrepeatisthemaindifferencebetweenstop-and-waitandpipelinedreliabledatatransferprotocolBpipelinedprotocolusestheNAKpackets,whereasinthestop-and-waitprotocolsendersalwayswaitforACKpackets.thepipelinedprotocol,thesendercansendseveralpacketsinrow,whereasinthestop-and-waitprotocolthesendercannotsendthepacketsinrow.thepipelinedprotocol,thereceivermustsendoneACKforseveralpackets(cumulativeACK),whereasinthestop-and-waitprotocolthereceivercannotsendthecumulativeACK.pipelinedprotocolusestimeouts,whereasthestop-and-waitprotocoldoesnotusethetimeout.retransmitmeansinthecasethat__D__duplicateACK-sarereceived,theTCPsenderresendsegmentbeforetimerexpires.isaspeeding-matchingservice---matchingtheratewhichthesenderissendingagainsttherateatwhichthereceivingapplicationisreading.control

controlcontrol

controlprovidesflowcontrolbyhavingthesendermaintainavariablecalledthe__D__.windowwindowwindowRcvBuffer=20,LastByteRcvd=20,LastByteRead=15,thenRcvWindow=__B__.thefollowingfourdescriptionsaboutTCPconnectionmanagement,whichoneisnotcorrectDofthetwoprocessesparticipatinginaTCPconnectioncanendtheconnectiontheFINbitissetto1,itmeansthatitwantstoclosetheconnectionthefirsttwostepofthethree-wayhandshake,theclientandserverrandomlychooseaninitialsequencenumberthethreesegmentsofthethree-wayhandshake,theSYNbitmustbesetto1doesTCPsenderperceivecongestionDatimeouteventareceivingduplicateACK-seventAandBAorBaretwostatesinTCPcongestioncontrol,whichare_C___.startand