计算机网络教程自顶向下方法选择题及答案

./Chapter4NetworkLayer1.PacketizingatthenetworklayerinvolvesA)EncapsulatingthepayloadatthesourceB)AddsaheaderthatcontainsthesourceanddestinationinformationC)DecapsulatingthepayloadatthedestinationD)Allofthechoicesarecorrect2.Routersinthepatharenotallowedto___________________________.A)fragmentthepackettheyreceiveB)decapsulatethepacketC)changesourceordestinationaddressD)Allofthechoicesarecorrect3.ThenetworklayerintheInternetprovides_________________.A)comprehensiveerrorandflowcontrol.B)limitederrorcontrol,butnoflowcontrol.C)comprehensiveerrorcontrolbutlimitedflowcontrol.D)Allofthechoicesarecorrect4.Inavirtual-circuitapproach,theforwardingdecisionisbasedonthevalueofthe_____________fieldinthepacketheader.A)sourceaddressB)destinationaddressC)labelD)Noneofthechoicesarecorrect5.Inadatagramapproach,theforwardingdecisionisbasedonthevalueofthe_____________fieldinthepacketheader.A)sourceaddressB)destinationaddressC)labelD)Noneofthechoicesarecorrect6.Theperformanceofanetworkcanbemeasuredintermsof________.A)delayB)throughputC)packetlossD)allofthechoicesarecorrect7.Transmissiondelay(time)istheratioof______________________.A)transmissionratetopacketlengthB)transmissionratetodistanceC)packetlengthtotransmissionrateD)processingtimetotransmissionrate8.Propagationdelay(time)istheratioof______________________.A)transmissionratetopropagationspeedB)propagationspeedtodistanceC)packetlengthtopropagationspeedD)distancetopropagationspeed9.Whentheloadinthenetworkreachesthenetworkcapacity,thepacketdelay___________andthenetworkthroughputreaches______________.A)increasessharply;itsminimumB)increasessharply;itsmaximumC)decreasessharply;itsminimumD)decreasessharply;itsmaximum10.Inopen-loopcongestioncontrol,policiesareapplied____________________.A)topreventcongestionbeforeithappensB)toalleviatecongestionafterithappensC)toeitherpreventcongestionbeforeithappensortoalleviatecongestionafterithappensD)Noneofthechoicesarecorrect11.The__________________techniqueisoneoftheopen-loopcongestionpolicyA)backpressureB)chokepacketC)implicitsignalingD)Noneofthechoicesarecorrect12.The__________________techniqueisoneoftheclose-loopcongestionpolicyA)acknowledgmentpolicyB)chokepacketC)discardingpolicyD)Noneofthechoicesarecorrect13.IPisa_________protocol.A)connection-orientedunreliableB)connection-orientedreliableC)connectionlessunreliableD)connectionlessreliable14.AnHLENvalueofdecimal10means_______.A)thereare10bytesofoptionsB)thereare10bytesintheheaderC)thereare40bytesofoptionsD)thereare40bytesintheheader15.Ifthefragmentoffsethasavalueof100,itmeansthat_______.A)thedatagramhasnotbeenfragmentedB)thedatagramis100bytesinsizeC)thefirstbyteofthedatagramisbyte800D)Noneofthechoicesarecorrect16.Whatisneededtodeterminethenumberofthelastbyteofafragment?A)offsetnumberB)totallengthC)bothoffsetnumberandthetotallengthD)Noneofthechoicesarecorrect17.TheIPheadersizeis_______byteslong.A)20to60B)20C)60D)Noneofthechoicesarecorrect18.PacketsintheIPlayerarecalled_________.A)segmentsB)datagramsC)framesD)Noneofthechoicesarecorrect19.Thetotallengthfielddefinesthetotallengthofthedatagram_________.A)includingtheheaderB)excludingtheheaderC)excludingtheoptionlengthD)Noneofthechoicesarecorrect20.Whenadatagramisencapsulatedinaframe,thetotalsizeofthedatagrammustbelessthanthe_______.A)MUTB)MATC)MTUD)Noneofthechoicesarecorrect21.AnIPv4addressisnormallyrepresentedinbase____indotted-decimalnotation.A)16B)256C)10D)Noneofthechoicesarecorrect22.Inclassfuladdressing,theIPv4addressspaceisdividedinto_______classes.A)3B)4C)5D)Noneofthechoicesarecorrect23.Thenumberofaddressesassignedtoanorganizationinclasslessaddressing_______.A)canbeanynumberB)mustbeamultipleof256C)mustbeapowerof2D)Noneofthechoicesarecorrect24.Thefirstaddressassignedtoanorganizationinclasslessaddressing_______.A)mustbeevenlydivisiblebythenumberofaddressesintheorganizationB)mustbedivisibleby128C)mustbelongtooneoftheA,B,orCclassesD)Noneofthechoicesarecorrect25.Insubnetting,thenumberofaddressesineachsubnetmust_______.A)beapowerof2B)beamultipleof128C)bedivisibleby128D)Noneofthechoicesarecorrect26.WhatisthedefaultprefixlengthforclassAinCIDRnotation?A)9B)8C)16D)Noneofthechoicesarecorrect27.WhatisthedefaultprefixlengthforclassBinCIDRnotation?A)9B)8C)16D)Noneofthechoicesarecorrect28.WhatisthedefaultprefixlengthforclassCinCIDRnotation?A)24B)8C)16D)Noneofthechoicesarecorrect29.DHCPisa(an)___________layerprotocol.A)applicationB)transportC)networkD)data-link30.InDHCP,theclientuses________portandtheserveruses_________port.A)anephemeral;awell-knownB)awell-known;awell-knownC)awell-known;anephemeralD)Noneofthechoicesarecorrect31.DHCPusestheservicesof_______.A)UDPB)TCPC)IPD)Noneofthechoicesarecorrect32._________allowsasitetouseasetofprivateaddressesforinternalcommunicationandasetofglobalInternetaddressesforcommunicationwiththerestoftheworld.A)DHCPB)NATC)IMCPD)Noneofthechoicesarecorrect33.Theideaofaddressaggregationwasdesignedtoalleviatetheincreaseinroutingtableentrieswhenusing________addressing.A)classfulB)classlessC)classfulorclasslessD)Noneofthechoicesarecorrect34.Theuseofhierarchyinroutingtablescan________thesizeoftheroutingtables.A)reduceB)increaseC)neitherreducenorincreaseD)Noneofthechoicesarecorrect35.ICMPisa(an)_________layerprotocol.A)application-layerprotocolthathelpsTCP/IPatthenetworklayerB)transport-layerprotocolthathelpsTCP/IPatthenetworklayerC)network-layerprotocol.D)data-linklayerprotocolthathelpsTCP/IPatthenetworklayer36.WhichofthefollowingistrueaboutICMPmessages?A)AnICMPerrormessagemaybegeneratedforanICMPerrormessage.B)AnICMPerrormessagemaybegeneratedforafragmenteddatagram.C)AnICMPerrormessagemaybegeneratedforamulticastdatagram.D)Noneofthechoicesarecorrect37.Routinginsideanautonomoussystemisreferredtoas________routing.A)interdomainB)intradomainC)out-of-domainD)Noneofthechoicesarecorrect38.Routingbetweenautonomoussystemsisreferredtoas______routing.A)interdomainroutingB)intradomainroutingC)out-of-domainD)Noneofthechoicesarecorrect39.In_______routing,theleastcostroutebetweenanytwonodesistheroutewiththeminimumdistance.A)pathvectorB)distancevectorC)linkstateD)Noneofthechoicesarecorrect40.In________,eachnodemaintainsavector(table)ofminimumdistancestoeverynode.A)pathvectorB)distancevectorC)linkstateD)Noneofthechoicesarecorrect41.Indistancevectorrouting,eachnodeperiodicallysharesitsroutingtablewith_________andwheneverthereisachange.A)everyothernodeB)itsimmediateneighborsC)oneneighborD)Noneofthechoicesarecorrect42.TheRoutingInformationProtocol(RIP)isanintradomainroutingbasedon_________routing.A)distancevectorB)linkstateC)pathvectorD)Noneofthechoicesarecorrect43.Themetricusedby_______isthehopcount.A)OSPFB)RIPC)BGPD)Noneofthechoicesarecorrect44.InRIP,the________timercontrolstheadvertisingofregularupdatemessages.A)garbagecollectionB)expirationC)periodicD)Noneofthechoicesarecorrect45.InRIP,the________timerisusedtopurgeinvalidroutesfromthetable.A)garbagecollectionB)expirationC)periodicD)Noneofthechoicesarecorrect46.InRIP,the________timercontrolsthevalidityoftheroute.A)garbagecollectionB)expirationC)periodicD)Noneofthechoicesarecorrect47.RIPusestheservicesof_______.A)TCPB)UDPC)IPD)Noneofthechoicesarecorrect48.The_________routingusestheDijkstraalgorithmtobuildaroutingtable.A)distancevectorB)linkstateC)pathvectorD)Noneofthechoicesarecorrect49.TheOpenShortestPathFirst(OSPF)protocolisanintradomainroutingprotocolbasedon_______routing.A)distancevectorB)linkstateC)pathvectorD)Noneofthechoicesarecorrect50.The_______protocolallowstheadministratortoassignacost,calledthemetric,toeachroute.A)OSPFB)RIPC)BGPD)Noneofthechoicesarecorrect51.InOSPF,a________linkconnectstworouterswithoutanyotherhostorrouterinbetween.A)point-to-pointB)transientC)stubD)Noneofthechoicesarecorrect52.InOSPF,a_______linkisanetworkwithseveralroutersattachedtoit.A)point-to-pointB)transientC)stubD)Noneofthechoicesarecorrect53.InOSPF,a________linkisanetworkconnectedtoonlyonerouter.A)point-to-pointB)transientC)stubD)Noneofthechoicesarecorrect54.InOSPF,a________definesthelinksofanetwork.A)networklinkB)routerlinkC)summarylinktonetworkD)Noneofthechoicesarecorrect55.___________isaninterdomainroutingprotocolusingpathvectorrouting.A)BGPB)RIPC)OSPFD)Noneofthechoicesarecorrect56.Aone-to-allcommunicationbetweenonesourceandallhostsonanetworkisclassifiedasa_______communication.A)unicastB)multicastC)broadcastD)Noneofthechoicesarecorrect57.Aone-to-manycommunicationbetweenonesourceandaspecificgroupofhostsisclassifiedasa_______communication.A)unicastB)multicastC)broadcastD)Noneofthechoicesarecorrect58.Aone-to-onecommunicationbetweenonesourceandonedestinationisclassifiedasa_______communication.A)unicastB)multicastC)broadcastD)Noneofthechoicesarecorrect59.In______,therouterforwardsthereceivedpacketthroughonlyoneofitsinterfaces.A)unicastingB)multicastingC)broadcastingD)Noneofthechoicesarecorrect60.Inmulticastrouting,eachinvolvedrouterneedstoconstructa________pathtreeforeachgroup.A)averageB)longestC)shortestD)Noneofthechoicesarecorrect61.Inthe_______treeapproachtomulticasting,eachrouterneedstocreateaseparatetreeforeachsource-group.A)group-sharedB)source-basedC)destination-basedD)Noneofthechoicesarecorrect62.TheMulticastOpenShortestPathFirst(MOSPF)routingusesthe_______treeapproach.A)source-basedB)group-sharedC)destination-basedD)Noneofthechoicesarecorrect63.TheMulticastOpenShortestPathFirst(MOSPF)protocolisanextensionoftheOSPFprotocolthatusesmulticastroutingtocreatesource-basedtrees.Theprotocolisbasedon_______routing.A)distancevectorB)linkstateC)pathvectorD)Noneofthechoicesarecorrect64.InRPF,arouterforwardsonlythecopythathastraveledthe_______pathfromthesourcetotherouter.A)shortestB)longestC)averageD)Noneofthechoicesarecorrect65.RPFeliminatesthe________inthefloodingprocess.A)forwardingB)backwardingC)floodingD)Noneofthechoicesarecorrect66.RPBcreatesashortestpath_______treefromthesourcetoeachdestination.A)unicastB)multicastC)broadcastD)Noneofthechoicesarecorrect67.RPBguaranteesthateachdestinationreceives_________ofthepacket.A)onlyonecopyB)nocopiesC)multiplecopiesD)Noneofthechoicesarecorrect68.In________,themulticastpacketmustreachonlythosenetworksthathaveactivemembersforthatparticulargroup.A)RPFB)RPBC)RPMD)Noneofthechoicesarecorrect69._______addspruningandgraftingto_______tocreateamulticastshortestpathtreethatsupportsdynamicmembershipchanges.A)RPM;RPBB)RPB;RPMC)RPF;RPMD)Noneofthechoicesarecorrect70.__________isanimplementationofmulticastdistancevectorrouting.Itisasource-basedroutingprotocol,basedonRIP.A)MOSPFB)DVMRPC)CBTD)Noneofthechoicesarecorrect71.DVMRPisa________routingprotocol,basedonRIP.A)source-basedB)group-sharedC)destination-basedD)Noneofthechoicesarecorrect72.Pruningandgraftingarestrategiesusedin_______.A)RPFB)RPBC)RPMD)Noneofthechoicesarecorrect73.PIM-DMisusedwhenthenumberofrouterswithattachedmembersis______relativetothenumberofroutersintheinternet.A)largeB)smallC)moderateD)Noneofthechoicesarecorrect74.PIM-SMisusedwhenthenumberofrouterswithattachedmembersis______relativetothenumberofroutersintheinternet.A)largeB)smallC)moderateD)Noneofthechoicesarecorrect75.AnIPv6addressis_________bitslong.A)32B)64C)128D)25676.AnIPv6addressconsistsof________bytes(octets);A)4B)8C)16D)Noneofthechoicesarecorrect77.Inhexadecimalcolonnotation,a128-bitaddressisdividedinto_______sections,each_____hexadecimaldigitsinlength.A)8;2B)8;3C)8;4D)Noneofthechoicesarecorrect78.AnIPv6addresscanhaveupto__________hexadecimaldigits.A)16B)32C)8D)Noneofthechoicesarecorrect79.InIPv6,the_______fieldinthebaseheaderrestrictsthelifetimeofadatagram.A)versionB)priorityC)hoplimitD)Noneofthechoicesarecorrect80.The_________inIPv6isdesignedtoprovidespecialhandlingforaparticularflowofdata.A)flowlabelB)nextheaderC)hoplimitD)Noneofthechoicesarecorrect81.WhentwocomputersusingIPv6wanttocommunicatebutthepacketmustpassthroughanIPv4region,whichtransitionstrategyshouldbeused?A)tunnelingB)headertranslationC)eithertunnelingorheadertranslationD)Noneofthechoicesarecorrect82.WhenthemajorityoftheInternethasmovedtotheIPv6butsomestilluseIPv4,whichtransitionstrategyshouldbeused?A)tunnelingB)headertranslationC)eithertunnelingorheadertranslationD)Noneofthechoicesarecorrect83.Theprotocols__________________________inversion4arecombinedintoonesingleprotocol,ICMPv6.A)ARPandIGMPB)ICMPandIGMPC)ICMP,ARP,andIGMPD)NoneofthechoicesarecorrectDCBCBDCCBADBCDCCABACBCCAABCAABABBACDBABBBABCABBBBAABCAACBAACBABADCACABACABCCCBCAABC/v.