川大软院计网选择题答案Chapter4(含答案)

CHAPTER4:NETWORKLAYER1.Whichofthefollowinggroupsbelongstonetworklayerprotocol?_____D____A.IP,TCPandUDPB.ARP,IP,andUDPC.FTP,IMAPandIPD.ICMP,BGP,andRIP2.The3-PDUisnamedas____C_____A.messageB.packetC.datagramD.segment3.Inadatagramnetwork,theforwardingdecisionisbasedonthevalueofthe____Bfieldinthepacketheader.A.sourceaddressB.destinationaddressC.labelD.Noneofthechoicesare4.HOLblockinghappenson____A_____A.inputportB.outputportC.switchingfabricsD.allofabove5.Ifnofreebuffersinrouter,thearrivingpacketswillbe:AA.droppedB.queuedC.returnedD.marked6.DuringnormalIPpacketforwardingatarouter,whichofthefollowingpacketfieldsareupdated?____C____A.SourceIPaddressB.DestinationIPaddressC.ChecksumD.Destinationportnumber7.WhichofthefollowingIPaddressdoesn’tbelongtothe202.115.32.0/25network?______D___A.202.115.32.1B.202.115.32.11C.202.115.32.120D.202.115.32.1298.YouaregivenanIPnetworkof192.168.5.0andtoldthatyouneedtoseparatethisnetworkintosubnetworksthatcansupportamaximumof30hostspersubnet.Thiswillhelpalleviatecongestiononthenetwork.Whatsubnetmaskcanyouusetocreatethesubnetsnecessarytomeetthegivencriteria?___C______A.255.255.255.0B.255.255.255.128C.255.255.255.224D.255.255.255.2409.AnIPdatagramof1500bytes(20byteofIPheaderplus1480bytesofIPpayload)arrivesatarouterandmustbeforwardedtoalinkwithanMTUof500bytes.Thustherouterhastofragmentthedatagram.Tothelastfragment,thevalueofoffsetshouldbe_____D____A.1440B.1000C.186D.18010.IPisa____C_____protocol.A.connection-orientedunreliableB.connection-orientedreliableC.connectionlessunreliableD.connectionlessreliable11.WhichICMPmessagetypeisthebasisfortheTracerouteutility?BA.EchoRequestB.TTLexpiredC.HostUnreachableD.FragmentReassemblyTimeExceed12.Routersinthepatharenotallowedto_________________B__________.A.fragmentthepackettheyreceiveB.changesourceordestinationaddressC.decapsulatethepacketD.Allofthechoicesarecorrect13.____B_____allowsasitetouseasetofprivateaddressesforinternalcommunicationandasetofglobalInternetaddressesforcommunicationwiththerestoftheworld.A.DHCPB.NATC.ICMPD.Noneofthechoicesarecorrect14.HowmanybitsarethereinIPv6?______C___A.32B.64C.128D.25615.InCIDRnotation,whichofthefollowingnetworkscontainshost192.168.14.2?CA.192.168.10.0/22B.192.168.11.0/21C.192.168.12.0/23D.192.168.13.0/2416.WhatisthelimitedbroadcastaddresscorrespondingtothenodewiththefollowingIPaddress:131.15.46.59?DA.131.15.46.255B.131.15.255.255C.255.255.255.255D.Noneoftheabove17.InclassfulIPaddressing,howmanynetworkbitsdoes125.140.128.16have?AA.8B.16C.24D.3218.WhatisthebroadcastIPaddressfor193.140.141.128/26?DA.193.140.141.128B.193.140.141.127C.255.255.255.63D.193.140.141.19119.What’sanetwork?FromIPaddressperspectivetheycanphysicallyreacheachotherwithoutinterveningrouterandthedeviceinterfaceswith:CA.sameIPaddressB.sameTCPport#C.samenetworkpartofIPaddressD.samehostpartofIPaddress20.TheInternet’snetworklayerhasthreemajorcomponents,thefirstcomponentistheIPprotocol,thesecondcomponentistheroutingprotocol,thefinalcomponentis____.DA.forwardingB.addresstranslationC.checkD.ICMP21.IPaddressingassignsanaddressto223.10.198.250/29,thenetworkaddressforthisnetworkis____.A（）A.223.10.198.248B.223.10.198.250C.223.10.198.0D.223.10.0.022.Therearetwo16-bitintegers:1110011001100110,1101010101010101.TheirchecksumisA____.A.0100010001000011B.1011101110111100C.1111111111111111D.100000000000000023.Theuseofhierarchyinroutingtablescan__A______thesizeoftheroutingtables.A.reduceB.increaseC.neitherreducenorincreaseD.Noneofthechoicesarecorrect24.Whichofthefollowingprotocoldoesn’tbelongtointra-ASroutingprotocol?_____B____A.RIPB.BGPC.OSPFD.IRAP25.Whichofthefollowingprotocolbelongstointra-ASroutingprotocol?______A___A.RIPB.BGPC.DV(DistanceVector)D.LS(LinkState)26.InOSPFnetwork,a____B_____belongstobothanareaandthebackbone.A.internalrouterB.areaborderrouterC.boundaryrouterD.backbonerouter27._A___isaninter-domainroutingprotocolusingpathvectorrouting.A.BGPB.RIPC.OSPFD.Noneofthechoicesarecorrect28.RIPusestheservicesof___C____.A.TCPB.IPC.UDPD.Noneofthechoicesarecorrect29.TheRoutingInformationProtocol(RIP)isanintra-domainroutingbasedon_______A__routing.A.distancevectorB.linkstateC.pathvectorD.alloftheabove30.Whichofthefollowingalgorithmhasthesocalledcount-to-infinityproblem?CA.FloodingalgorithmB.Link-statealgorithmC.DistancevectoralgorithmD.Noneoftheabove