计算机网络与通信期末考试b_答案

1、四川大学期考试试题B闭卷20212021学年第2学期课程号：课序号：0?7课程名称：计算机网络与通信任课教师：等成绩：适用专业年级：06学生人数：印题份数：学号：姓名：测试须知四川大学学生参加由学校组织或由学校承办的各级各类测试,必须严格执行?四川大学测试工作治理方法?和?四川大学考场规那么?.有测试违纪作弊行为的,一律根据?四川大学学生测试违纪作弊处分条例?进行处理.四川大学各级各类测试的监考人员,必须严格执行?四川大学测试工作治理方法?、?四川大学考场规那么?和?四川大学监考人员责任?.有违反学校有关规定的,严格根据?四川大学教学事故认定及处理方法?进行处理.第一题第二题第三题第四题第五题

2、总分一、英译汉10分1.ISPINTERT效劳供给商2.NIC网络接口卡3.DNS域名效劳系统4.MAC介质接入限制5BGP边界网关协议6.MSSS大数据段尺寸7.FTP文件传输协议8MPLS多协议标签交换9AS自治系统10.packetsw让chin处组交换:、单项选择题每题1.5分,共30分1. Werefertothelink-layerpacketsaDA.messagesB.segmentsC.datagramsD.frames2. TheIPprotocolliesinCA.applicationlayerB.transportlayerC.networklayerD.linkla

3、yer3. AisaCircuit-switchednetwork.A.TDMB.DatagramnetworkC.InternetD.virtualcircuitnetwork4. ThepacketexperiencesaBdelayasitwaitstobetransmittedontothelink.A.processingdelayB.queuingdelayC.propagationdelayD.transmissiondelay5. DWhichthefollowingprotocolsdoesnotuseTCP/IPasitsunderlyingprotocols?A.SMTP

4、;B.FTP;C.TELNET;D.TFTP6. Whatisusedtospecifyplacementoftext,filesandobjectsthataretobetransferredfromthewebservertotheclient?BA.HTTPB.HTMLC.HDLCD.Alloftheabove7. bandwidthisdescribedin_B_A)BytespersecondB)BitspersecondC)megabitspermillisecondD)centimeters8. )_BIsaprotocolfortransferringafilefromoneh

5、osttoanotherhost.A.SMTP;B.FTP;C.TCP;D.UDP9. InTCP/IPstack,thetransportlayer'sflowcontrolmechanismusesA)slowstartB)congestionavoidanceC)threehand-shakingD)slidingwindow10. Comparedwithrdt2.0,thenewserviceinrdt3.0istoimplementthereliabledatatransferoverthechannelwithBA)biterrorB)datalossC)datatran

6、sferdelayD)congestion11. ICMPcontrolmessagesaretransferredinDdataunit.A)TCPB).UDPC).ARPD).IP12. ThereliabledatadeliverybetweenendsystemsisprovidedintheClayerofTCP/IParchitecture.A)networklayerB)datalinklayerC)transportlayerD)sessionlayer13. Whatisthemainfunctionofthenetworklayer?AA.node-to-nodedeliv

7、ery;B.process-to-processmessagedeliveryCsynchronization;D.updatingandmaintenanceofroutingtablesD.B)14. WhichIPaddressisineffectiveA)1C)15. IfIPaddressis6224,thensubnetprefixis_CA)0C)416. TheoutputportofarouterdonA) thephysicallay

8、erfunctionsC)networkmanagementB)D)24'tpC_ormfunctions.B) thedatalinklayerfunctionsD)buffermanagement17. Therearetwobroadclassesofpacket-switchednetworks:datagramnetworksandvirtual-circuitnetworks.datagramnetworksforwardpacketsintheirswitchesuse_B.B)IPaddressesA)MACaddre

9、ssesC)e-mailaddressesD)virtual-circuitnumbers18. .asshowbelow,whichtechnologyisn'ttypicalaccessnetworksCtechnongy.A)digitalsubscriberlineB)hybridfiber-coaxialcableC)circuitswitchingD)wirelessaccess19. Whichlayer-functionismostlyimplementedinanadapterNIC)?AA)physicallayerandlinklayerB)networklaye

10、randtransportlayerC)physicallayerandnetworklayerD)transportlayerandapplicationlayer20. AWhichdevicecan'tsolatethedepartmentalcollisiondomains.A)Hub;B)switch;C)router;D)AandB注：1试题字迹务必清楚,书写工整.此题4页,本页为第1页2题间不留空,一般应题卷分开教务处试题编号:3务必用A4纸打印三、填空题每空1分,共20分?1._protocolsdefineformat,orderofmessagessentandre

11、ceivedamongnetworkentities,andactionstakenonmessagetransmission,receipt.packetis2. Thetimerequiredtoexaminethepacketsheaderanddeterminewheretodirectthepartofthe_processingdelay.3. .Anynetworkthatforwardspacketsaccordingtohostdestinationaddressesa_datagramnetwork.4. WithintheInternetthemostimportantd

12、elaysthatpacketsufferedare_processingdelay,queuingdelay,_propagationdelay,and_transmissiondelay.5. Twoimportantnetwork-layerfunctioncanbeidentified:forwarding,routingNATtranstationtableWANsideLANside,500,33456. Alink-layeraddressisvariouslycalledalanaddress,orphysicaladdress,or_M

13、ACaddress.7. Twogenericformsofpipelinedreliabledatetransferprotocolsarego-Back-Nandselectiverepeat8. 10.AWebcachealsocalleda_proxy_server11.SupposeausersittinginahomenetworkbehindhostrequestsaWebpageonsomeWebserverPleaseaccordingtheNATtranslationtableattheNATrouter.Fillindatagramthatincludep

14、ortnumbersaswellasIPaddresse有IP缺端口号个扣0.5分)1. Thetop-downorderoftheInternetprotocolstackistheapplication,network,transport,link,physicallayers(F)2. Theinternet"sconnectionlessservicemakesprovisionforflowcontrolandcongestioncontrol(F)3. AnARPresponsesentwithinaframewithaspecificdestinationIPaddre

15、ss(F)4. linklayeraddressisLANaddress(T)5. Socketistheprogramminginterfacebetweentheapplicationlayerandthenetworklayer(F)6. Routinginvolvesallofanetwork(T)'srouters7. ForwardingtableisconfiguredbybothIntraandInter-ASroutingalgorithm(N)8. Anynetworkthatforwardspacketsaccordingtohostdestinationaddr

16、essesis/Cnetwork(F)9. HTTPismainlyapushprotocolandSMTPismainlyapullprotocol(N)10. Thebasicserviceoflinklayeristomoveanetwork-layerdatagramfromonenodteuterorhost)toanadjacentnode.(N)注：1试题字迹务必清楚,书写工整.此题4页,本页为第2页2题间不留空,一般应题卷分开教务处试题编号：3务必用A4纸打印y五、计算题(30points)1.considerthefollowingnetwork.Withtheindicat

17、edlinkcosts,useDijkstra-pathalgorithmtocomputetheshortestpathfromWtoallnetworknodes.10分t413vs351x3u4StepN,D(x),p(x)D(V),p(v)D(U),p(u)D(y),p(y)D(t),p(t)D(s),p(s)1W3,w1,w4,woooooo2wv3,w2,v4,v8,voow3wvu3,w4,v5,u7,u4wvux4,v5,u7,u5wvuxy5,u7,u6wvuxyt6,t7wvuxyts最短路径:WXWVWVYWVUWVUTWVUTS2. Suppose,theISPhave

18、beenallocatedtheaddressblock/24,nowiftheISPwantdivideitsaddressblockinto6equal-sizedsubnetaddressblocks,andeachsubnetcouldincluhosts.1) PleaseutilizeCIDRizedaddresses,determinethelengthofsubnetportionofaddress.(namely,howmanybitsshouldbeextend?(2points)2) Pleasewriteoutthesubnet#fsnetworkpre日x(2分)andsubnetmask.(办)3) Pleasewriteoutthesubnet#fsbroadcastaddress.(2)4) Pleasewriteoutthesubnet#fsrangeofhostaddress.2分)