计算机网络与通信期末考试B答案

1、大学期考试试题（B）闭卷（200820W第2学期）课程号：课序号：07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：考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考试，必须严格执行四川大学考试工作管理办法和四川大学考场规则有考试违纪作弊行为的，一律按照四川大学学生考试违纪作弊处罚条例进行处理。四川大学各级各类考试的监考人员，必须严格执行四川大学考试工作管理办法、四川大学考场规则和四川大学监考人员职责有违反学校有关规定的，严格按照四J11大学教学事故认定及处理办法进行处理。第一题第二题第三题第四题第五题卜总分一、英译汉（10分）ISPIN

2、TERT服务供应商2.NIC网络接口卡3.DNS域名服务系统4.MAC介质接入控制5BGP边界网关协议6.MSS最大数据段尺寸7.FTP文件传输协议8MPLS多协议标签交换9AS自治系统1O.packetswitching分组交换:、单项选择题（每小题I.5分，共30分）Werefertothelink-layerpacketsasDC. datagrams D. framesA.messagesB.segmentsTheIPprotocolliesinCA.applicationlayerB.transportlayerC.networklayerD.linklayerAisaCircuit

3、-switchednetwork.A.TDMB.DatagramnetworkC.InternetD.virtualcircuitnetworkThepacketexperiencesaBdelayasitwaitstobetransmittedontothelink.A.processingdelayB.queuingdelayC.propagationdelayD.transmissiondelayDWhichthefollowingprotocolsdoesnotuseTCP/IPasitsunderlyingprotocols?A.SMTP;B.FTP;C.TELNET;D.TFTPW

4、hatisusedtospecifyplacementoftext,filesandobjectsthataretobetransferredfromthewebservertotheclient?BA.HTTPB.HTMLC.HDLCD.AlloftheabovebandwidthisdescribedinBA)BytespersecondB)BitspersecondC)megabitspermillisecondD)centimeters)_BIsaprotocolfortransferringafilefromonehosttoanotherhost.A. SMTP; B.FTP;C.

5、TCP;D. UDPInTCP/IPstack,thetransportlayers flow control mechanisBA)slowstartB)congestionavoidaneeC)threehand-shakingD)slidingwindowComparedwithrdt2.0,thenewserviceinrdt3.0istoimplementthereliabledatatransferoverthechannelwithBA)biterrorB)datalossC)datatransferdelayD)congestionICMPcontrolmessagesaret

6、ransferredinDdataunit.A)TCPB).UDPC).ARPD).IPThereliabledatadeliverybetweenendsystemsisprovidedintheClayerofTCP/IParchitecture.A)networklayerB)datalinklayerC)transportlayerD)sessionlayerWhatisthemainfunctionofthenetworklayer?AA.node-to-nodedelivery;B.process-to-processmessagedeliveryD.updati ng andsy

7、nchronization;maintenanceofroutingtablesB)B) D) 24 t perform functions.WhichIPaddressisineffectiveDA)1C)ifipaddressis6224,thensubnetprefixis_CA)0C).theoutputportofarouterdonA)thephysicallayerfunctionsB)thedatalinklayerfunctionsC)networkmanagementD)buffermanagement.therearetwobroadclassesofpacket-swi

8、tchednetworks:datagramnetworksandvirtual-circuitnetworks.datagramnetworksforwardpacketstheirswitchesuseBA)MACaddressesC)e-mailaddresses.asshowbelow,whichtechnologyisntechnongy.Cdigitalsubscriberlinefiber-coaxialcableIPaddressesD)virtual-circuitnumbersttypicalaccessnetworksB)hybridC)circuitswitchingD

9、)wirelessaccessWhichlayer-functionismostlyimplementedinanadapter(NICA_A)physicallayerandlinklayerB)networklayerandtransportlayerC)physicallayerandnetworklayerD)transportlayerandapplicationlayerAWhichdevicecantisolatethedepartmentalcollisiondomains.A)Hub;B)switch;C)router;D)AandB注：1试题字迹务必清晰，书写工整。本题4页

10、，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?)_protocolsdefineformat,orderofmessagessentandreceivedamongnetworkentities,andactionstakenonmessagetransmission,receipt.Thetimerequiredtoexaminethepacketsheaderanddeterminewheretodirectthepacketispartoftheprocessingdelay.Anynetworkthatforwardspac

11、ketsaccordingtohostdestinationaddressesa_datagramnetwork.WithintheInternetthemostimportantdelaysthatpacketsufferedare_processingoutingdelay,queuingdelay,_propagation.delay,and_transmission,delay.5.Twoimportantnetwork-layerfunctioncanbeidentified:forwarding6.Aaddress,or.physiaddress,or_MACaddress.and

12、selectiverepeat8.10.AWebcachealsocalleda_proxyserver7.Twogenericformsofpipelinedreliabledatetransferprotocolsarego-Back-N11.SupposeausersittinginahomenetworkbehinchostrequestsaWebpageonsomeWebserverPleaseaccordingtheNATtranslationtableattheNATrouter.Fillindatagramthatinclude3345判断题（每小题1分，t10分）DddrTh

13、etop-downorderoftheinternDestaddr=0.0.4addr=addr=TheinternetscohnectionlessservicemakesprovisionforflbwcontrolportnumbersaswellasIPaddresses(有IP缺端口号个扣0.5分)andcongestioncontrol(F)3.他ARPresponsesentwithinaframewithaspecificdestinationIPaddress(F)linklayeraddressislanaddress(t)heSocketistheprogrammingi

14、nterfacebetweentheapplicationlayerandtnetworklayer(F)Routinginvolvesallofanetwork(T)sroutersForwardingtableisconfiguredbybothIntraandInter-ASroutingalgorithm(N)esAnynetworkthatforwardspacketsaccordingtohostdestinationaddressisaVCnetwork(F)HTTPismainlyapushprotocolandSMTPismainlyapullprotocol(N)Theba

15、sicserviceoflinklayeristomoveanetwork-layerdatagramfromonenode(routerorhost)to本题4教务处anadjacentnode.(N)注：1试题字迹务必清晰，书写工整。页，本页为第2页2题间不留空，一般应题卷分开试题编号：3务必用A4纸打印五、计算题(30points)considerthefollowingnetwork.Withtheindicatedlinkcosts,useDijkstrashortest-pathalgorithmtocomputetheshortestpathfromWtoallnetworkno

16、des.10分twStepND(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,voo3wvu3,w4,v5,u7,u4wvux4,v5,u7,u5wvuxy5,u7,u6wvuxyt6,t7wvuxyts最短路径：WXWVWVYWVUWVUTWVUTSSuppose,theISPhavebeenallocatedtheaddressblock/24,nowiftheISPwantdivideitsaddressblockinto6equal-sizedsubnetaddres

17、sblocks,andeachsubnetcouldinclude28hosts.PleaseutilizeCIDRizedaddresses,determinethelengthofsubnetportionofaddress.(namely,howmanybitsshouldbeextend?(2points)Pleasewriteoutthesubnet1#snetworkprefix(2分)andsubnetmask.(2分)Pleasewriteoutthesubnet#sbroadcastaddress.(分)4) Please write out the sub net #s range of hostaddress. (2 分)注：1试题字迹务必清晰，