计算机网络与通信期末考试B精选答案.docx
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计算机网络与通信期末考试B精选答案
大学期
考试试题(B)闭卷
(2008——2009学年第2学期)
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计算机网络与通信任课教师:
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第一题
第二题
第三题
第四题
第五题
总分
一、英译汉(10分)
1.ISPINTERT服务供应商2.NIC网络接口卡3.DNS域名服务系
统4.MA(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10.packetswitching分组父换
二、单项选择题(每小题1.5分,共30分)
1•Werefertothelink-layerpacketsasD
2•TheIPprotocolliesinC
A.applicationlayerB.transportlayerC・networklayerD
linklayer
3.AisaCircuit-switchednetwork・
A.TDMB.DatagramnetworkC・InternetD・virtual
circuitnetwork
4•ThepacketexperiencesaBdelayasitwaitstobetransmittedontothelink・
A.processingdelayB.queuingdelayC・propagationdelay
D.transmissiondelay
5・DWhichthefollowingprotocolsdoesnotuseTCP/IPasitsunderlyingprotocols?
A.SMTP;B.FTP;C.TELNET;D.TFTP
6.Whatisusedtospecifyplacementoftext,filesandobjectsthat
aretobetransferredfromthewebservertothedient?
B
A.HTTPB.HTMLC.HDLCD.Allofthe
above
7•bandwidthisdescribedin_B_
A)BytespersecondB)Bitspersecond
C)megabitspermillisecondD)centimeters
8・)_BIsaprotocolfortransferringafilefromonehosttoanother
host.
A.SMTP;B.FTP;C.TCP;D.UDP
9•InTCP/IPstack,thetransportlayersflowcontrolmechanismusesB
C)threehand-shakingD)slidingwindow
10•Comparedwithrdt2・0,thenewserviceinrdt3.0istoimp1ementthereliabledatatransferoverthechannelwithB
A)biterrorB)datalossC)datatransferdelayD)
congestion
11•ICMPcontrolmessagesaretransferredinDdataunit・
A)TCPB).UDPC).ARPD).IP
12•Thereliabledatadeliverybetweenendsystemsisprovidedinthe
ClayerofTCP/IParchitecture.
sessionlayer
13•Whatisthemainfunctionofthenetworklayer?
B.process-to-process
A.node-to-nodedelivery;
messagedelivery
Csynchronization;D.updatingandmaintenanceofroutingtables
14•WhichIPaddressisineffectiveD
C)192.168.0.2
15•IfIPaddressis198・108・126.66224,thensubnetprefixis_C
A)198.108.126.60
B)198.108.126.0
C)198.108.126.64
D)198.108.126.224
16•Theoutputportofarouterdon
tperform_C
functions.
A)thephysicallayerfunctionsfunctions
B)thedatalinklayer
C)networkmanagement
D)buffermanagement
17•Therearetwobroadclassesofpacket~switchednetworks:
datagram
networksandvirtual-circuit
networks・datagramnetworksforwardpackets
intheirswitchesuseB
A)MACaddresses
B)IPaddresses
C)e-mailaddresses
D)virtual-circuitnumbers
18•・asshowbelow,whichtechnologyisn'ttypicalaccessnetworkstechnongy.C
A)
digitalsubscriberline
B)hybrid
fiber-coaxialcable
C)circuitswitching
D)wireless
access
19•Whichlayer-functionismostlyimplementedinanadapter
(NIC)
A)physicallayerandlinklayer
B)networklayerand
transportlayer
C)physicallayerandnetworklayerD)
transportlayerand
applicationlayer
20•AWhichdevicecantisolatethedepartmental
collision
domains.
A)Hub;B)switch;C)router;D)AandB
注:
1试题字迹务必清晰,书写工整。
页为第1页
2题间不留空,一般应题卷分幵
3务必用A4纸打印
本题4页,本
教务处试题编号:
三、填空题(每空1分,共20分
1._protocolsdefineformat,orderofmessagessentandreceived
amongnetworkentities,andactionstakenonmessagetransmission,receipt.
2.Thetimerequiredtoexaminethepacketsheaderanddeterminewhere
todirectthepacketispartofthe_processingdelay.
3.
thatforwardspacketsaccordingtohostdestination
a_datagramnetwork・
Anynetworkaddresses
4.WithintheInternetthemostimportantdelaysthatpacketsufferedare
.processingdelay,queuingdelay,__ropagation
delay,and-transmissiondelay.
5.
identified:
forwarding
Twoimportantnetwork-layerfunction
canbe
routing
6.Alink-layeraddressisvariouslycalleda_lanaddress,or
physicaladdress,or_MACaddress.
7.Twogenericformsofpipelinedreliabledatetransferprotocolsare_
go-Back-Nand_selective:
repeat
8.10.AWebcachealsocalleda
_proxy_server.
11.Supposeausersitting
inahomenetworkbehindhost10.0.0.1requests
3.AnARPresponsesentwithinaframewithaspecificdestinationIPaddress(F)
4.linklayeraddressisLANaddress(T)
5.Socketistheprogramminginterfacebetweentheapplicationlayerandthenetworklayer(F)
6.Routinginvolvesallofanetworksrouters(T)
7.ForwardingtableisconfiguredbybothIntraandInter~ASroutingalgorithm(N)
8.AnynetworkthatforwardspacketsaccordingtohostdestinationaddressesisaVCnetwork(F)
9.HTTPismainlyapushprotocolandSMTPismainlyapullprotocol(N)
10.Thebasicserviceoflinklayeristomoveanetwork-layerdatagramfromonenodekrouterorhost)toan
adjacentnode.(N)
本题4页,本
教务处试题编号:
注:
1试题字迹务必清晰,书写工整。
页为第2页
2题间不留空,一般应题卷分幵
3务必用A4纸打印
五、计算题(30points)
1・considerthefollowingnetwork.Withtheindicatedlinkcosts,useDijkstrashortest-pathalgorithmtocomputetheshortestpathfromWtoallnetworknode10分
Ul
Step
D(x),p(x)
D(V),p(v)
D(U),p(u)
D(y),p(y)
D(t),p(t)
D(s),p(s
1
W
3,w
1,w
4,w
00
00
00
2
WV
3,w
2,v
4,v
8,v
00
3
WVU
3,w
4,v
5,u
7,u
4
wvux
4,v
5,u
7,u
5
wvuxy
5,u
7,u
6
wvuxyt
6,t
7
wvuxyts
最短路径:
WXWVWVYWVUWVUTWVUTS
2.Suppose,theISPhavebeenallocatedtheaddressblock197・23.18.0/24,nowiftISPwantdivideitsaddressblockinto6equal-sizedsubnetaddressblocks,andeasubnetcouldinelude28hosts.
on
1)PleaseutilizeCIDRizedaddresses,determinethelengthofsubnetporti
address・(namely,howmanybitsshouldbeextend?
(2points)
2)
Pleasewrite
out
the
sub
net
networkprefix(2
分)andsubnetmask
3)
4)
分)
Pleasewrite
Pleasewrite
out
out
the
sub
net
broadcastaddress・(2
分)
the
sub
net
rangeofhostaddress.
(2分)
注:
1试题字迹务必清晰,书写工整
本题4页,本
页为第3页
2题间不留空,一般应题卷分幵
教务处试题编号:
3务必用A4纸打印
3
3.Supposethegeneratorpolynomialisx
+1,databitstobesentDis,
whatistheCRCbits?
Pleasewritethewholecomputecourse・10
答案:
ThegeneratorbitsG=1001,r=3
r
R=remainder[D*2
/G]
CRCbitsisOil
3务必用A4纸打印