计算机网络与通信期末考试B精选答案.docx

1、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）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：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，严格按照四川大学教学事故认定及处理办法进行处理。第

2、一题第二题第三题第四题第五题总分一、英译汉（10分）1. ISP INTERT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 8 MPLS多协议标签交换9 AS自治系统10. packet switching 分组父换二、单项选择题（每小题1. 5分，共30分）1 We refer to the link-layer packets as D2 The IP protocol lies in CA. applicati on layer B. tran sport layer

3、C n etwork layer Dlink layer3. A is a Circuit-switched n etworkA. TDM B. Datagram net work C I nternet D vir tualcircuit n etwork4 The packet experiences a B delay as it waits to be transmitted onto the linkA. process ing delay B. queu ing delay C propagatio n delayD. tran smissi on delay5 DWhich th

4、e following protocols does not use TCP/IP as its underlying protocols?A. SMTP; B. FTP; C. TELNET; D. TFTP6.What is used to specify placement of text, files and objects thatare to be tra nsferred from the web server to the die nt? BA. HTTP B. HTML C. HDLC D. All of theabove7 bandwidth is described in

5、 _B_A)Bytes per sec ond B) Bits per sec ondC) megabits per millisec ond D) cen timeters8 )_B Is a protocol for transferring a file from one host to anotherhos t.A. SMTP; B. FTP; C. TCP; D. UDP9 In TCP/IP stack, the transport layer s flow control mechanism uses BC) three han d-shak ing D) slidi ng wi

6、n dow10 Compared with rdt20, the new service in rdt3. 0 is to imp1ement the reliable data tran sfer over the cha nnel with BA)bit error B) data loss C) data tran sfer delay D)con gesti on11 ICMP control messages are transferred in D data unitA) TCP B). UDP C). ARP D). IP12 The reliable data delivery

7、 between end systems is provided in theC layer of TCP/IP architecture.sessi on layer13 What is the main function of the network layer?B. process-to-processA. node-to-node delivery;message deliveryC syn chro ni zati on; D.updat ing and maintenance of routi ng tables14 Which IP address is in effective

8、 D C) 192. 168. 0. 215 If IP address is 198 108 126.66224, then sub net prefix is _CA) 198. 108. 126. 60B)198. 108. 126. 0C)198. 108. 126. 64D)198. 108. 126. 22416 The out put port of a router dont perform _ Cfunctions.A) the physical layer fun cti ons fun cti onsB) the data link layerC) n etwork ma

9、n ageme ntD) buffer man ageme nt17 There are two broad classes of packetswitched networks: datagramnetworks and virtual-circuitnetworks datagram networks forward packetsin their switches use BA) MAC addressesB) IP addressesC) e-mail addressesD) virtual-circuit nu mbers18 as show below, which tech no

10、 logy isn t typical access n etworks tech non gy. CA)digital subscriber lineB) hybridfiber-coaxial cableC) circuit switch ingD)wirelessaccess19 Which layer-function is mostly implemented in an adapter(NIC)A) physical layer and link layerB) n etwork layer andtran sport layerC) physical layer and netw

11、ork layer D)transport layer andapplicatio n layer20 A Which device can t isolate the departmentalcollisiondoma ins.A) Hub; B) switch; C) router; D) A and B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. _protocols define format, order of messages sent and receivedamongn

12、etwork entities, and actions taken on message transmission, receipt.2. The time required to examine the packet s header and determine whereto direct the packet is part of the _processing delay.3.that forwards packets according to host destinationa _datagram n etworkAny network addresses4. Within the

13、 Internet the most important delays that packet suffered are.processing delay, queu ing delay, _ ropagation delay, and -transmission delay.5.identified: forwardingTwoimportant network-layer functioncan be,rout ing 6. A link-layer address is variously called a _lan address, orphysical address, or _MA

14、C address.7.Two gen eric forms of pipeli ned reliable date tran sfer protocols are _go-Back-N and_ selective :repeat 8. 10. A Web cache also called a_proxy_server .11. Suppose a user sittingin a home network behind host 10. 0.0.1 requests3. An ARPresponse sent within a frame with a specific destinat

15、ion IP address (F)4. link layer address is LAN address (T)5. Socket is the program ming in terface betwee n the applicati on layer and the n etwork layer (F)6. Routing involves all of a network s routers (T)7. Forward ing table is con figured by both Intra and In terAS rout ing algorithm (N)8. Any n

16、etwork that forwards packets according to host destination addresses is a VC n etwork (F)9. HTTP is mainly a push protocol and SMTP is mainly a pull protocol (N)10. The basic service of link layer is to movea network-layer datagram from one node krouter or host ) to anadjace nt no de. (N)本题4页，本教务处试题

17、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(30 points)1 consider the following n etwork. With the indicated link costs, use Dijkstra shortest-path algorithm to compute the shortest path from W to all network node 10分UlStepD(x), p(x)D(V),p (v)D(U),p (u)D(y),p(y)D(t), p(t)D(s), p(s1W3, w1,

18、w4, w0000002WV3, w2,v4,v8,v003WVU3, w4,v5, u7, u4wvux4,v5, u7, u5wvuxy5, u7, u6wvuxyt6, t7wvuxyts最短路径：WX WV WVY WVU WVUT WVUTS2. Suppose, the ISP have been allocated the address block 197 23. 18. 0/24, now if t ISP want divide its address block into 6 equal-sized sub net address blocks, and ea sub n

19、et could in elude 28 hosts.on1) Please utilize CIDRized addresses, determ ine the len gth of sub net portiaddress(namely, how many bits should be exte nd? (2 points )2)Please writeoutthesubnetn etwork prefix (2分)and sub net mask3)4)分）Please writePlease writeoutoutthesubnetbroadcast address(2分）thesub

20、netrange of host address.（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33. Suppose the gen era tor polyno mial is x+ 1, data bits to be sent D is ,what is the CRC bits? Please write the whole compute course 10答案：The gen erator bits G=1001, r=3rR = rema in derD*2/GCRC bits is Oil3务必用A4纸打印