（2008 ——2009 学年第 2 学期）
课程号：30306230 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。 第一题 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. MAC介质接入控制 5 BGP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分组交换 二、单项选择题 （每小题l. 5分，共30分) 1．We refer to the link-layer packets as D A. messages B. segments C. datagrams D. frames 2．The IP protocol lies in C A. application layer B. transport layer C. network layer D. link layer 3． A is a Circuit-switched network. A. TDM B. Datagram network C. Internet D. virtual circuit network 4．The packet experiences a B delay as it waits to be transmitted onto the link. A. processing delay B. queuing delay C. propagation delay D. transmission delay 5．DWhich the following protocols does not use TCP/IP as its underlying protocols? A. SMTP; B.FTP; C.TELNET; D.TFTP 6．What is used to specify placement of text, files and objects that are to be transferred from the web server to the client? B A. HTTP B.HTML C.HDLC D. All of the above 7．bandwidth is described in _B__ A) Bytes per second B) Bits per second C) megabits per millisecond D) centimeters 8．) _B___ Is a protocol for transferring a file from one host to another host. A. SMTP; B.FTP; C.TCP; D. UDP 9．In TCP/IP stack, the transport layer’s flow control mechanism uses B 第二题 第三题 第四题 第五题 总分 A) slow start B) congestion avoidance C) three hand-shaking D) sliding window 10．Compared with rdt2.0, the new service in rdt3.0 is to implement the reliable data transfer over the channel with B A)bit error B) data loss C) data transfer delay D) congestion 11．ICMP control messages are transferred in D data unit. A) TCP B).UDP C).ARP D).IP 12．The reliable data delivery between end systems is provided in the C layer of TCP/IP architecture. A) network layer B) data link layer C) transport layer D) session layer 13．What is the main function of the network layer? ___A______ A. node-to-node delivery; B. process-to-process message delivery C synchronization; D.updating and maintenance of routing tables 14．Which IP address is ineffective ___D___. A) 202.131.45.61 B) 127.0.0.1 C) 192.168.0.2 D) 290.25.135.12 15．If IP address is 198.108.126.66, subnet mask is 255.255.255.224, then subnet prefix is _C___. A) 198.108.126.60 B) 198.108.126.0 C) 198.108.126.64 D) 198.108.126.224 16．The output port of a router don’t perform __C____ functions. A) the physical layer functions B) the data link layer functions C) network management D) buffer management 17．There are two broad classes of packet-switched networks: datagram networks and virtual-circuit networks. datagram networks forward packets in their switches use __B____. A) MAC addresses B) IP addresses C) e-mail addresses D) virtual-circuit numbers 18．.as show below, which technology isn’t typical access networks technongy. C A) digital subscriber line B) hybrid fiber-coaxial cable C) circuit switching D)wireless access 19．Which layer-function is mostly implemented in an adapter（NIC）? _A_________ A) physical layer and link layer B) network layer and transport layer C) physical layer and network layer D) transport layer and application layer 20．__A______Which device can’t isolate the departmental collision domains. A) Hub; B) switch; C) router; D) A and B 注：1试题字迹务必清晰，书写工整。 本题 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．_protocols_______ define format, order of messages sent and received among network entities, and actions taken on message transmission, receipt. 2．The time required to examine the packet’s header and determine where to direct the packet is part of the __processing_________delay. 3．Any network that forwards packets according to host destination addresses a _datagram_________ network. 4．Within the Internet the most important delays that packet suffered are _processing_________ delay, queuing delay, __propagation____________ delay, and _transmission__________ delay. 5．Two important network-layer function can be identified: forwarding ___ __ , routing ____ . 6．A link-layer address is variously called a _lan_______address, or _physical_______address, or _MAC_______address. 7．Two generic forms of pipelined reliable date transfer protocols are _ go-Back-N __________ and_ selective repeat ___________ 8．10．A Web cache also called a _proxy__server__ ___. 11．Suppose a user sitting in a home network behind host 10.0.0.1 NAT transtation table requests a Web page on some Web server (port 80) with IP address WAN side LAN side 202.119.30.156, Please according the NAT translation table at the NAT 138.76.29.7, 5001 10.0.0.1, 3345 router. Fill in datagram that include port numbers as well as IP …… …… addresses.（有IP缺端口号一个扣0.5分 ） Source addr=10.0.0.1,3345 Dest addr=128.119.40.186,80 S =138.76.29.7,5001_____________ Dddr=128.119.40.186,80____________ ① 10.0.0.4 138.76.29.7 ④ S addr=_128.119.40.186,80____________ S addr=128.119.40.186,80____________ D addr=_138.76.29.7,5001____________ D addr=_10.0.0.1,3345__________ 四、判断题（每小题1分，共10分） 1．The top-down order of the Internet protocol stack is the application, network, transport, link, physical layers (F) 2．The internet’s connectionless service makes provision for flow control and congestion control (F) 3．An ARP response sent within a frame with a specific destination IP address (F) 4．link layer address is LAN address (T) 5．Socket is the programming interface between the application layer and the network layer (F) 6．Routing involves all of a network’s routers (T) 7．Forwarding table is configured by both Intra and Inter-AS routing algorithm (N) 8．Any network that forwards packets according to host destination addresses is a VC network (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 move a network-layer datagram from one node（router or host）to an adjacent node. (N) 注：1试题字迹务必清晰，书写工整。 本题 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 五、计算题 (30 points) 1. consider the following network. With the indicated link costs, use Dijkstra’s shortest-path algorithm to compute the shortest path from W to all network nodes. 10分 t 4 1 7 4 y 3 3 v s 3 1 5 x 1 u 3 4 w Step 1 2 3 4 5 6 7 N’ D(x),p(x) D(V),p(v) D(U),p(u) D(y),p(y) D(t),p(t) D(s),p(s) 3,w 3,w 3,w 1,w 4,w 2,v ∞ 4,v 4,v 4,v ∞ 8,v 5,u 5,u 5,u ∞ ∞ 7,u 7,u 7,u 6,t W wv wvu wvux wvuxy wvuxyt wvuxyts 最短路径：WX WV WVY WVU WVUT WVUTS 2. Suppose, the ISP have been allocated the address block 197.23.18.0/24, now if the ISP want divide its address block into 6 equal-sized subnet address blocks, and each subnet could include 28 hosts. 1) Please utilize CIDRized addresses, determine the length of subnet portion of address.(namely, how many bits should be extend?(2 points ) 2) Please write out the subnet 1#’s network prefix(2分) and subnet mask.(2分) 3) Please write out the subnet 1#’s broadcast address.(2分) 4) Please write out the subnet 1#’s range 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，一般应题卷分开 教务处试题编号： 3务必用A4纸打印 3. Suppose the generator polynomial is x3+ 1, data bits to be sent D is 101110000, what is the CRC bits? Please write the whole compute course. 10分 答案： The generator bits G=1001, r=3 R = remainder[D*2 r /G] CRC bits is 011 注：1试题字迹务必清晰，书写工整。 本题 4 页，本页为第 4 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
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