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：

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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. 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 D

2	A. messages	B. segme nts	B. tran sport layer	C? datagrams	D. frames
	? The IP protocol lies in	C			C? n etwork layer D
	A. applicati on layer

linklayer

3. A is a Circuit-switched n etwork?

A. TDM

B. Datagram net work

C? I nternet

D? vir tual

circuitn etwork

4?The packet experiences a B delay as it waits to be transmitted ontothe link?

A. process ing delay

B. queu ing delay

C? propagatio n

delay

D.tran smissi on delay

5?DWhichthe following protocols does not use TCP/IP as its underlyingprotocols?

A.SMTP; B. FTP; C. TELNET; D. TFTP

6.What is used to specify placement of text, files and objects that

areto be tra nsferred from the web server to the die nt? B

A. HTTP

B. HTML C. HDLC

D.

All of the

above

7?bandwidth is described in _B_

A)Bytes per sec ond B)Bits per sec ond

C)megabits per millisec ond D)cen timeters

afile 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

A)slow start B)con gesti on avoida nee

C)three han d-shak ing D) slidi ng win dow

10 ?Compared with rdt2?0,the new service in rdt3. 0 is to imp1ement the reliable data transfer over the cha nnel with B

A)bit error

B) data loss

C) data tran sfer delay

D)

congesti on

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

Clayer of TCP/IP architecture.

A) n etwork layer

B) data link layer

C) tran sport layer

D)

session layer

13 ?What is the main function of the network layer?

A. node-to-node

delivery;

B. process-to-process

messagedelivery

Csyn chro ni zati on; D.updating and maintenance of routi ng tables

14 ?Which IP address is in effective______________________D_____

C)192. 168. 0. 2

15 ?If IP address is 198?108?126.66224,then sub net prefix is _C

A)198. 108. 126. 60 B)198. 108. 126. 0

C)198. 108. 126. D)198. 108. 126. 224

16 ? The out put port of a router don	t perform _ C	B) the data link layer	functions.
A) the physical layer fun cti ons fun cti ons

C)n etwork man ageme nt D)buffer man ageme nt

17? There are two broad classes of packet~switched networks: datagram

networksand virtual-circuit networks?datagramnetworks forward packets

intheir switches use B

A) MAC addresses	D) virtual-circuit nu mbers	B) IP addresses
C) e-mail addresses

18	?	? as show below, which tech no logy isn ' t typical access n etworks tech non gy. C	B) hybrid
	A)	digital subscriber line

fiber-coaxialcable

C)circuit switch ing D)wireless

access

19

? Which layer-function is mostly implemented in an adapter

(NIC)

A) physical layer and link layer B) n etwork layer and tran sport 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

本题4页，本

注：1试题字迹务必清晰，书写工整。

页为第1页

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2 题间不留空，一般应题卷分幵

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 sentand received

amongnetwork entities,

and actions taken on message transmission,

receipt.

2.The time required to examine the packet s header and determine where

todirect the packet is part of the _processing_______________________________________ delay.

3.Any network

thatforwards packets according to host destination addresses

a_datagram _____________________n etwork?

4.Within the Internet the most important delays that packet sufferedare

.processing_____________________delay, queu ing delay, __ ropagation_______________________________________

delay,and -transmission _____________________________delay.

5.

Twoimportant 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. Twogen 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 sitting ina home network behind host 10. 0.0.1 requests

accordingthe XATtranslation table at the NAT router.

portnumbers as well as IP addresses?(有IP缺丫而

口号一个扣0.5分）

345

10.The basic service of link layer is to movea network-layer datagramfrom one node krouter or host ) to an

adjacent no de. (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

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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：WXWV WVY WVU WVUT WVUTS

2.Suppose, the ISP have been allocated the address block 197?23.18. 0/24, now if t ISP want divide its address block into 6equal-sized sub net address blocks,

andea sub net could in elude 28 hosts.

1)Please utilize CIDRized addresses, determ ine the len gth of sub netporti on

address?(namely,how many bits should be exte nd? (2 points )

2)

Please write

out

the

sub net

n etwork prefix (2

分)and sub net mask

分

）

3)

Please write

out

the

sub

net

broadcast address?(2

分

）

4)	Please write	out	the	sub net	range of host address.	本题4页，本	（2
							分）
注：1试题字迹务必清晰，书写工整

页为第3页

3

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