计算机网络与通信期末考试B答案

四川考试试题（ 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：
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
A) slow start B) congestion avoidance
C) three hand-shaking D) sliding window 10．Comparedw ith 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
15 ． If IP address is 198.108.126.66224, then subnet prefix is _C
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 technongy. C
A) digital subscriber line fiber-coaxial cable
A) 198.108.126.60 B) 198.108.126.0 C) 198.108.126.64
D) 198.108.126.224
access networks
B) hybrid
C)
circuit
switching
D)wireless access
19 ．Which layer-function is mostly implemented in an adapter (NIC )?
domains.
本页为第
号：
务必用 A4 纸打印
三、填空题 （每空 1 分，共 20 分?）
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
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
Whichd evice can ' t isolate the departmental
collision A) Hub; B) switch;
C)
router;
D)
A and
注： 1 试题字迹务必清晰，书写工整。

本题 4 页，
题间不留空，一般应题卷分开
教务处试题编
1．_protocols
to direct the packet is part of the processing delay.
3． Any network that forwards packets according to host destination
4． Within the Internet the most important delays that packet suffered
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
requests a Web page on some Web server Please according the NAT translation table at the NAT router. Fill in datagram that include
port numbers as well as IP addresses. （有 IP 缺端口号一个扣 0.5
Dddr 分）
④
3345
1 分，共
10 分）
Dest addr=
判断S =题___（___每___
小__题__
S addr= _________
S addr= _________ D addr ________
D addr= _________
The top-down order
7
Interne t
10.0.0.4
addresses a _datagram
network.
are
processing
delay,
queuing
delay,
__propagation delay, and _transmission
delay.
5．Two important network-layer function
can be identified: forwarding NAT transtation table WAN side LAN side 138.76.29.7, 10.0.0.1, 5001
3345
6． A link-layer address is variously called a address,
or address,
or
7． Twog eneric forms of pipelined reliable date transfer protocols a re go-Back-N
and_ selective repeat
,
routing
lan physica
MAC address
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A
4 纸打印
五、计算题 (30 points)
1. consider the following network. With the indicated link costs, use Dijkst
10分
w
Step N '
D(x),p(x) D(V),p(v) D(U),p(u) D(y),p(y) D(t),p(t) D(s),
1 W
3,w
1,w
4,w ∞
∞
∞
2 wv 3,w
2,v
4,v 8,v ∞
3 wvu
3,w
4,v 5,u 7, 4 wvux
4,v
5,u 7, 5 wvuxy
5,u
7, 6
wvuxyt
6,
7 wvuxyts
最短路径： WX WV WVY WVU WVUT WVUTS
shortest-path algorithm to compute the shortest path from Wt o all network n s
2. Suppose, the ISP have been allocated the address block 197.2
3.18.0/24, now i
ISP want divide its address block into 6 equal-sized subnet address blocks, and subnet could include 28 hosts.
1) Please utilize CIDRized addresses, determine the length of subnet po of address.(namely, how many bits should be extend?(2 points ) #' s network prefix(2 分) and subnet
ma 分)
3) Please write out the subnet 1 4) Please write out the subnet 1
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 A
4 纸打印
2) Please write out the subnet 1 #'s broadcast address.(2 分 )
#'s range of host a ddress. (2 分)
注： 1 试题字迹务必清晰，书写工整
本题 4 页，
注： 1 试题字迹务必清晰，书
本题 4 页，写工整
本页为第 4 页
教务处试题编
2 题间不留空，一般应题卷分
开
号：
3 务必用A
4 纸打印。