-
注意:这是
04-05
学期王老师出的试题。<
/p>
1
.
Ethe
rnet
使用的
MAC
协议是(
1
)。当发生冲突时,将进入二进制指数退避阶
段,对于第
3
次冲突,等待重传的最长时间是
512
位时间的(
2
)倍。<
/p>
(
1
)
A
.
ALOHA
(
2
)
A
.<
/p>
1
B
p>
.
CSMA/CD
B
.
3
C
.
CSMA/CA
C
.
5
D
.
CSMA/DD
D
.
7
2<
/p>
.网络体系结构定义计算机网络的分层结构,
TCP/IP
模型和
ISO/OSI
参考模型是
两个主要的网络模型,其中
TCP/IP
协议传送
层之上的层是(
3
)层,而
ISO/O
SI
则是一个
(
4
)
层的模型。
(
3
)
A
.应用
(
4
)
A
.
4
B
.表述
B
.
5
C
.会话
C
.
6
D
.网络
D
.
7
3<
/p>
.传统的以太网传输介质是同轴电缆,其中使用粗同轴电缆的网络称为(
< br>5
)网
络,使用细同轴电缆的网络称为(
6
)网络。
10Base-T
网络使用的传输介质是无
屏蔽双绞线,简称为
(
7
)。
<
/p>
(
5
)
A
.
5BASE
(
6
)
A
.
p>
5BASE
(
7
)
A
.
UP
T
B
.
10BASE-10
B
.
10BASE-10
B
.
UTP
p>
C
.
10BASE-5
C
.
10BASE-5
C
.
UPP
D
.
10BASE-2
D
.
10BASE-2
D
.
UUP
4
.有
N
个节点共享一条总传输速率为
R
的通信信道,若采用
TDMA
协议,则每个
节点的平均传输速率是
(
8
)
,而瞬时传输速率则为
(
9
);如果采用
FDMA
协议,则每个节点的平均传输为
(
1
0
),而瞬时传输速率则为
(
11
)
。
(
8
p>
)
A
.
R
(
9
)
p>
A
.
R
(
10
)
A
.
R
(
11
)
A
.
R
B
.
R/N
B
.
R/N
B
.
R/N
B
.
R/N
C
.
NR
C
.
NR
C
.
NR
C
.
NR
D
.
2R
D
.
2R
D
.
2R
D
.
2R
5
.可靠传输协议
rdt3.0
的发送和
接收窗口都是
1
,对其进行改进后的
G
BN
协议和
SR
协议都把发送窗口尺寸
扩大为
N
(
>1
)。但
GBN
协议的接收窗口为(
1
2
),而
SR
协议的接收窗口为(
p>
13
)。对
SR
协
议,若使用
k
位的序号,则其发送窗口尺寸
应
(
14
)
。
(
12<
/p>
)
A
.
1
(
13
)<
/p>
A
.
1
B
.
N/4
B
.
N/4
C
.
N/2
C
.
N/2
D
.
N
D
.
N
p>
D
.等于
2
k-1
(
14
)<
/p>
A
.不大于
2
k
B
.等于
2
k
1 <
/p>
C
.不大于
2
k
-1
6
.
P
PP
协议可以用在(
15
)
链路上,并使用
(<
/p>
16
)协议完成链路状态的管理,使
用<
/p>
(
17
)协议
完成网络层地址配置和压缩方式协商。
(
15
)
A
.多点对多点
(
16
)
A
.
CNP
(
17
)
A
.
CNP
B
.点对点
B
.
PLC
B
.
PLC
C
.点对多点
C
.
LCP
C
.
LCP
D
.任何
D
.
NCP
D
.
NCP
7
.
RTP
协议和
RTCP
协议是
TCP/IP
协议
的(
18
)层的扩充子层,
H.323
是
(
19
)
层协议。
(
18
)
A
.
应用层
(
19
)
A
.应用层
B
.传送层
B
.传送层
C
.网络层
C
.网络层
D
.链路层
D
.链路层
8
.在以太网中,增加帧的尺寸将使信道利用率
(
20
)。
(
20
)
A<
/p>
.提高
B
.降低
C
.保持恒定
D
.无法断定
二、
Match the following tasks
to one of the TCP/IP layers: (10%)
1.
Route
determination
(
网络层
)
2.
Transmission
of
Segment
3.
ASCII changed to EBCDIC
(
运输层
)
(
链路层
)
4.
Frame defined
(
链路层
)
5.
Transmission of data frame
(
链路层
)
6.
Provides log-
in and logout procedures
(应用程
)
7.
Selects a destination network
8.
Provides services for the network
applications
(
网络层
)
(
应用层
)
9.
Reliable end-to-end data transmission
(运输层
)
10.
Provides
E-mail and file transfer services
(
应用程
)
三、
Answer the following
questions (20%)
:
(
1
)
Please show an
example for every IP V4 address classes. (5%)
?
A
类地址范围
(0.0.0.0
----127.255.255.255)
?
B
类地址范围
(128.0.0.0
----191.255.255.255)
?
C
类地址范围
(192.0.0.0
----223.255.255.255)
?
D
类地址范围
(224.0.0.0
----239.255.255.255)
?
E
类地址范围
(240.0.0.0
----255.255.255.255)
(
2
)
Consider IP address
202.203.208.68 . What are the broadcast address
and network
2
address when default network mask is
used? (5%)
broadcast address
:202.203.208.255
network address
:202.203.208.0
(
3
)
What are the format and example of
IPv6 address?(5%)
(4)
Consider plain text
“
thisisatest
”
, and the
Caesar cipher of k=4 is used. What is the
Cipher text after encrypting? (5%)
四、
Complete follow problems.
(35%)
1.
Suppose
we want to transmit the message 10101001 and
protect it from errors using
the
CRC
generator
x
3
+1. Use
long
division
to
determine
the
message
that
should
be
transmi
tted.
(
10%
)
2.
Consider
a
CSMA/CD
network
running
at
100Mbps,
over
a
1000m
cable
with
no
repeaters.
The
signal
speed in
the
cable
is
2
×
10
8
m/sec.
What
is
the
minimum
frame
size for check collision reliably?
(
10%
3.
Suppose
two
Ethernet
nodes
of
10Mbps,
A
and
B,
are
attached
to
opposite
ends
of
a
900m cable,
and there are 4 repeaters between A and B. If the
size of frame is 1000 bits,
and the
signal propagation speed is 2
×
10
8
m/s, and each repeater
inserts 20-bit delay.
(15%)
(1) What is the one-way propagation
delay (including repeater delays) between A and
B in second ?
(2) How long
time is node A
’
s a frame
completely delivered at node B?
五、
Consider a LAN
shown below and one class C address 202.1.0.0/24
is available only.
Please accomplish
the following questions: (15%)
(1)
Assign IP
Network number and netmask for all LANs.
(2)
Assign IP
addresses to
all network
interfaces .
(3)
Determine the route table
on router R1.
3
E
2
A
B
1
R1
2
3
1
R2
C
D
HUB
HUB
HUB
F
Answer:
(
1
)网络地址分配
网络
A
、<
/p>
B
、
R1-1
C
、
D
、
R1
-2
R1-3
、
R2-1
E
、
F
、
R2-2
(
2
)端口
IP
地址分配
端口
A
B
R1-1
(
3
)
R1
上的路由表
Dest. Network
三、
Answer follow
questions.(20%)
(
1
)
How
big is the Ethernet address space? The IPv4
address space? (5%)
(
2
)
Compare and contrast link-state
and distance-vector routing algorithm.(5%)
(
3
)
For
a communication session between two hosts, which
host is the client and which
is the
server?(5%)
(
4
)
p>
Consider c
ipher text
“
wklvlvdwhvw
” , and the
Caesar cipher of k=
3 is used. What is
the plain text accordingly? (5%)
4
网络地址
202.1.1.0/26
202.1.1.64/26
202.1.1.128/26
202.1.1.192/26
网络掩码
255.255.255.0
255.255.255.0
255.255.255.0
255.255.255.0
IP
地址
202.1.1.2
202.1.1.1
202.1.1.63
端口
C
D
R1-2
R1-3
IP
地址
202.1.1.65
202.1.1.66
202.1.1.126
202.1.1.190
端口
IP
地址
E
F
202.1.1.193
202.1.1.194
R2-2
202.1.1.254
R2-1
202.1.1.189
next router
N hops
Interface