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2021年1月23日发(作者：巴陵戏)

注意：

1.
可以用
英文
答题，也可以用
中文
答题
。

2.
答案请写在每种类型题目的
答题区中
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一

Multiple Choice(20 points, 2 points each problem)

1
、
OSPF routing protocol typically runs over:
A. IP


B. TCP


C. UDP


D. none of the above
2
、
The transfer of an Web document from one host to another is:
A. loss-intolerant and time insensitive
B. loss- tolerant and time sensitive
C. loss-intolerant and time sensitive
D. none of the above
3
、
Consider sending a 999 byte datagram into a link that has an MTU of 500 bytes.
A. 2 fragments are created with offset field value 0, 500, respectively
B. 3 fragments are created with offset field value 0, 480,960, respectively
C. 3 fragments are created with offset field value 0, 60,120, respectively
D. None of the above
4
、
Suppose an application generates chunks of 120 bytes of data every second, and each chunk gets encapsulated in
a
TCP
segment
and
then
an
IP
datagram(no
options
fields).
What
percentage
of
each
datagram
will
contain
application data?
A. 80%



B. 75%



C. 60%


D. 25%
5
、
We are sending a 30 Mbit MP3 file from a source host to a destination host. Suppose there is only one link
between source and destination and the link has a transmission rate of 10 Mbps. Assume that the propagation speed
is 2 * 108 meters/sec, and the distance between source and destination is 10,000 km. Also suppose that message
switching
is
used,
with
the
message
consisting
of
the
entire
MP3
file.
How
many
bits
will
the
source
have
transmitted when the first bit arrives at the destination?
A. 1 bit


B. 30,000,000 bits

C. 500,000 bits


D. none of the above
6
、
In routing among ASs, which of the following issues dominants
A. Policy







B. geographical distance between ASs
C. current congestion levels in the ASs


D. number of ASs traversed
7
、
An ARP query packet is encapsulated in
A. a link- layer frame addressed to a specific adapter
B. a link-layer broadcast frame

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C. an IP datagram
D. none of the above
8
、
A taking-turns protocol has which of the following characteristics
A. there is no single point failure.
B. it does not generate collisions
C. there is no master node
D. all of the above
9
、
TCP has which of the following characteristics:
A. flow control




B. connection establishment
C. congestion control


D. all of the above
10
、
Which of the following statements is true?
A. A network adapter (NIC) is an autonomous unit.
B. In a distance-vector routing algorithm, each node has a map of the entire network and determines the shortest
path from itself to all other nodes in the network.
C. An adapter’s MAC address has a flat structure and doesn’t
change no matter where the adapter goes.
D. none of the above
二

Fill in the Blanks(24 points, 2 points each problem)

1
、
As a packet travels from one node to the subsequent node along the path, the packet suffers from several types
of delays at each node along the path. The most important of these delays are the _______delay, _______delay,
_________ delay, and _______delay.
2
、
The
Internet
mail
system
has
three
major
components:
_________,
_________________,
and
______________________.
3
、
________ _______________________________ is called transport- layer multiplexing and demultiplexing.
4
、
Computer networks that__________________________ are called virtual- circuit networks; Computer networks
that ___________________ are called datagram networks.
5
、
There are 4 com
ponents in router’s architecture. They are input ports, ________, output ports and _________.
And ______connects the router’s input ports to its output ports; _______ executes the routing protocols.

6
、
Historically, two routing protocols have been used extensively for routing within an autonomous system in the
Internet:
RIP
protocol
and
________
protocol.
And
______
is
a
distance-vector
protocol.
And
_______
is
a
link-state protocol.
7
、
TCP provides a _______service to its applications to eliminate the possibility of the sender overwhelming the
receiver..

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