enthusiasm计算机网络英文题库

2021年1月21日发(作者：檀香炉)
Chapter 3 Transport Layer
1.
A
transport-layer
protocol
provides
for
logical
communication
between
____.

A Application processes

B Hosts

C Routers

D End systems

2. Transport-layer protocols run in ____.

A Servers

B Clients

C Routers

D End systems

3.
In
transport
layer,
the
send
side
breaks
application
messages
into
____,
passes to network layer.

A Frames

B Segments

C Data-grams

D bit streams

4. Services provided by transport layer include ____.

A HTTP and FTP

B TCP and IP

C TCP and UDP

D SMTP

5. Which of the following services is not provided by TCP?

A Delay guarantees and bandwidth guarantees

B Reliable data transfers and flow controls

C Congestion controls

D In-order data transfers

6
.
These
two
minimal
transport-layer
services----____
and
____----are
the
only two services that UDP provides!

A process-to-process data delivery, error checking

B congestion control, reliable data transfer

C flow control, congestion control

D In-order data transfer, error checking

7. Port number’s scop
e is ____ to ____.

A 0, 1023

B 0, 65535

C 0, 127

D 0,255

8
. The port numbers ranging from ____to ____ are called well-known port
number and are restricted.

A 0, 1023

B 0, 65535

C 0, 127

D 0,255

9. UDP socket identified by two components, they are ____.

A source IP addresses and source port numbers

B source IP addresses and destination IP addresses

C destination IP address and destination port numbers

D destination port numbers and source port numbers

10. TCP socket identified by a (an) ____.

A 1-tuple

B 2-tuple

C 3-tuple

D 4-tuple

11. Which of the following applications normally uses UDP services?

A SMTP

B Streaming multimedia

C FTP

D HTTP

12.
Reliable
data
transfer
protocol
over
a
perfectly
reliable

channel
is____.


A




B


C




D



13.
Reliable
data
transfer
protocol
over
a
channel
with
bit

errors
and
packet
losses
is
____.


A



B


C




D



14.
Which
of
the
following
about
reliable
data
transfer
over

a
channel
with
bit
errors
is
not
correct?

A

:
assuming
ACK
and
NAK
will
not
be
corrupted

B

:
assuming
ACK
and
NAK
can
be
corrupted

C

:
only
use
ACK-s

D

:
use
both
ACK-s
and
NAK-s

15.
Which
of
the
following
protocols
is
not
pipelining
proto
cols?


A

TCP
B



C

GO-BACK-N
D

selective
repeat

16.
Which
of
the
following
is
not
correct
about
GBN
protoco
l?

A

Only
using
ACK-s

B

Using
cumulative
ACK-s


C

Receiver
discards
all
out-of-order
packets

D

It
is
not
pipelined
protocol

17.
Which
of
the
following
is
not
correct
about
SR
protocol
?


A

receiver
individually
acknowledges
all
correctly
received
packets

B

sender
only
resends
packets
for
which
ACK
not
received

C

It
limits
sequence
number
of
sent
but
un-ACK-ed
packets


D

It
is
not
a
pipelined
protocol

18. Which of the following about TCP connection is not correct?

A It is a broadcast connection

B It is a point-to- point connection

C It is a pipelined connection

D It is a full duplex connection

19. The SYN segment is used for____.

A TCP connection setup

B TCP flow control

C TCP congestion control

D Closing a TCP connection

20. The FIN segment is used for____.

A TCP connection setup

B TCP flow control

C TCP congestion control

D Closing a TCP connection

does TCP sender perceive congestion?

A Through a timeout event

B Through a receiving duplicate ACK-s event

C Both A and B

D Either A or B

22. Extending host- to-host delivery to process-to-process delivery is
called transport-layer ____ and .

A multiplexing and de-multiplexing

B storing and forwarding

C forwarding and filtering

D switching and routing

23. UDP is a ____ service while TCP is a connection-oriented service.

A Connectionless

B Reliable

C Connection-oriented

D In-order

24. The UDP header has only four fields, they are____.

A Source port number, destination port number, length and checksum

B Source
port
number,
destination
port
number,
source
IP
and
destination
IP

C source IP, destination IP, source MAC address and destination MAC
address

D source IP, destination IP, sequence number and ACK sequence number

25. There are two 16-bit integers: 1110 0110 0110 0110, 1101 0101 0101
0101. Their checksum is____.

A 011

B 100

C 111

D 000


maximum
amount
of
data
that
can
be
grabbed
and
placed
in
a
segment
is limited by the____.

A Maximum segment size (MSS)

B MTU

C Checksum

D Sequence number

27.

The
MSS
is
typically
set
by
first
determining
the
length
of
the
largest
link- layer
frame
that
can
be
sent
by
the
local
sending
host---- the
so-called____.

A Maximum transmission unit (MTU)

B MSS

C Checksum

D Sequence number

28. A File size of 500,000bytes, MSS equals 1000bytes. When we want to
transmit this file with
TCP, the sequence number
of the first
segment is
0, and the sequence number of the second segment is ____.

A 1000

B 999

C 1001

D 500000

29.

Because TCP only acknowledges bytes up to the first missing byte in
the stream, TCP is said to provide____.

A Cumulative acknowledgements

B Selective acknowledgements

C 3 duplicate ACKs

D positive ACKs

30.
Provided
α=,

current
value
of
Estimated-RTT
is
,
Sample-RTT
is
,
then
the new value of Estimated-RTT is ____s.

A

B

C

D

ed
RcvBuffer=20,LastByteRcvd=20,LastByteRead=15,
then
RcvWindow=____.

A 14

B 15

C 16

D 10

32. TCP service does not provide____.

A Reliable data transfer B Flow control

C Delay guarantee
D Congestion control

33. There are two states in TCP congestion control, which are ____.

A slow start and congestion avoidance

B safe start and congestion avoidance

C slow start and congestion abandon

D safe start and congestion abandon

34.
The
transport-layer
protocol
provides
logical
communication
between
____,
and
the
network-layer
protocol
provides
logical
communication
____.

A hosts, processes

B processes, hosts

C threads, processes

D processes, threads

35.
To
implement
the
multicast
services
the
Internet
employs

the
____
protocol.


A

FTP


B

TCP


C

IGMP


D

UDP

36.
If
an
application
developer
chooses
____
protocol,
then
the
application process is almost directly talking with IP.

A HTTP

B RIP

C CSMA/CD

D
UDP

37. ____ maintains connection-state in the end systems. This connection
state
includes
receive
and
send
buffers,
congestion-control
parameters,
and sequence and acknowledgment number parameters.

A UDP
B TCP

C DNS
D HTTP

38.
The
host
that
initiates
the
session
in
the
Internet
is
labeled
as
____.

A server
B user agent
C client


D router

39.
With
TCP
there
is
no
_____
between
sending
and
receiving
transport- layer entities.

A flow control



B handshaking

C. congestion control



D VC setup

40.
The
Internet’s
____
service
helps
prevent
the
Internet
from
e
ntering
a state of gridlock.

A datagram




B congestion control

C sliding window


D timeout event

41. Connection setup at the transport layer involves ____.

A server




B only the two end systems

C client



D router

42.
A
____layer
protocol
provides
for
logical
communication
between
applications.

A transport

B application

C networking

D MAC

43. In static congestion window, if it satisfies W*S/R > RTT + S/R, the
Latency is ____.

A W*S/R
–
( RTT+ S/R)

B 2RTT + O/R

C 2RTT + O/R + (k-1)[W* S/R- (RTT + S/R)]

D 2RTT + S/R

44.
The
receive
side
of
transport
layer
reassembles
segments
into
messages,
passes to ____layer.

A Application

B Networking

C Physical

D MAC

45. In the following four options, which one is correct?

A The variations in the SampleRTT are smoothed out in the computation
of the EstimatedRTT

B
The timeout should be less than the connection’s RTT

C Suppose
that
the
last
SampleRTT
in
a
TCP
connection
is
equal
to
1
sec.
Then the current value of TimeoutInterval will necessarily be≥1 sec

D Suppose
that
the
last
SampleRTT
in
a
TCP
connection
is
equal
to
1
sec.
Then the current value of TimeoutInterval will necessarily be≤1 sec

46. The port number used by HTTP is ____.

A 80

B 25

C 110

D 53

47. The port number used by SMTP is ____.

A 80

B 25

C 110

D 53

48. The port number used by pop3 is ____.

A 80

B 25

C 110

D 53

49. The port number used by DNS is ____.

A 80

B 25

C 110

D 53

50. The port number used by FTP is ____.

A 20 and 21

B 20

C 21

D 53

51. A UDP socket identified by a ____ tuple(s).

A 2

B 4

C 1

D 3

52. A TCP socket identified by a ____ tuple(s).

A 2

B 4

C 1

D 3

53. A TCP socket does not include____.

A Source MAC address

B Source port number

C Destination IP address

D Destination port number

54. Which of following about UDP is not correct.

A It is a reliable data transfer protocol

B It is connectionless

C no handshaking between UDP sender, receiver

D it is a best effort service protocol

55. DNS uses ____ service.

A TCP

B UDP

C Both TCP and UDP

D None of above

56. Which of following about UDP is correct?

A Finer application-level control over what data is sent, and when

B No connection establishment (which can add delay), so no delay for
establish a connection

C No
connection
state
(so,
UDP
can
typically
support
many
active
clients)

D Large packet header overhead (16-B)

57. Streaming media uses a ____ service normally.

A TCP

B UDP

C Both TCP and UDP

D None of above

58. The UDP header has only ____ fields.

A 2

B 4

C 1

D 3

59. Which of the following does not included in UDP header.

A Source port number

B Destination port number

C Checksum

D Sequence number

60. Which of the following is not a pipelining protocol.

A

B Go-Back-N

C Selective repeat

D TCP

61. In the following four descriptions about MSS and MTU, which one is
not correct?

A The
MSS
is
the
maximum
amount
of
application-layer
data
in
the
segment

B The MSS is the maximum size of the TCP segment including headers

C The MSS is typically set by MTU

D The MTU means the largest link-layer frame

62.
The
job
of
gathering
data
chunks,
encapsulating
each
data
chunk
with
header information to create segments and passing the segments to the
network is called ____.

A multiplexing

B de-multiplexing

C forwarding

D routing

63.
In
the
following
four
descriptions
about
the
relationship
between
the
transport layer and the network layer, which one is not correct?

A The transport-layer protocol provides logical communication between
hosts

B The transport-layer protocol provides logical communication between
processes

C The services that a transport-layer protocol can provide are often
constrained by the service model of the network-layer protocol

D A computer network may make available multiple transport protocols

64.
Suppose
the
following
three
8-bit
bytes:
01010101,
01110000,
01001100.
What’s the 1s complement of the sum of these 8
-bit bytes?

A 00010001

B

C 00010010

D

65.
The
following
four
descriptions
about
multiplexing
and
de-multiplexing, which one is correct?

A A
UDP
socket
is
identified
by
a
two-tuples
consisting
of
a
source
port
number and a destination port number.

B If two UDP segment have different source port number, they may be
directed to the same destination process.

C If two TCP segments with different source port number, they may be
directed to the same destination process.

D If two TCP segments with same destination IP address and destination