计算机网络英文题库(附答案)chapter3

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 ____.