发布时间 : 星期四 文章计算机网络英文题库(附答案)chapter3(推荐文档)更新完毕开始阅读
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 entering 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 Rdt1.0 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 11101101 C 00010010 D 10001000
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 port number, they must be the same TCP connection. 66. UDP and TCP both have the fields except ____. A source port number B destination port number
C checksum D receive window
67. If we define N to be the window size, base to be the sequence number of the oldest unacknowledged packet, and next-seq-num to be the smallest unused sequence number, then the interval [nextseqnum,base+N-1] corresponds to packet that ____. A can be sent immediately
B have already been transmitted and acknowledged C cannot be used
D have been sent but not yet acknowledged
68. Which of the following about TCP is not correct? A It is a connectionless protocol