发布时间 : 星期日 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29a7c5dcf56527d3240c844769eae009581ba2a4
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 scope 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 rdt1.0 B rdt2.0 C rdt3.0 D rdt2.1
13. Reliable data transfer protocol over a channel with bit errors and packet losses is ____.
A rdt1.0 B rdt2.0 C rdt3.0 D rdt2.1
14. Which of the following about reliable data transfer over a channel with bit errors is not correct?
A RDT2.0: assuming ACK and NAK will not be corrupted B RDT2.1: assuming ACK and NAK can be corrupted C RDT2.2: only use ACK-s
D RDT2.2: use both ACK-s and NAK-s
15. Which of the following protocols is not pipelining protocols? A TCP B rdt3.0
C GO-BACK-N D selective repeat
16. Which of the following is not correct about GBN protocol? 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
21. How 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 0100010001000011 B 1011101110111100 C 1111111111111111 D 1000000000000000
26. The 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=0.125, current value of Estimated-RTT is 0.4s, Sample-RTT is 0.8s, then the new value of Estimated-RTT is ____s. A 0.45 B 0.6 C 0.7 D 0.8
31. Provided 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