传输层小测题[综合教育]

1、Quizzes for Transport LayerDepartment of Computer Science1. One of the main duties of the transport layer is to provide _ communication. A) node-to-node B) host-to-host C) process-to-process D) None of the choices are correct 2. A client program normally uses _ port number. A server program normally

2、 uses _ port number. A) a well-known; an ephemeral B) an ephemeral; a well-known C) a private; a well-known D) None of the choices are correct3. A socket address is a combination of _.A) A MAC address and a logical addressB) A MAC address and a port numberC) a user-specific address and a logical add

3、ressD) None of the choices are correct4. _ means accepting items from more than one source. _ means delivering items to more than one source. A) Demultiplexing; Multiplexing B) Multiplexing; Demultiplexing C) Encapsulation; Decapsulation D) Pulling; Pushing5. _ means the producer delivers the items

4、when they are produced. _ means the consumer takes the items when it is ready to do so. A) Pushing; pulling B) Pulling; pushing C) Forwarding; accepting D) None of the choices are correct6. In the stop-and-wait protocol, the maximum send window size is _ and the maximum receive window size is _ wher

5、e m is the number of bits in the sequence. A) 1; 1 B) 2m; 1 C) 1; 2m D) 2m; 2m7. In the Go-Back-N protocol, the maximum send window size is _ and the maximum receive window size is _, where m is related to the number of bits in the sequence number. A) 1; 1 B) 1; 2m C) 2m 1; 1 D) 2m 1; 2m 18. In the

6、selective-repeat protocol, the maximum send window size is _ and the maximum receive window size is _, where m is the number of bits in the sequence. A) 1; 1 B) 1; 2m 1 C) 2m 1; 1 D) 2m 1; 2m 19. UDP is a _ transport protocol. A) connectionless, reliable B) connection-oriented, unreliable C) connect

7、ionless, unreliable D) None of the choices are correct10. UDP is an acronym for _. A) User Delivery Protocol B) User Datagram Procedure C) User Datagram Protocol D) None of the choices are correct11. At the transport layer, to define the processes, we need two identifiers called _. A) logical addres

8、ses B) physical addresses C) port addresses D) None of the choices are correct12. The ports ranging from 0 to 1,023 are called the _ ports. The ports ranging from 1,024 to 49,151 are called _ ports. The ports ranging from 49,152 to 65,535 are called the _ ports. A) well-known; registered; dynamic or

9、 private B) registered; dynamic or private; well-known C) private or dynamic; well-known; registered D) private or dynamic; registered; well-known13. UDP and TCP are two protocols at the _ layer. A) data link B) network C) transport D) application14. Which of the following functions are performed by

10、 UDP? A) process-to-process communication B) host-to-host communication C) node-to-node communication D) None of the choices are correct15. A port number is _ bits long.A)8B)16C)32D)6416. Which of the following does UDP provide?A)flow controlB)connection-oriented deliveryC)error controlD)None of the

11、 choices are correct17. The source port number on the UDP user datagram header defines _.A)the sending computerB)the receiving computerC)the process running on the sending computerD)None of the choices are correct18. To use the services of UDP, we need _ socket addresses.A)fourB)twoC)threeD)None of

12、the choices are correct19. UDP packets are called _ .A)user datagramsB)segmentsC)framesD)None of the choices are correct20. UDP packets have a fixed-size header of _ bytes.A)16B)8C)40D)3221. TCP is a _ protocol.A)byte-orientedB)message-orientedC)block-orientedD)None of the choices are correct22. TCP

13、 groups a number of bytes together into a packet called a _.A)user datagramB)segmentC)datagramD)None of the choices are correct23. TCP is a(n) _ protocol.A)connection-orientedB)connectionlessC)both connection-oriented and connectionlessD)None of the choices are correct24. TCP is a(n) _ transport pro

14、tocol.A)unreliableB)best-effort deliveryC)reliableD)None of the choices are correct25. TCP uses _ to check the safe and sound arrival of data.A)an acknowledgment mechanismB)out-of-band signalingC)the services of another protocolD)None of the choices are correct26. The bytes of data being transferred

15、 in each connection are numbered by TCP. The numbering starts with a _.A)0B)1C)randomly generated numberD)None of the choices are correct27. In TCP, the sequence number for each segment is the number of the _ byte (virtual byte) carried in that segment.A)firstB)lastC)middleD)None of the choices are

16、correct28. Communication in TCP is _.A)simplexB)half-duplexC)full-duplexD)None of the choices are correct29. In TCP, the value of the acknowledgment field in a sent segment defines the sequence number related to the _ byte a party expects to receive next.A)firstB)lastC)nextD)None of the choices are

17、correct30. The inclusion of the checksum in the TCP segment is _.A)optionalB)mandatoryC)depends on the type of dataD)None of the choices are correct31. In TCP, a SYN segment consumes _ sequence number(s).A)noB)oneC)twoD)None of the choices are correct32. In TCP, a SYN + ACK segment consumes _ sequen

18、ce numbers.A)noB)threeC)twoD)one33. In TCP, an ACK segment, if carrying no data, consumes _ sequence number(s).A)noB)oneC)twoD)None of the choices are correct34. The connection establishment procedure in TCP is susceptible to a serious security problem called the _ attack.A)ACK floodingB)FIN floodin

19、gC)SYN floodingD)None of the choices are correct35. The SYN flooding attack belongs to a group of security attacks known as a _ attack.A)denial of serviceB)replayC)man-in-the middleD)None of the choices are correct36. In TCP, a FIN segment consumes _ sequence numbers if it does not carry data.A)twoB

20、)threeC)noD)one37. In TCP, a FIN + ACK segment consumes _ sequence number(s) if it does not carry data.A)twoB)threeC)oneD)no38. In TCP, one end can stop sending data while still receiving data. This is called a _ termination.A)half-closeB)half-openC)full-closeD)None of the choices are correct39. TCP

21、 sliding windows are _ oriented.A)packetB)segmentC)byteD)None of the choices are correct40. In TCP, the size of the send window is the _ of rwnd and cwnd.A)maximumB)sum ofC)minimumD)None of the choices are correct41. In TCP, the window should not be _.A)openedB)closedC)shrunkD)slide42. In TCP, the r

22、eceiver can temporarily shut down the window; the sender, however, can always send a segment of _ byte(s) after the window is shut down.A)tenB)zeroC)oneD)None of the choices are correct43. A serious problem can arise in the sliding window operation when either the sending application program creates

23、 data slowly or the receiving application program consumes data slowly, or both. This problem is called the _.A)silly window syndromeB)unexpected syndromeC)window bugD)None of the choices are correct44. Nagles algorithm can solve the silly window syndrome created by the _.A)senderB)receiverC)both se

24、nder and receiverD)None of the choices are correct45. Clarks solution can solve the silly window syndrome created by the _.A)senderB)receiverC)both sender and receiverD)None of the choices are correct46. Delayed acknowledgment can solve the silly window syndrome created by the _.A)senderB)receiverC)

25、both sender and receiverD)None of the choices are correct47. In TCP, an ACK segments that carry no data consumes _ sequence number(s).A)noB)oneC)twoD)None of the choices are correct48. In modern implementations of TCP, a retransmission occurs if the retransmission timer expires or _ duplicate ACK se

26、gments have arrived.A)oneB)twoC)threeD)None of the choices are correct49. In TCP, _ retransmission timer is set for an ACK segment.A)oneB)a previousC)noD)None of the choices are correct50. In TCP, there can be _ RTT measurement(s) in progress at any time.A)twoB)only oneC)severalD)None of the choices

27、 are correct51. We need to multiply the header length field by _ to find the total number of bytes in the TCP header.A)2B)4C)6D)None of the choices are correct52. In TCP, urgent data requires the urgent pointer field as well as the URG bit (to be set) in the _ field.A)controlB)offsetC)sequence numbe

28、rD)None of the choices are correct53. In TCP, if the ACK value is 200, then byte _ has been received successfully.A)199B)200C)201D)None of the choices are correct54. In TCP, the _ timer prevents a long idle connection between two TCPs.A)retransmissionB)persistenceC)keepaliveD)None of the choices are

29、 correct55. In TCP, the _ timer is needed to handle the zero window-size advertisement.A)retransmissionB)persistenceC)keepaliveD)None of the choices are correct56. In TCP, Karns algorithm is used in calculations by the _ timer.A)retransmissionB)persistenceC)keepaliveD)None of the choices are correct

30、57. In TCP, a special segment called a probe is sent by a sending TCP when the _ timer goes off.A)transmissionB)persistenceC)keepaliveD)None of the choices are correct58. _ control refers to the mechanisms and techniques to keep the load below the capacity.A)flowB)errorC)congestionD)None of the choi

31、ces are correct59. In TCPs _ algorithm the size of the congestion window increases exponentially until it reaches a threshold.A)congestion avoidanceB)congestion detectionC)slow startD)None of the choices are correct60. In TCPs _ algorithm the size of the congestion window increases additively until

32、congestion is detected.A)congestion avoidanceB)congestion detectionC)slow startD)None of the choices are correct61. _ treats the two signs of congestion detections, timeout and three duplicate ACKs, in the same way.A)Taho TCPB)Reno TCPC)new Reno TCPD)None of the choices are correct62. In _ TCP, when

33、 the connection is established, TCP starts the slow start algorithms and sets the ssthresh variable to a pre-agreed value (normally 64 or 128 kilobytes) and the cwnd variable to 1 MSS.A)Taho TCPB)Reno TCPC)new Reno TCPD)None of the choices are correct63. The _ added a new state to the congestion con

34、trol FSM, called the fast recovery state.A)Taho TCPB)Reno TCPC)new Reno TCPD)None of the choices are correct64. The _ treated the two signals of congestion, timeout and arrival of three duplicate ACKs, differently.A)Taho TCPB)Reno TCPC)new Reno TCPD)None of the choices are correct65. The _ state in

35、Reno TCP is a state somehow between the slow start and the congestion avoidance states.A)congestion avoidanceB)congestion detectionC)slow recoveryD)None of the choices are correct66. In the Reno TCP, when TCP enters the fast recovery, if duplicate ACKs continue to come, TCP _.A)stays in this state,

36、but the cwnd grows additivelyB)stays in this state, but the cwnd grows exponentiallyC)moves to slow start stateD)moves to the congestion avoidance state but deflate the size of the cwnd to ssthresh value67. In the Reno TCP, when TCP enters the fast recovery, if a timeout occurs, TCP _.A)stays in thi

37、s state, but the cwnd grows additivelyB)stays in this state, but the cwnd grows exponentiallyC)moves to slow start stateD)moves to the congestion avoidance state but deflate the size of the cwnd to ssthresh value68. In the Reno TCP, when TCP enters the fast recovery, if a new (non duplicate) ACK arrives T