传输层小测题

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1、除即可-传输层小测题（总10页）-本页仅作为文档封面，使用 一-内页可以根据需求调整合iQuizzes for Transport LayerDepartment of Computer Science1. One of the main duties of the transport layer is to providecommunication.A) no de-t o-nodeB) host-to-hostC) process-to-processD) None of the choices are correct2. A client program normally usespor

2、t number. A server program normallyusesport number.A) a well-known; an ephemeralB) an ephemeral; a well-knownC) a private; a well-knownD) 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

3、address and a logical addressD) None of the choices are correct4. means accepting items from more than one source.meansdelivering items to more than one source.A) Demultiplex!ng; Multiplex!ngB) Multiplexing; DemultiplexingC) Encapsulation; DecapsulationD) Pulling; Pushing5. means the producer delive

4、rs the items when they are produced.meansthe consumer takes the items when it is ready to do so.A) Pushing; pullingB) Pulling; pushingC) Forwarding; acceptingD) None of the choices arecorrect6. In the stop-a ndwait protocol, the maximum send window size is and themaximum receive window size iswhere

5、m is the number of bits in the sequenee.A) 1;1B) 2; -1C) 1; 2D) 2; 2ra7. In the Go-Back-N protocol, the maximum send window size isand the maximumreceive window size is, where m is related to the number of bits in the sequencenumber.A) 1；1B) 1; 2C) 2m_1;1D) 2-1;2_18. In the selective-repeat protocol

6、, the maximum send window size is and themaximum receive window size iswhere m is the number of bits in the sequence.A) 1；1B) 1; 2C) 2m1; 1D) 2”, 2m_19. UDP is atransport protocol.A) connection less, reliableB) connection-onented? unreliableC)connect! on less, unreliableD)None of the choices are cor

7、rect10. UDP is an acronym for.A) User Delivery ProtocolB) User Datagram ProcedureC) User Datagram ProtocolD) None of the choices are correct11. At the transport layer, to define the processes, we need two identifiers calledA) logical addressesB) physical addressesC) port addressesD) None of the choi

8、ces are correct12. The ports ranging from 0 to 1,023 are called theports. The ports rangingfrom 1,024 to 49,151 are calledports. The ports ranging from 49152 to65,535 are called theports.A) well-known; registered; dynamic or privateB) registered; dynamic or private; well-kmownC) private or dynamic;

9、well-known; registeredD) private or dynamic; registered; well-known13. UDP and TCP are two protocols at thelayer.A) data linkB) networkC) transportD) application14. Which of the following functions are performed by UDPA) process-to-process communicationB) host-to-host communicationC) node-to-node co

10、mmunicationD) None of the choices are correct15. A port number isbits long.A) 8B) 16C) 32D) 6416. Which of the following does UDP provideA) flow controlB) connection-oriented deliveryC) error controlD) None of the choices arecorrect17. The source port number on the UDP user datagram header definesA)

11、 the sending computerB) the receiving computerC) the process running on the sending computerD) None of the choices arecorrect18. To use the services of UDP, we needsocket addresses.A) fourB) twoC) threeD) None of the choices arecorrect19. UDP packets are called.A) user datagramsB) segmentsC) framesD

12、) None of thechoices are correct20. UDP packets have a fixed-size header ofbytes.A) 16B) 8C) 40D) 3221. TCP is aprotocol.A) byte-orie ntedB) message-orientedC) block-one ntedD) None of the choices are correct22. TCP groups a number of bytes together into a packet called a _A) user datagramB) segment

13、C) datagramD) None of the choices are correct23. TCP is a(n)protocol.A) connection-one ntedB) conn ectionlessC) both connection-oriented and connectionlessD) None of the choices are correct24. TCP is a(n)transport protocol.A) unr eliableB) best-effortdeliveryC) reliableD) None of thechoices are corr

14、ect25. TCP usesto check the safe and sound arrival of data.A) an ack no wledgment mecha nismB) out-of-band signalingC) the services of another protocolD) None of the choices are correct26. The bytes of data being transferred in each connection are numbered by TCP. The numbering starts with a.A) 0B)

15、1C) randomly generated numberD) None of the choices are correct27. In TCP, the sequenee number for each segment is the number of thebyte(virtual byte) carried in that segment.A) firstB) lastC) middleD) None of the choices are correct28. Communication in TCP is.A) simplexB) half-duplexC) full-duplexD

16、) None of the choices are correct29 In TCP, the value of the acknowledgment field in a sent segment defines the sequenee number related to thebyte a party expects to receive next.A) firstB) lastC) nextD) None of thechoices are correct30. The inclusion of the checksum in the TCP segment is.A) optiona

17、lB) man datoryC) depends onthe typeof dataD) Noneof thechoices are correct31. In TCP, a SYN segment consumessequenee number(s).A) noB) oneC) twoD) Noneof thechoices are correct32. In TCP, a SYN + ACK segment consumessequence numbers.A) noB) threeC) twoD) one33. In TCP, an ACK segment, if carrying no

18、 data, consumessequenee number(s).A) noB) oneC) twoD) None of the choices are correct34. The connection establishment procedure in TCP is susceptible to a serious securityproblem called theattackA) ACK floodingB) FIN floodingC) SYN floodingD) None of the choicesarecorrect35. The SYN flooding attack

19、belongs to a group of security attacks known as aattackA) denial of serviceB) replayC) man-in-the middleD) None of the choicesarecorrect36. In TCP, a FIN segment consumessequenee numbers if it does not carry data.A) twoB) threeC) noD) one37. In TCP, a FIN + ACK segment consumessequence number(s) if

20、it does not carrydata.A) twoB) threeC) oneD) no38 In TCP, one end can stop sen ding data while still receiving data. This is called aterminatio n.A) half-closeB) half-ope nC) full-closeD) None of the choices are correct39. TCP sliding windows areoriented.A) packetB) segme ntC) byteD) None of the cho

21、icesare correct40. In TCP, the size of the send window is theof rwnd and cwnd.A) maximumB) sum ofC) minimumD) None of the choicesare correct41. In TCP, the window should not be.A) openedB) closedC) shru nkD) slide42. In TCP, the receiver can temporarily shut down the window; the sender, however, can

22、always send a segment ofbyte(s) after the window is shut down.A) tenB) zeroC) oneD) None of the choices are correct43. A serious problem can arise in the slidi ng window operati on when either the sen dingapplication program creates data slowly or the receiving application program consumes data slow

23、ly, 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 sender and receiverD) None of the choices are correct45. Clarks sol

24、ution can solve the silly window syndrome created by the.A) sende rB) 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) both sender and receiverD) None of thechoices are correct47.

25、 In TCP, an ACK segments that carry no data consumessequenee 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 orduplicate ACK segments have arrived.A) oneB) twoC) threeD) Noneof the choices a

26、re correct49 In TCP,retransmission timer is set for an ACK segment.A) oneB) a previousC) noD) None of thechoicesarecorrect50. In TCP, there can beRTF measurement(s) in progress at any time.A) twoB) only oneC) severalD) None of thechoicesarecorrect51. We need to multiply the header length field byto

27、find the total number of bytesin 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) inthefield.A) controlB)offsetC)sequenee numberD)None of the choices are correct53. In TCP, if the ACK value is 20

28、0, then bytehas been received successfully.A)199B)200C)201D)None of the choices are correct54. In TCP, thetimer prevents a long idle connection between two TCPs.A)retransmissio nB)persistenceC)keepaliveD)None of the choices are correct55. In TCP, thetimer is needed to handle the zero window-size adv

29、ertisement.A)retra nsmissio nB)persiste neeC)keepaliveD)None of the choices are correct56. In TCP, Karns algorithm is used in calculations by thetimer.A)retransmissio nB)persiste neeC)keepaliveD)None of the choices are correct57. In TCP, a special segment called a probe is sent by a sending TCP when

30、 the timer goes off.5859.60.A) tran smissionB) persiste neeC) keepaliveD) None of the choices are correctcontrol refers to the mechanisms and techniques to keep the load below the capacity.A) flowB) errorC) con gesti onD) Noneof the choices are correctIn TCPsalgorithm the size of the congestion wind

31、ow increases exponentiallyuntil it reaches a threshold.A) congestionavoidaneeB) congestiondetectionC) slow startD) None of the choices are correctIn TCPsalgorithm the size of the con gestion window in creases additivelyuntil congestion is detected.A) congest!onavoidanceB) congestiondetectionC) slow

32、startD) None of the choices are correcttreats the two signs of congestion detections, timeout and three duplicateACKs, in the same way.A) Taho TCPB) Reno TCPC) new Reno TCPD) None of the choices are correct62. InTCP, whe n the conn ection is established, TCP starts the slow start algorithmsand sets

33、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 thechoices are correct63. The added a new state to the congestion control FSM, called the fastrecovery state.A) Taho TCPB) Reno TCPC) new Reno TCP

34、D) None of thechoices are correct64. Thetreated the two signals of congestion, timeout and arrival of threeduplicate ACKs, differently.A) Taho TCPB) Reno TCPC) new Reno TCPD) None of thechoices are correct65. Thestate in Reno TCP is a state somehow between the slow start and thecongest!on avoidance

35、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, but the cwnd grows additivelyB) stays in this state, but the cwnd grows expone

36、ntiallyC) moves to slow start stateD) moves to the congestion avoidanee state but deflate the size ofthe cwnd to ssthresh value67. In the Reno TCP, when TCP enters the fast recovery, if a timeout occurs, TCPA) stays in this state, but the cwnd grows additivelyB) stays in this state, but the cwnd gro

37、ws exponentiallyC) moves to slow start stateD) moves to the congest!on avoidanee state but deflate the size ofthe cwnd to ssthresh value68 In the Reno TCP, when TCP enters the fast recovery, if a new (non duplicate) ACK arrives TCP.A) stays in this state, but the cwnd grows additivelyB) stays in thi

38、s state, but the cwnd grows exponentiallyC) moves to slow start stateD) moves to the congest!on avoidanee state but deflate the size ofthe cwnd to ssthresh value69. A later version of TCP, calledTCP, made an extra optimization on theTCP.A) New Reno; RenoB) New Taho; TahoC) New Reno; TahoD) New Taho;

39、 Reno70. In the slow start algorithm, the size of the congestion window growsuntilA) exponendaily; it reaches a thresholdB) exponentially; congestion is detectedC) additively; it reaches a thresholdD) additively: congestion is detected71. In the congestion avoidance algorithm, the size of the conges

40、t!on window grows congestion is detected.A) exponentially; it reaches a thresholdB) exponendaily; congestion is detectedC) additively: it reaches a thresholdD) additively: congestion is detected72. The congestion window size, after it passes the initial slow start state, follows a sawtooth pattern called.A) exponential in crease, additive decreaseB) additive in crease, exp onen tial decreaseC) multiplicative increase, additive decreaseD) additive in crease, multiplicative decrease