传输层小测题

Quizzes for Transport LayerDepartment of Computer Science1.One ofthemaindutiesofthetransportlayeristoprovide_communication.A) node-to-nodeB) host-to-hostC) process-to-processD) None of the choices are correct2. A client program normally uses _ port number. A server program normally uses _ port 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 address and a logical addressD) None of the choices are correct4._ means acceptingitems from more than one source._means delivering items to more than one source.A) Demultiplexing; MultiplexingB) Multiplexing; DemultiplexingC) Encapsulation; DecapsulationD) Pulling; Pushing5._ means the producerdeliversthe itemswhen theyare produced._means the consumer takes the items when it is ready to do so.A) Pushing; pullingB) Pulling; pushingC) Forwarding; acceptingD) 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 _ where m is the number of bits in the sequence.A) 1; 1B) 2m; 1C) 1; 2 mD) 2m; 2 m7.In the Go-Back-N protocol,the maximumsend window size is _ and the maximumreceivewindow sizeis _,where m isrelatedto the number of bitsin thesequence number.A) 1; 1B) 1; 2 mC) 2m 1 ; 1D) 2m 1 ; 2 m 18. In the 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; 1B)m 11; 2C)2m 1 ; 1D)2m 1 ; 2 m 19.UDP is a _ transport protocol.A)connectionless, reliableB)connection-oriented, unreliableC)connectionless, unreliableD)None of the choices are correct10. UDP is an acronym for _.A)User Delivery ProtocolB)User Datagram ProcedureC)User Datagram ProtocolD)None of the choices are correct11.At thetransport layer, to define the processes, we need two identifierscalled_.A) logical addressesB) physical addressesC) port addressesD) 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 privateB) registered; dynamic or private; well-knownC) private or dynamic; well-known; registeredD) private or dynamic; registered; well-known13. UDP and TCP are two protocols at the _ layer.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 communicationD) None of the choices are correct15. A port number is _ bits long.A) 8B) 16C) 32D) 6416. Which of the following does UDP provideA) flow controlB) connection-oriented deliveryC) error controlD) None of the 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 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 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 protocol.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 bytesof data being transferredin each connectionare numbered by TCP. Thenumbering 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 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 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 _ sequence numbers.A) noB) threeC) twoD) one33.In TCP, an ACKsegment, ifcarryingno 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 floodingC) SYN floodingD) None of the choices are correct35.The SYN floodingattackbelongstoa group ofsecurityattacksknown 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 ifitdoes not carrydata.A) twoB) 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 sendingdata whilestillreceivingdata.Thisa _ termination.iscalledA) half-closeB) half-openC) full-closeD) None of the choices are correct39. TCP 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 receiver 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 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 sillyA) senderB) receiverC) both sender and receiverD) None of the choices are correct45.Clarkssolutioncan solvethe sillyA) senderB) receiverC) both sender and receiverD) None of the choices are correctwindow syndrome createdby the _.window syndrome createdby the _.46. Delayed acknowledgment can solve the silly window syndrome created by the_.A) senderB) receiverC) both sender and receiverD) None of the choices are correct47.In TCP, an ACK segments thatcarryno data consumes _ sequence number(s).A) noB) oneC) twoD) None of the choices are correct48.In modern implementationsof TCP, a retransmissionoccursifthe retransmissiontimer expires or _ duplicate ACK segments 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 are correct51.We need to multiplythe header lengthfieldby _ to findthe totalnumberof 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 numberD) None of the choices are correct53.In TCP, ifthe ACKvalue is 200, then byte _ has been receivedsuccessfully.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 correct55.In TCP, the _ timeris needed to handle the zero window-sizeadvertisement.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 correct57.In TCP, a specialsegment calleda probe is sent by a sending TCPwhen the _timer goes off.A) transmissionB) persistenceC) keepaliveD) None of the choices are correct58._ controlrefersto the mechanisms and techniquesto keep the load belowthe capacity.A) flowB) errorC) congestionD) None of the choices 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 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 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 stateto the congestioncontrolFSM, calledthe fastrecovery 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 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 thefastrecovery, if duplicateACKs continueto come, TCP _.A) stays in this 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 value67. In the Reno TCP, when TCP enters the fast recovery, if a timeout occurs, TCP_.A) stays in this 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 TCP _.A) stays in this 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 value69. A later version of TCP, called _ TCP, made an extra optimization on the_ TCP.A) New Reno; RenoB) New Taho; TahoC) New Reno; TahoD) New Taho; Reno70.Intheslowstartalgorithm,thesizeofthecongestionwindowgrows_ until _.A) exponentially; it reaches a thresholdB) exponentially; congestion is detectedC) additively; it reaches a thresholdD) additively; congestion is detected71.In the congestionavoidancealgorithm,the sizeof the congestion_ congestion is detected.A)exponentially; it reaches a thresholdB)exponentially; congestion is detectedC)additively; it reaches a thresholdD)additively; congestion is detected72.The congestionwindow size,afteritpasses the initialslow starta saw tooth pattern called _.A) exponential increase, additive decreaseB) additive increase, exponential decreaseC) multiplicative increase, additive decreaseD) additive increase, multiplicative decreasewindow growsstate,follows