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1、Quizzes for Transport Layer Department of Computer Science 1.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 uses
2、_ 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 correct 3.A socket address is a combination of _.A)A MAC address and a logical address B)A MAC address and a port number C)a user-specific address and a logical address D)None of
3、the choices are correct 4._ 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;Pushing 5._ means the producer delivers the items when they are produced._
4、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 correct 6.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 se
5、quence.A)1;1 B)2m;1 C)1;2m D)2m;2m 7.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 1 8.In the selective-repeat protocol,the maximum send window size
6、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 1 9.UDP is a _ transport protocol.A)connectionless,reliable B)connection-oriented,unreliable C)connectionless,unreliable D)None of the choices are correct 10.UDP is an acrony
7、m for _.A)User Delivery Protocol B)User Datagram Procedure C)User Datagram Protocol D)None of the choices are correct 11.At the transport layer,to define the processes,we need two identifiers called _.A)logical addresses B)physical addresses C)port addresses D)None of the choices are correct 12.The
8、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 private B)registered;dynamic or private;well-known C)private or dynamic;well-known;register
9、ed D)private or dynamic;registered;well-known 13.UDP and TCP are two protocols at the _ layer.A)data link B)network C)transport D)application 14.Which of the following functions are performed by UDP A)process-to-process communication B)host-to-host communication C)node-to-node communication D)None o
10、f the choices are correct 15.A port number is _ bits long.A)8 B)16 C)32 D)64 16.Which of the following does UDP provide A)flow control B)connection-oriented delivery C)error control D)None of the choices are correct 17.The source port number on the UDP user datagram header defines _.A)the sending co
11、mputer B)the receiving computer C)the process running on the sending computer D)None of the choices are correct 18.To use the services of UDP,we need _ socket addresses.A)four B)two C)three D)None of the choices are correct 19.UDP packets are called _.A)user datagrams B)segments C)frames D)None of t
12、he choices are correct 20.UDP packets have a fixed-size header of _ bytes.A)16 B)8 C)40 D)32 21.TCP is a _ protocol.A)byte-oriented B)message-oriented C)block-oriented D)None of the choices are correct 22.TCP groups a number of bytes together into a packet called a _.A)user datagram B)segment C)data
13、gram D)None of the choices are correct 23.TCP is a(n)_ protocol.A)connection-oriented B)connectionless C)both connection-oriented and connectionless D)None of the choices are correct 24.TCP is a(n)_ transport protocol.A)unreliable B)best-effort delivery C)reliable D)None of the choices are correct 2
14、5.TCP uses _ to check the safe and sound arrival of data.A)an acknowledgment mechanism B)out-of-band signaling C)the services of another protocol D)None of the choices are correct 26.The bytes of data being transferred in each connection are numbered by TCP.The numbering starts with a _.A)0 B)1 C)ra
15、ndomly generated number D)None of the choices are correct 27.In TCP,the sequence number for each segment is the number of the _ byte(virtual byte)carried in that segment.A)first B)last C)middle D)None of the choices are correct 28.Communication in TCP is _.A)simplex B)half-duplex C)full-duplex D)Non
16、e of the choices are correct 29.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)first B)last C)next D)None of the choices are correct 30.The inclusion of the checksum in the TCP segment is _.A)optional
17、 B)mandatory C)depends on the type of data D)None of the choices are correct 31.In TCP,a SYN segment consumes _ sequence number(s).A)no B)one C)two D)None of the choices are correct 32.In TCP,a SYN+ACK segment consumes _ sequence numbers.A)no B)three C)two D)one 33.In TCP,an ACK segment,if carrying
18、no data,consumes _ sequence number(s).A)no B)one C)two D)None of the choices are correct 34.The connection establishment procedure in TCP is susceptible to a serious security problem called the _ attack.A)ACK flooding B)FIN flooding C)SYN flooding D)None of the choices are correct 35.The SYN floodin
19、g attack belongs to a group of security attacks known as a _ attack.A)denial of service B)replay C)man-in-the middle D)None of the choices are correct 36.In TCP,a FIN segment consumes _ sequence numbers if it does not carry data.A)two B)three C)no D)one 37.In TCP,a FIN+ACK segment consumes _ sequenc
20、e number(s)if it does not carry data.A)two B)three C)one D)no 38.In TCP,one end can stop sending data while still receiving data.This is called a _ termination.A)half-close B)half-open C)full-close D)None of the choices are correct 39.TCP sliding windows are _ oriented.A)packet B)segment C)byte D)No
21、ne of the choices are correct 40.In TCP,the size of the send window is the _ of rwnd and cwnd.A)maximum B)sum of C)minimum D)None of the choices are correct 41.In TCP,the window should not be _.A)opened B)closed C)shrunk D)slide 42.In TCP,the receiver can temporarily shut down the window;the sender,
22、however,can always send a segment of _ byte(s)after the window is shut down.A)ten B)zero C)one D)None of the choices are correct 43.A serious problem can arise in the sliding window operation when either the sending application program creates data slowly or the receiving application program consume
23、s data slowly,or both.This problem is called the _.A)silly window syndrome B)unexpected syndrome C)window bug D)None of the choices are correct 44.Nagles algorithm can solve the silly window syndrome created by the _.A)sender B)receiver C)both sender and receiver D)None of the choices are correct 45
24、.Clarks solution can solve the silly window syndrome created by the _.A)sender B)receiver C)both sender and receiver D)None of the choices are correct 46.Delayed acknowledgment can solve the silly window syndrome created by the _.A)sender B)receiver C)both sender and receiver D)None of the choices a
25、re correct 47.In TCP,an ACK segments that carry no data consumes _ sequence number(s).A)no B)one C)two D)None of the choices are correct 48.In modern implementations of TCP,a retransmission occurs if the retransmission timer expires or _ duplicate ACK segments have arrived.A)one B)two C)three D)None
26、 of the choices are correct 49.In TCP,_ retransmission timer is set for an ACK segment.A)one B)a previous C)no D)None of the choices are correct 50.In TCP,there can be _ RTT measurement(s)in progress at any time.A)two B)only one C)several D)None of the choices are correct 51.We need to multiply the
27、header length field by _ to find the total number of bytes in the TCP header.A)2 B)4 C)6 D)None of the choices are correct 52.In TCP,urgent data requires the urgent pointer field as well as the URG bit(to be set)in the _ field.A)control B)offset C)sequence number D)None of the choices are correct 53
28、.In TCP,if the ACK value is 200,then byte _ has been received successfully.A)199 B)200 C)201 D)None of the choices are correct 54.In TCP,the _ timer prevents a long idle connection between two TCPs.A)retransmission B)persistence C)keepalive D)None of the choices are correct 55.In TCP,the _ timer is
29、needed to handle the zero window-size advertisement.A)retransmission B)persistence C)keepalive D)None of the choices are correct 56.In TCP,Karns algorithm is used in calculations by the _ timer.A)retransmission B)persistence C)keepalive D)None of the choices are correct 57.In TCP,a special segment c
30、alled a probe is sent by a sending TCP when the _ timer goes off.A)transmission B)persistence C)keepalive D)None of the choices are correct 58._ control refers to the mechanisms and techniques to keep the load below the capacity.A)flow B)error C)congestion D)None of the choices are correct 59.In TCP
31、s _ algorithm the size of the congestion window increases exponentially until it reaches a threshold.A)congestion avoidance B)congestion detection C)slow start D)None of the choices are correct 60.In TCPs _ algorithm the size of the congestion window increases additively until congestion is detected
32、.A)congestion avoidance B)congestion detection C)slow start D)None of the choices are correct 61._ treats the two signs of congestion detections,timeout and three duplicate ACKs,in the same way.A)Taho TCP B)Reno TCP C)new Reno TCP D)None of the choices are correct 62.In _ TCP,when the connection is
33、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 TCP B)Reno TCP C)new Reno TCP D)None of the choices are correct 63.The _ added a new state to the congestion control FSM,called the
34、 fast recovery state.A)Taho TCP B)Reno TCP C)new Reno TCP D)None of the choices are correct 64.The _ treated the two signals of congestion,timeout and arrival of three duplicate ACKs,differently.A)Taho TCP B)Reno TCP C)new Reno TCP D)None of the choices are correct 65.The _ state in Reno TCP is a st
35、ate somehow between the slow start and the congestion avoidance states.A)congestion avoidance B)congestion detection C)slow recovery D)None of the choices are correct 66.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 grow
36、s additively B)stays in this state,but the cwnd grows exponentially C)moves to slow start state D)moves to the congestion avoidance state but deflate the size of the cwnd to ssthresh value 67.In the Reno TCP,when TCP enters the fast recovery,if a timeout occurs,TCP _.A)stays in this state,but the cw
37、nd grows additively B)stays in this state,but the cwnd grows exponentially C)moves to slow start state D)moves to the congestion avoidance state but deflate the size of the cwnd to ssthresh value 68.In the Reno TCP,when TCP enters the fast recovery,if a new(non duplicate)ACK arrives TCP _.A)stays in
38、 this state,but the cwnd grows additively B)stays in this state,but the cwnd grows exponentially C)moves to slow start state D)moves to the congestion avoidance state but deflate the size of the cwnd to ssthresh value 69.A later version of TCP,called _ TCP,made an extra optimization on the _ TCP.A)N
39、ew Reno;Reno B)New Taho;Taho C)New Reno;Taho D)New Taho;Reno 70.In the slow start algorithm,the size of the congestion window grows _ until _.A)exponentially;it reaches a threshold B)exponentially;congestion is detected C)additively;it reaches a threshold D)additively;congestion is detected 71.In th
40、e congestion avoidance algorithm,the size of the congestion window grows _ congestion is detected.A)exponentially;it reaches a threshold B)exponentially;congestion is detected C)additively;it reaches a threshold D)additively;congestion is detected 72.The congestion window size,after it passes the initial slow start state,follows a saw tooth pattern called _.A)exponential increase,additive decrease B)additive increase,exponential decrease C)multiplicative increase,additive decrease D)additive increase,multiplicative decrease