傳輸層小測題

1、v1.0可編輯可修改1Quizzes for Tran sport LayerDepartme nt of Computer Scie nee1.One of the main duties of the transportlayer is to provide _com mun icati on.A)no de-to-nodeB)host-to-hostC)process-to-processD)None of the choices are correct2.A clie nt program n ormally uses _port nu mber. A server programno

2、 rmally uses _port nu mber.A)a well-k nown; an ephemeralB)an ephemeral; a well-k nownC)a private; a well-k nownD)None of the choices are correct3.A socket address is a comb in ati on ofA) A MAC address and a logical addressB) A MAC address and a port nu mberC) a user-specific address and a logical a

3、ddressD) None of the choices are correct4._ means accepting items from more than one source. _means deliveri ng items to more tha n one source.A)Demultiplexi ng; Multiplex ingB)Multiplexi ng; Demultiplexi ngC)En capsulati on; Decapsulatio nD)Pulli ng; Pushi ng5._means the producer delivers the items

4、 when they are produced. _v1.0可編輯可修改2A)C)7.In theGo-Back-N protocol, the maximumsend window size isand the8.receive window size isseque nee nu mber.A)B)C)D)1; 1m1; 2,where m is related to the number of bitsmaximumin theIn the selective-repeat protocol, the maximum send window size isandthe maximum r

5、eceive win dow size is,where m is the nu mber of bits in9.the seque nee.A)B)C)D)UDP is a1; 11; 2tran sport protocol.means the con sumer takes the items whe n it is ready to do so.A)Push ing; pull ingB)Pulli ng; push ingC)Forward ing; accept ingD)None of the choices are correct6.In the stop-a nd-wait

6、 protocol, the maximum send window size is _and themaximum receive wi ndow size is _where m is the nu mber of bits in thesequenee.1; 1B)m1; 2D)v1.0可編輯可修改33.A)connectionl ess, reliableB)connection-orie nted, un reliableC)connectionl ess, un reliableD)None of the choices are correctUDP is an

7、 acronym for_.A)User Delivery ProtocolB)User Datagram ProcedureC)User Datagram ProtocolD)None of the choices are correctAt the transport layer, to define the processes, we need two identifierscalledA)logical addressesB)physical addressesC)port addressesD)None of the choices are correctThe ports rang

8、ing from 0 to 1,023 are called the _ports. The portsranging from 1,024 to 49,151 are called _ports. The ports rangingfrom 49,152 to 65,535 are called the _ports.A) well-k nown; registered; dyn amic or privateB) registered; dyn amic or private; well-k nownC) private or dyn amic; well-k nown; register

9、edD) private or dyn amic; registered; well-k nownUDP and TCP are two protocols at the _layer.A) data linkB) n etworkC) tran sportD) applicati onv1.0可編輯可修改414.Which of the following functions are performed by UDPA) process-to-process com mun icati onB) host-to-host com muni cati onC) node-to-node com

10、 municationD) 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 con trolB)connection-orie nted deliveryC)error con trolD)None of the choices are correct17.The source port number on the UDP user datagram header defines _A)the

11、 sending computerB)the receivi ng 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 datagramsv1.0可編輯可修改5B)segme ntsC)fram

12、esD)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-orie ntedB)message-orie ntedC)block-orie ntedD)None of the choices are correct22.TCP groups a number of bytes together into a packet called a _A)user datagramB)segme ntC)da

13、tagramD)None of the choices are correct23.TCP is a(n) _protocol.A)connection-orie ntedB)connectionl essC)both connection-orie nted and conn ecti onl essD)None of the choices are correct24.TCP is a(n) _transport protocol.A)un reliableB)best-effort deliveryC)reliablev1.0可編輯可修改A) first6D)None of the ch

14、oices are correct25.TCP uses _to check the safe and sound arrival of data.A)an ack no wledgme nt mecha nismB)out-of-ba nd sig nali ngC)the services of ano ther protocolD)None of the choices are correct26.The bytes of data being transferredin each connection are numbered by TCP. Thenu mberi ng starts

15、 with a _.A)0B)1C)ran domly gen erated nu mberD)None of the choices are correct27.In TCP, the sequenee number for each segment is the number of the _byte(virtual byte) carried in that segme nt.A)firstB)lastC)middleD)None of the choices are correct28.Communication in TCP is _.A)simplexB)half-duplexC)

16、full-duplexD)None of the choices are correct29.In TCP, the value of the ack no wledgme nt field in a sent segme nt defi nes theseque nee nu mber related to the_byte a party expects to receive n ext.B)lastv1.0可編輯可修改7C)n extD)None of the choices are correct30.The inclusion of the checksum in the TCP s

17、egment is_.A)opti onalB)man datoryC)depe nds on the type of dataD)None of the choices are correct31.In TCP, a SYN segment consumes _sequenee number(s).A)noB)oneC)twoD)None of the choices are correct32.In TCP, a SYN + ACK segment consumes _sequenee numbers.A)noB)threeC)twoD)one33.In TCP, an ACKsegmen

18、t, if carrying no data, consumes_sequenee number(s).A)noB)oneC)twoD)None of the choices are correct34.The connection establishment procedure in TCP is susceptible to a serioussecurity problem called the _attack.A)ACK floodi ngB)FIN floodi ngC)SYN floodi ngv1.0可編輯可修改A) packet8D)None of the choices ar

19、e correct35.The SYNflooding attack belongs to a group of security attacks known as a_attack.A)denial of serviceB)replayC)man-i n-the middleD)None of the choices are correct36.In TCP, a FIN segment consumes _sequenee numbers if it does not carry data.A)twoB)threeC)noD)one37.In TCP, a FIN + ACK segmen

20、t consumes _sequenee number(s) if it does notcarry data.A)twoB)threeC)oneD)no38.In TCP, one end can stop sending data while still receiving data. This is calleda _term in ati on.A)half-closeB)half-ope nC)full-closeD)None of the choices are correct39.TCP sliding windows are _oriented.B)segme ntv1.0可編

21、輯可修改A) sender9however,C)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)mi nimumD)None of the choices are correct41.In TCP, the window should not be_.A)openedB)closedC)shru nkD)slide42.In TCP, the receiver can temporarily shut d

22、own the window; the sender,can always send a segme nt of _byte(s) after the window is shut dow n.A)tenB)zeroC)oneD)None of the choices are correct43.A serious problem can arise in the sliding window operation when either thesending applicati on program creates data slowly or the receivi ng applicati

23、 on program con sumes data slowly, or both. This problem is called the _.A)silly wi ndow syn dromeB)un expected syn dromeC)window bugD)None of the choices are correct44.Nagles algorithm can solve the sillywindow syndrome created by the _v1.0可編輯可修改A) one10B)receiverC)both sen der and receiverD)None o

24、f the choices are correct45.Clarks solution can solve the silly window syndrome created by the _A)senderB)receiverC)both sen der and receiverD)None of the choices are correct46.Delayed ack no wledgme nt can solve the silly win dow syn drome created by theA)senderB)receiverC)both sen der and receiver

25、D)None of the choices are correct47.In TCP, an ACKsegments that carry no data consumes _sequenee number(s).A)noB)oneC)twoD)None of the choices are correct48.In modern implementationsof TCP, a retransmissionoccurs if the retransmissiontimer expires or _duplicate ACK segme nts have arrived.A)oneB)twoC

26、)threeD)None of the choices are correct49.In TCP,_retransmission timer is set for an ACK segment.B)a previousv1.0可編輯可修改11C)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.Weneed to multi

27、ply the header length field by _to find the totalnumberof bytes in the TCP header.A)2B)4C)6D)None of the choices are correct52.In TCP, urge nt data requires the urge nt poin ter field as well as the URG bit(to be set) in the _field.A)con trolB)offsetC)seque nee nu mberD)None of the choices are corre

28、ct53.In TCP, if the ACKvalue 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)retra nsmissi onB)persiste neev1.0可編輯可修改12C)keepaliveD)None of the choices are correct55.In TCP, the

29、 _timer is needed to handle the zero window-size advertisement.A)retra nsmissi onB)persiste neeC)keepaliveD)None of the choices are correct56.In TCP, Karns algorithm is used in calculations by the_timer.A)retra nsmissi onB)persiste neeC)keepaliveD)None of the choices are correct57.In TCP, a special

30、segment called a probe is sent by a sending TCPwhen the _timer goes off.A)tran smissi onB)persiste neeC)keepaliveD)None of the choices are correct58._control refers to the mechanisms and techniques to keep the load belowthe capacity.A)flowB)errorC)con gesti onD)None of the choices are correct59.In T

31、CPs _ algorithm the size of the con gesti onwi ndow in creasesexp onen tially un til it reaches a threshold.A)con gesti on avoida neev1.0可編輯可修改13B)con gesti on detect ionC)slow startD)None of the choices are correct60.In TCPs _algorithm the size of the con gesti on window in creasesadditively un til

32、 con gesti on is detected.A)con gesti on avoida neeB)con gesti on detect ionC)slow startD)None of the choices are correct61._treats the two sig ns of con gesti on detect ions, timeout and threeduplicate ACKs, in the same way.A)Taho TCPB)Re no TCPC)new Re no TCPD)None of the choices are correct62.In

33、_TCP, when the connection is established, TCP starts the slow startalgorithms and sets the ssthresh variable to a pre-agreed value (n ormally 64or 128 kilobytes) and the cwnd variable to 1 MSS.A)Taho TCPB)Re no TCPC)new Re no TCPD)None of the choices are correct63.The _added a new state to the conge

34、stion control FSM, called the fastrecovery state.A)Taho TCPB)Reno TCPC)new Re no TCPv1.0可編輯可修改14D)None of the choices are correct64.The _treated the two signals of congestion, timeout and arrival ofthree duplicate ACKs, differe ntly.A)Taho TCPB)Re no TCPC)new Re no TCPD)None of the choices are corre

35、ct65.The _state in Reno TCP is a state somehow between the slow start andthe con gestio n avoida nee states.A)con gesti on avoida neeB)con gesti on detect ionC)slow recoveryD)None of the choices are correct66.In the Reno TCP, when TCP enters thefast recovery, if duplicateACKs continueto come, TCP _.

36、A)stays in this state, but the cwnd grows additivelyB)stays in this state, but the cwnd grows exp onen tiallyC)moves to slow start stateD)moves to the con gesti on avoida nee state but deflate the size of the cwndto 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 grows exp onen tiallyC)moves to slow start stateD)moves to the con gesti on avoida nee state but deflate the size of the cwnd to ssthresh value68.In the Reno TCP, when TCP enters the fast recove