计算机网络教程自顶向下方法选择题及答案Chapt3TransportLayer-QUIZZ

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Chapter3TransportLayer

1.

Oneofthemaindutiesofthetransportlayeristoprovide____________communication.

A) node-to-node

B) host-to-host

C) process-to-process

D) Noneofthechoicesarecorrect

2.

Aclientprogramnormallyuses____________portnumber.Aserverprogramnormallyuses__________portnumber.

A) awell-known;anephemeral

B) anephemeral;awell-known

C) aprivate;awell-known

D) Noneofthechoicesarecorrect

3.

Asocketaddressisacombinationof__________.

A) AMACaddressandalogicaladdress

B) AMACaddressandaportnumber

C) auser-specificaddressandalogicaladdress

D) Noneofthechoicesarecorrect

4.

______________meansacceptingitemsfrommorethanonesource.______________meansdeliveringitemstomorethanonesource.

A) Demultiplexing;Multiplexing

B) Multiplexing;Demultiplexing

C) Encapsulation;Decapsulation

D) Pulling;Pushing

5.

________meanstheproducerdeliverstheitemswhentheyareproduced._______meanstheconsumertakestheitemswhenitisreadytodoso.

A) Pushing;pulling

B) Pulling;pushing

C) Forwarding;accepting

D) Noneofthechoicesarecorrect

6.

Inthestop-and-waitprotocol,themaximumsendwindowsizeis______andthemaximumreceivewindowsizeis_______wheremisthenumberofbitsinthesequence.

A) 1;1

B) 2m;–1

C) 1;2m

D) 2m;2m

7.

IntheGo-Back-Nprotocol,themaximumsendwindowsizeis______andthemaximumreceivewindowsizeis_______,wheremisrelatedtothenumberofbitsinthesequence.number.

A) 1;1

B) 1;2m

C) 2m–1;1

D) 2m–1;2m–1

8.

Intheselective-repeatprotocol,themaximumsendwindowsizeis______andthemaximumreceivewindowsizeis_______,wheremisthenumberofbitsinthesequence.

A) 1;1

B) 1;2m–1

C) 2m–1;1

D) 2m–1;2m–1

9.

UDPisa________________transportprotocol.

A) connectionless,reliable

B) connection-oriented,unreliable

C) connectionless,unreliable

D) Noneofthechoicesarecorrect

10.

UDPisanacronymfor_______.

A) UserDeliveryProtocol

B) UserDatagramProcedure

C) UserDatagramProtocol

D) Noneofthechoicesarecorrect

11.

Atthetransportlayer,todefinetheprocesses,weneedtwoidentifierscalled____________.

A) logicaladdresses

B) physicaladdresses

C) portaddresses

D) Noneofthechoicesarecorrect

12.

Theportsrangingfrom0to1,023arecalledthe___________ports.Theportsrangingfrom1,024to49,151arecalled___________ports.Theportsrangingfrom49,152to65,535arecalledthe___________ports.

A) well-known;registered;dynamicorprivate

B) registered;dynamicorprivate;well-known

C) privateordynamic;well-known;registered

D) privateordynamic;registered;well-known

13.

UDPandTCParetwoprotocolsatthe___________layer.

A) datalink

B) network

C) transport

D) application

14.

WhichofthefollowingfunctionsareperformedbyUDP?

A) process-to-processcommunication

B) host-to-hostcommunication

C) node-to-nodecommunication

D) Noneofthechoicesarecorrect

15.

Aportnumberis_______bitslong.

A) 8

B) 16

C) 32

D) 64

16.

WhichofthefollowingdoesUDPprovide?

A) flowcontrol

B) connection-orienteddelivery

C) errorcontrol

D) Noneofthechoicesarecorrect

17.

ThesourceportnumberontheUDPuserdatagramheaderdefines_______.

A) thesendingcomputer

B) thereceivingcomputer

C) theprocessrunningonthesendingcomputer

D) Noneofthechoicesarecorrect

18.

TousetheservicesofUDP,weneed________socketaddresses.

A) four

B) two

C) three

D) Noneofthechoicesarecorrect

19.

UDPpacketsarecalled__________.

A) userdatagrams

B) segments

C) frames

D) Noneofthechoicesarecorrect

20.

UDPpacketshaveafixed-sizeheaderof_______bytes.

A) 16

B) 8

C) 40

D) 32

21.

TCPisa__________protocol.

A) byte-oriented

B) message-oriented

C) block-oriented

D) Noneofthechoicesarecorrect

22.

TCPgroupsanumberofbytestogetherintoapacketcalleda___________.

A) userdatagram

B) segment

C) datagram

D) Noneofthechoicesarecorrect

23.

TCPisa(n)___________protocol.

A) connection-oriented

B) connectionless

C) bothconnection-orientedandconnectionless

D) Noneofthechoicesarecorrect

24.

TCPisa(n)_______transportprotocol.

A) unreliable

B) best-effortdelivery

C) reliable

D) Noneofthechoicesarecorrect

25.

TCPuses_________________tocheckthesafeandsoundarrivalofdata.

A) anacknowledgmentmechanism

B) out-of-bandsignaling

C) theservicesofanotherprotocol

D) Noneofthechoicesarecorrect

26.

ThebytesofdatabeingtransferredineachconnectionarenumberedbyTCP.Thenumberingstartswitha__________________.

A) 0

B) 1

C) randomlygeneratednumber

D) Noneofthechoicesarecorrect

27.

InTCP,thesequencenumberforeachsegmentisthenumberofthe_______byte(virtualbyte)carriedinthatsegment.

A) first

B) last

C) middle

D) Noneofthechoicesarecorrect

28.

CommunicationinTCPis___________.

A) simplex

B) half-duplex

C) full-duplex

D) Noneofthechoicesarecorrect

29.

InTCP,thevalueoftheacknowledgmentfieldinasentsegmentdefinesthesequencenumberrelatedtothe______byteapartyexpectstoreceivenext.

A) first

B) last

C) next

D) Noneofthechoicesarecorrect

30.

TheinclusionofthechecksumintheTCPsegmentis________.

A) optional

B) mandatory

C) dependsonthetypeofdata

D) Noneofthechoicesarecorrect

31.

InTCP,aSYNsegmentconsumes_____sequencenumber(s).

A) no

B) one

C) two

D) Noneofthechoicesarecorrect

32.

InTCP,aSYN+ACKsegmentconsumes_____sequencenumbers.

A) no

B) three

C) two

D) one

33.

InTCP,anACKsegment,ifcarryingnodata,consumes______sequencenumber(s).

A) no

B) one

C) two

D) Noneofthechoicesarecorrect

34.

TheconnectionestablishmentprocedureinTCPissusceptibletoaserioussecurityproblemcalledthe_________attack.

A) ACKflooding

B) FINflooding

C) SYNflooding

D) Noneofthechoicesarecorrect

35.

TheSYNfloodingattackbelongstoagroupofsecurityattacksknownasa_____attack.

A) denialofservice

B) replay

C) man-in-themiddle

D) Noneofthechoicesarecorrect

36.

InTCP,aFINsegmentconsumes____sequencenumbersifitdoesnotcarrydata.

A) two

B) three

C) no

D) one

37.

InTCP,aFIN+ACKsegmentconsumes_____sequencenumber(s)ifitdoesnotcarrydata.

A) two

B) three

C) one

D) no

38.

InTCP,oneendcanstopsendingdatawhilestillreceivingdata.Thisiscalleda______termination.

A) half-close

B) half-open

C) full-close

D) Noneofthechoicesarecorrect

39.

TCPslidingwindowsare__________oriented.

A) packet

B) segment

C) byte

D) Noneofthechoicesarecorrect

40.

InTCP,thesizeofthesendwindowisthe________ofrwndandcwnd.

A) maximum

B) sumof

C) minimum

D) Noneofthechoicesarecorrect

41.

InTCP,thewindowshouldnotbe_________.

A) opened

B) closed

C) shrunk

D) slide

42.

InTCP,thereceivercantemporarilyshutdownthewindow;thesender,however,canalwayssendasegmentof_____byte(s)afterthewindowisshutdown.

A) ten

B) zero

C) one

D) Noneofthechoicesarecorrect

43.

Aseriousproblemcanariseintheslidingwindowoperationwheneitherthesendingapplicationprogramcreatesdataslowlyorthereceivingapplicationprogramconsumesdataslowly,orboth.Thisproblemiscalledthe______.

A) sillywindowsyndrome

B) unexpectedsyndrome

C) windowbug

D) Noneofthechoicesarecorrect

44.

Nagle'salgorithmcansolvethesillywindowsyndromecreatedbythe_________.

A) sender

B) receiver

C) bothsenderandreceiver

D) Noneofthechoicesarecorrect

45.

Clark'ssolutioncansolvethesillywindowsyndromecreatedbythe_________.

A) sender

B) receiver

C) bothsenderandreceiver

D) Noneofthechoicesarecorrect

46.

Delayedacknowledgmentcansolvethesillywindowsyndromecreatedbythe_________.

A) sender

B) receiver

C) bothsenderandreceiver

D) Noneofthechoicesarecorrect

47.

InTCP,anACKsegmentsthatcarrynodataconsumes_______sequencenumber(s).

A) no

B) one

C) two

D) Noneofthechoicesarecorrect

48.

InmodernimplementationsofTCP,aretransmissionoccursiftheretransmissiontimerexpiresor________duplicateACKsegmentshavearrived.

A) one

B) two

C) three

D) Noneofthechoicesarecorrect

49.

InTCP,________retransmissiontimerissetforanACKsegment.

A) one

B) aprevious

C) no

D) Noneofthechoicesarecorrect

50.

InTCP,therecanbe______RTTmeasurement(s)inprogressatanytime.

A) two

B) onlyone

C) several

D) Noneofthechoicesarecorrect

51.

Weneedtomultiplytheheaderlengthfieldby_______tofindthetotalnumberofbytesintheTCPheader.

A) 2

B) 4

C) 6

D) Noneofthechoicesarecorrect

52.

InTCP,urgentdatarequirestheurgentpointerfieldaswellastheURGbit(tobeset)inthe_______field.

A) control

B) offset

C) sequencenumber

D) Noneofthechoicesarecorrect

53.

InTCP,iftheACKvalueis200,thenbyte_______hasbeenreceivedsuccessfully.

A) 199

B) 200

C) 201

D) Noneofthechoicesarecorrect

54.

InTCP,the_______timerpreventsalongidleconnectionbetweentwoTCPs.

A) retransmission

B) persistence

C) keepalive

D) Noneofthechoicesarecorrect

55.

InTCP,the_______timerisneededtohandlethezerowindow-sizeadvertisement.

A) retransmission

B) persistence

C) keepalive

D) Noneofthechoicesarecorrect

56.

InTCP,Karn'salgorithmisusedincalculationsbythe_______timer.

A) retransmission

B) persistence

C) keepalive

D) Noneofthechoicesarecorrect

57.

InTCP,aspecialsegmentcalledaprobeissentbyasendingTCPwhenthe_______timergoesoff.

A) transmission

B) persistence

C) keepalive

D) Noneofthechoicesarecorrect

58.

__________controlreferstothemechanismsandtechniquestokeeptheloadbelowthecapacity.

A) flow

B) error

C) congestion

D) Noneofthechoicesarecorrect

59.

InTCP's________algorithmthesizeofthecongestionwindowincreasesexponentiallyuntilitreachesathreshold.

A) congestionavoidance

B) congestiondetection

C) slowstart

D) Noneofthechoicesarecorrect

60.

InTCP's__________algorithmthesizeofthecongestionwindowincreasesadditivelyuntilcongestionisdetected.

A) congestionavoidance

B) congestiondetection

C) slowstart

D) Noneofthechoicesarecorrect

61.

________treatsthetwosignsofcongestiondetections,timeoutandthreeduplicateACKs,inthesameway.

A) TahoTCP

B) RenoTCP

C) newRenoTCP

D) Noneofthechoicesarecorrect

62.

In______TCP,whentheconnectionisestablished,TCPstartstheslowstartalgorithmsandsetsthessthreshvariabletoapre-agreedvalue(normally64or128kilobytes)andthecwndvariableto1MSS.

A) TahoTCP

B) RenoTCP

C) newRenoTCP

D) Noneofthechoicesarecorrect

63.

The___________addedanewstatetothecongestioncontrolFSM,calledthefastrecoverystate.

A) TahoTCP

B) RenoTCP

C) newRenoTCP

D) Noneofthechoicesarecorrect

64.

The___________treatedthetwosignalsofcongestion,timeoutandarrivalofthreeduplicateACKs,differently.

A) TahoTCP

B) RenoTCP

C) newRenoTCP

D) Noneofthechoicesarecorrect

65.

The__________stateinRenoTCPisastatesomehowbetweentheslowstartandthecongestionavoidancestates.

A) congestionavoidance

B) congestiondetection

C) slowrecovery

D) Noneofthechoicesarecorrect

66.

IntheRenoTCP,whenTCPentersthefastrecovery,ifduplicateACKscontinuetocome,TCP____________________________________.

A) staysinthisstate,butthecwndgrowsadditively

B) staysinthisstate,butthecwndgrowsexponentially

C) movestoslowstartstate

D) movestothecongestionavoidancestatebutdeflatethesizeofthecwndtossthreshvalue

67.

IntheRenoTCP,whenTCPentersthefastrecovery,ifatimeoutoccurs,TCP____________________________________.

A) staysinthisstate,butthecwndgrowsadditively

B) staysinthisstate,butthecwndgrowsexponentially

C) movestoslowstartstate

D) movestothecongestionavoidancestatebutdeflatethesizeofthecwndtossthreshvalue

68.

IntheRenoTCP,whenTCPentersthefastrecovery,ifanew(nonduplicate)ACKarrivesTCP____________________________________.

A) staysinthisstate,b