计算机网络英文试题库附答案chapter3解析Word下载.docx

计算机网络英文试题库附答案chapter3解析Word下载.docx

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DIn-orderdatatransfer,errorchecking

7.Portnumber’sscopeis____to____.

A0,1023

B0,65535

C0,127

D0,255

8.Theportnumbersrangingfrom____to____arecalledwell-knownportnumberandarerestricted.

9.UDPsocketidentifiedbytwocomponents,theyare____.

AsourceIPaddressesandsourceportnumbers

BsourceIPaddressesanddestinationIPaddresses

CdestinationIPaddressanddestinationportnumbers

Ddestinationportnumbersandsourceportnumbers

10.TCPsocketidentifiedbya（an）____.

A1-tuple

B2-tuple

C3-tuple

D4-tuple

11.WhichofthefollowingapplicationsnormallyusesUDPservices?

ASMTP

BStreamingmultimedia

CFTP

DHTTP

12. 

Reliable 

data 

transfer 

protocol 

over 

a 

perfectly 

reliable 

channel 

is____. 

A 

rdt1.0 

B 

rdt2.0 

C 

rdt3.0 

D 

rdt2.1 

13. 

with 

bit 

errors 

and 

packet 

losses 

is 

____. 

14. 

Which 

of 

the 

following 

about 

not 

correct?

RDT2.0:

assuming 

ACK 

NAK 

will 

be 

corrupted 

RDT2.1:

can 

RDT2.2:

only 

use 

ACK-s 

both 

NAK-s 

15. 

protocols 

pipelining 

protocols?

TCP 

GO-BACK-N 

D 

selective 

repeat 

16. 

correct 

GBN 

protocol?

Only 

using 

Using 

cumulative 

Receiver 

discards 

all 

out-of-order 

packets 

It 

pipelined 

17. 

SR 

receiver 

individually 

acknowledges 

correctly 

received 

sender 

resends 

for 

which 

limits 

sequence 

number 

sent 

but 

un-ACK-ed 

protocol

18.WhichofthefollowingaboutTCPconnectionisnotcorrect?

AItisabroadcastconnection

BItisapoint-to-pointconnection

CItisapipelinedconnection

DItisafullduplexconnection

19.TheSYNsegmentisusedfor____.

ATCPconnectionsetup

BTCPflowcontrol

CTCPcongestioncontrol

DClosingaTCPconnection

20.TheFINsegmentisusedfor____.

21.HowdoesTCPsenderperceivecongestion?

AThroughatimeoutevent

BThroughareceivingduplicateACK-sevent

CBothAandB

DEitherAorB

22.Extendinghost-to-hostdeliverytoprocess-to-processdeliveryiscalledtransport-layer____and.

Amultiplexingandde-multiplexing

Bstoringandforwarding

Cforwardingandfiltering

Dswitchingandrouting

23.UDPisa____servicewhileTCPisaconnection-orientedservice.

AConnectionless

BReliable

CConnection-oriented

DIn-order

24.TheUDPheaderhasonlyfourfields,theyare____.

ASourceportnumber,destinationportnumber,lengthandchecksum

BSourceportnumber,destinationportnumber,sourceIPanddestinationIP

CsourceIP,destinationIP,sourceMACaddressanddestinationMACaddress

DsourceIP,destinationIP,sequencenumberandACKsequencenumber

25.Therearetwo16-bitintegers:

1110011001100110,1101010101010101.Theirchecksumis____.

A00011

B11100

C11111

D00000

26.Themaximumamountofdatathatcanbegrabbedandplacedinasegmentislimitedbythe____.

AMaximumsegmentsize（MSS）

BMTU

CChecksum

DSequencenumber

27.TheMSSistypicallysetbyfirstdeterminingthelengthofthelargestlink-layerframethatcanbesentbythelocalsendinghost----theso-called____.

AMaximumtransmissionunit（MTU）

BMSS

28.AFilesizeof500,000bytes,MSSequals1000bytes.WhenwewanttotransmitthisfilewithTCP,thesequencenumberofthefirstsegmentis0,andthesequencenumberofthesecondsegmentis____.

A1000

B999

C1001

D500000

29.BecauseTCPonlyacknowledgesbytesuptothefirstmissingbyteinthestream,TCPissaidtoprovide____.

ACumulativeacknowledgements

BSelectiveacknowledgements

C3duplicateACKs

DpositiveACKs

30.Providedα=0.125,currentvalueofEstimated-RTTis0.4s,Sample-RTTis0.8s,thenthenewvalueofEstimated-RTTis____s.

A0.45

B0.6

C0.7

D0.8

31.ProvidedRcvBuffer=20,LastByteRcvd=20,LastByteRead=15,thenRcvWindow=____.

A14

B15

C16

D10

32.TCPservicedoesnotprovide____.

AReliabledatatransferBFlowcontrol

CDelayguaranteeDCongestioncontrol

33.TherearetwostatesinTCPcongestioncontrol,whichare____.

Aslowstartandcongestionavoidance

Bsafestartandcongestionavoidance

Cslowstartandcongestionabandon

Dsafestartandcongestionabandon

34.Thetransport-layerprotocolprovideslogicalcommunicationbetween____,andthenetwork-layerprotocolprovideslogicalcommunication____.

Ahosts,processes

Bprocesses,hosts

Cthreads,processes

Dprocesses,threads

35. 

To 

implement 

multicast 

services 

Internet 

employs 

____ 

protocol. 

FTP 

TCP 

IGMP 

UDP 

36.Ifanapplicationdeveloperchooses____protocol,thentheapplicationprocessisalmostdirectlytalkingwithIP.

AHTTP

BRIP

CCSMA/CD

DUDP

37.____maintainsconnection-stateintheendsystems.Thisconnectionstateincludesreceiveandsendbuffers,congestion-controlparameters,andsequenceandacknowledgmentnumberparameters.

AUDPBTCPCDNSDHTTP

38.ThehostthatinitiatesthesessionintheInternetislabeledas____.

AserverBuseragentCclientDrouter

39.WithTCPthereisno_____betweensendingandreceivingtransport-layerentities.

AflowcontrolBhandshaking

C.congestioncontrolDVCsetup

40.TheInternet’s____servicehelpspreventtheInternetfromenteringastateofgridlock.

AdatagramBcongestioncontrol

CslidingwindowDtimeoutevent

41.Connectionsetupatthetransportlayerinvolves____.

AserverBonlythetwoendsystems

CclientDrouter

42.A____layerprotocolprovidesforlogicalcommunicationbetweenapplications.

Atransport

Bapplication

Cnetworking

DMAC

43.Instaticcongestionwindow,ifitsatisfiesW*S/R>

RTT+S/R,theLatencyis____.

AW*S/R–（RTT+S/R）

B2RTT+O/R

C2RTT+O/R+（k-1）[W*S/R-（RTT+S/R）]

D2RTT+S/R

44.Thereceivesideoftransportlayerreassemblessegmentsintomessages,passesto____layer.

AApplication

BNetworking

CPhysical

45.Inthefollowingfouroptions,whichoneiscorrect?

AThevariationsintheSampleRTTaresmoothedoutinthecomputationoftheEstimatedRTT

BThetimeoutshouldbelessthantheconnection’sRTT

CSupposethatthelastSampleRTTinaTCPconnectionisequalto1sec.ThenthecurrentvalueofTimeoutIntervalwillnecessarilybe≥1sec

DSupposethatthelastSampleRTTinaTCPconnectionisequalto1sec.ThenthecurrentvalueofTimeoutIntervalwillnecessarilybe≤1sec

46.TheportnumberusedbyHTTPis____.

A80

B25

C110

D53

47.TheportnumberusedbySMTPis____.

48.Theportnumberusedbypop3is____.

49.TheportnumberusedbyDNSis____.

50.TheportnumberusedbyFTPis____.

A20and21

B20

C21

51.AUDPsocketidentifiedbya____tuple（s）.

A2

B4

C1

D3

52.ATCPsocketidentifiedbya____tuple（s）.

53.ATCPsocketdoesnotinclude____.

ASourceMACaddress

BSourceportnumber

CDestinationIPaddress

DDestinationportnumber

54.WhichoffollowingaboutUDPisnotcorrect.

AItisareliabledatatransferprotocol

BItisconnectionless

CnohandshakingbetweenUDPsender,receiver

Ditisabesteffortserviceprotocol

55.DNSuses____service.

ATCP

BUDP

CBothTCPandUDP

DNoneofabove

56.WhichoffollowingaboutUDPiscorrect?

AFinerapplication-levelcontroloverwhatdataissent,andwhen

BNoconnectionestablishment（whichcanadddelay）,sonodelayforestablishaconnection

CNoconnectionstate（so,UDPcantypicallysupportmanyactiveclients）

DLargepacketheaderoverhead（16-B）

57.Streamingmediausesa____servicenormally.

58.TheUDPheaderhasonly____fields.

59.WhichofthefollowingdoesnotincludedinUDPheader.

ASourceportnumber

BDestinationportnumber

60.Whichofthefollowingisnotapipeliningprotocol.

ARdt1.0

BGo-Back-N

CSelectiverepeat

DTCP

61.InthefollowingfourdescriptionsaboutMSSandMTU,whichoneisnotcorrect?

ATheMSSisthemaximumamountofapplication-layerdatainthesegment

BTheMSSisthemaximumsizeoftheTCPsegmentincludingheaders

CTheMSSistypicallysetbyMTU

DTheMTUmeansthe