复习题chapter3.docx
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复习题chapter3
Chapter3TransportLayer
1.Atransport-layerprotocolprovidesforlogicalcommunicationbetween____.
AApplicationprocesses
BHosts
CRouters
DEndsystems
2.Transport-layerprotocolsrunin____.
AServers
BClients
CRouters
DEndsystems
3.Intransportlayer,thesendsidebreaksapplicationmessagesinto____,passestonetworklayer.
AFrames
BSegments
CData-grams
Dbitstreams
4.Servicesprovidedbytransportlayerinclude____.
AHTTPandFTP
BTCPandIP
CTCPandUDP
DSMTP
5.WhichofthefollowingservicesisnotprovidedbyTCP?
ADelayguaranteesandbandwidthguarantees
BReliabledatatransfersandflowcontrols
CCongestioncontrols
DIn-orderdatatransfers
6.Thesetwominimaltransport-layerservices----____and____----aretheonlytwoservicesthatUDPprovides!
Aprocess-to-processdatadelivery,errorchecking
Bcongestioncontrol,reliabledatatransfer
Cflowcontrol,congestioncontrol
DIn-orderdatatransfer,errorchecking
7.Portnumber’sscopeis____to____.
A0,1023
B0,65535
C0,127
D0,255
8.Theportnumbersrangingfrom____to____arecalledwell-knownportnumberandarerestricted有一定限制的.
A0,1023
B0,65535
C0,127
D0,255
9.UDPsocketidentifiedbytwocomponents,theyare____.
AsourceIPaddressesandsourceportnumbers
BsourceIPaddressesanddestinationIPaddresses
CdestinationIPaddressanddestinationportnumbers
Ddestinationportnumbersandsourceportnumbers
10.TCPsocketidentifiedbya（an）____.
A1-tuple
B2-tuple
C3-tuple
D4-tuple元组
11.WhichofthefollowingapplicationsnormallyusesUDPservices?
ASMTP
BStreamingmultimedia
CFTP
DHTTP
18.WhichofthefollowingaboutTCPconnectionisnotcorrect?
AItisabroadcastconnection
BItisapoint-to-pointconnection
CItisapipelinedconnection
DItisafullduplexconnection
19.TheSYNsegmentisusedfor____.
ATCPconnectionsetup
BTCPflowcontrol
CTCPcongestioncontrol
DClosingaTCPconnection
20.TheFINsegmentisusedfor____.
ATCPconnectionsetup
BTCPflowcontrol
CTCPcongestioncontrol
DClosingaTCPconnection
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
26.Themaximumamountofdatathatcanbegrabbedandplacedinasegmentislimitedbythe____.
AMaximumsegmentsize（MSS）
BMTU
CChecksum
DSequencenumber
27.TheMSSistypicallysetbyfirstdeterminingthelengthofthelargestlink-layerframethatcanbesentbythelocalsendinghost----theso-called____.
AMaximumtransmissionunit（MTU）
BMSS
CChecksum
DSequencenumber
29.BecauseTCPonlyacknowledgesbytesuptothefirstmissingbyteinthestream,TCPissaidtoprovide____.
ACumulativeacknowledgements
BSelectiveacknowledgements
C3duplicateACKs
DpositiveACKs
32.TCPservicedoesnotprovide____.
AReliabledatatransferBFlowcontrol
CDelayguaranteeDCongestioncontrol
33.TherearetwostatesinTCPcongestioncontrol,whichare____.
Aslowstartandcongestionavoidance
Bsafestartandcongestionavoidance
Cslowstartandcongestionabandon
Dsafestartandcongestionabandon
34.Thetransport-layerprotocolprovideslogicalcommunicationbetween____,andthenetwork-layerprotocolprovideslogicalcommunication____.
Ahosts,processes
Bprocesses,hosts
Cthreads,processes
Dprocesses,threads
37.____maintainsconnection-stateintheendsystems.Thisconnectionstateincludesreceiveandsendbuffers,congestion-controlparameters,andsequenceandacknowledgmentnumberparameters.
AUDPBTCPCDNSDHTTP
39.WithTCPthereisno_____betweensendingandreceivingtransport-layerentities.
AflowcontrolBhandshaking
C.congestioncontrolDVCsetup
40.TheInternet’s____servicehelpspreventtheInternetfromenteringastateofgridlock.
AdatagramBcongestioncontrol
CslidingwindowDtimeoutevent
41.Connectionsetupatthetransportlayerinvolves____.
AserverBonlythetwoendsystems
CclientDrouter
42.A____layerprotocolprovidesforlogicalcommunicationbetweenapplications.
Atransport
Bapplication
Cnetworking
DMAC
44.Thereceivesideoftransportlayerreassemblessegmentsintomessages,passesto____layer.
AApplication
BNetworking
CPhysical
DMAC
46.TheportnumberusedbyHTTPis____.
A80
B25
C110
D53
47.TheportnumberusedbySMTPis____.
A80
B25
C110
D53
48.Theportnumberusedbypop3is____.
A80
B25
C110
D53
49.TheportnumberusedbyDNSis____.
A80
B25
C110
D53
50.TheportnumberusedbyFTPis____.
A20and21
B20
C21
D53
51.AUDPsocketidentifiedbya____tuple（s）.
A2
B4
C1
D3
52.ATCPsocketidentifiedbya____tuple（s）.
A2
B4
C1
D3
53.ATCPsocketdoesnotinclude____.
ASourceMACaddress
BSourceportnumber
CDestinationIPaddress
DDestinationportnumber
54.WhichoffollowingaboutUDPisnotcorrect.
AItisareliabledatatransferprotocol
BItisconnectionless
CnohandshakingbetweenUDPsender,receiver
Ditisabesteffortserviceprotocol
55.DNSuses____service.
ATCP
BUDP
CBothTCPandUDP
DNoneofabove
57.Streamingmediausesa____servicenormally.
ATCP
BUDP
CBothTCPandUDP
DNoneofabove
58.TheUDPheaderhasonly____fields.
A2
B4
C1
D3
59.WhichofthefollowingdoesnotincludedinUDPheader.
ASourceportnumber
BDestinationportnumber
CChecksum
DSequencenumber
DAcomputernetworkmaymakeavailablemultipletransportprotocols
66.UDPandTCPbothhavethefieldsexcept____.
Asourceportnumber
Bdestinationportnumber
Cchecksum
Dreceivewindow
68.WhichofthefollowingaboutTCPisnotcorrect?
AItisaconnectionlessprotocol
BPoint-to-pointprotocol
CReliable,in-orderbytesteamprotocol
DPipelinedprotocol
69.WhichofthefollowingaboutTCPisnotcorrect?
AItisaconnectionlessprotocol
Bfullduplexdatatransferprotocol
Cconnection-orientedprotocol
Dflowcontrolledprotocol
70.Themaximumamountofdatathatcanbegrabbedandplacedinasegmentislimitedbythe____.
AMaximumsegmentsize（MSS）
BMTU
CSequencenumber
DChecksum
71.TheMSSistypicallysetbyfirstdeterminingthelengthofthelargestlink-layerframethatcanbesentbythelocalsendinghost（theso-called____）,andthenwillfitintoasinglelink-layerframe.
AMaximumsegmentsize（MSS）
BMTU
CSequencenumber
DChecksum
73.Whichofthefollowingfieldisnotusedforconnectionsetupandteardown?
ASequencenumber
BTST
CSYN
DFIN
74.____isthebytestreamnumberoffirstbyteinthesegment.
ASequencenumber
BACKnumber
CChecksum
Dportnumber
76.BecauseTCPonlyacknowledgesbytesuptothefirstmissingbyteinthestream,TCPissaidtoprovide____acknowledgements.
ACumulative
BSelective
CSingle
DNegative
77.Fastretransmitmeansinthecasethat____duplicateACK-sarereceived,theTCPsenderresendsegmentbeforetimerexpires.
A3
B4
C5
D6
78.TCP____meanssenderwon’toverflowreceiver’sbufferbytransmittingtoomuch,toofast.
AFlowcontrol
BCongestioncontrol
CReliabledatatransfer
DConnection-orientedservice
79.TCPprovidesflowcontrolbyhavingthesendermaintainavariablecalledthe____.
AReceivewindow
BCongestionwindow
CSlidingwindow
Dbuffer
80.HowdoesTCPsenderperceivecongestion?
ATimeout
B3duplicateACK-s
CBothAandB
DNoneofabove
81.Transportprotocolsrunin____.
AServers
BClients
CRouters
DEndsystems
82.WhichofthefollowingservicesisnotprovidedbyTCP?
ADelayguaranteesandbandwidthguarantees
BReliabledatatransfersandflowcontrols
CCongestioncontrols
DIn-orderdatatransfers
83.WhichservicedoesUDPnotprovide?
Amultiplexing
Bde-multiplexing
Cerror-detection
Berror-correction
85.WhichofthefollowingapplicationsnormallyusesUDPservices?
ASMTP
BStreamingmultimedia
CFTP
DHTTP
87.TheSYNsegmentisusedfor____.
ATCPconnectionsetup
BTCPflowcontrol
CTCPcongestioncontrol
DClosingaTCPconnection
88.Whichservicehelpspreventtheinternetfromenteringastateofgridlock?
Areliabledatatransfer
Bflowcontrol
Ccongestioncontrol
Dhandshakingprocedure
90.Inthefollowingapplications,whichoneisabandwidth-sensitiveapplication?
AE-mail
Bwebapplication
Creal-timeaudio
Dfiletransfer
91.Inthefollowingapplications,whichoneusesUDP?
AE-mail
Bwebapplication
Cfiletransfer
DDNS
93.____isaspeeding-matchingservice---matchingtheratewhichthesenderissendingagainsttherateatwhichthereceivingapplicationisreading.
Acongestioncontrol
Bflowcontrol
Csliding-windowcontrol
Dvariablecontrol
95.Thereare6flagfields.Whichoneistoindicatethatthereceivershouldpassthe
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