计算机网络英文题库附答案chapter.docx

计算机网络英文题库附答案chapter.docx

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计算机网络英文题库附答案chapter

Chapter1ComputerNetworksandtheInternet

1．The（）isaworldwidecomputernetwork,thatis,anetworkthatinterconnectsmillionsofcomputingdevicesthroughouttheworld.ppt3

ApublicInternet

BIntranet

Cswitchnet

Dtelevisionnet

2．Whichkindofmediaisnotaguidedmedia?

（）

Atwisted-paircopperwire

Bacoaxialcable

Cfiberoptics

Ddigitalsatellitechannel

3．Whichkindofmediaisaguidedmedia?

（）

Ageostationarysatellite

Blow-altitudesatellite

Cfiberoptics

DwirelessLAN

4．Theunitsofdataexchangedbyalink-layerprotocolarecalled（）.

AFrames

BSegments

CDatagrams

Dbitstreams

5．Whichofthefollowingoptionbelongstothecircuit-switchednetworks?

（）

AFDM

BTDM

CVCnetworks

DbothAandB

6．（）makessurethatneithersideofaconnectionoverwhelmstheothersidebysendingtoomanypacketstoofast.

AReliabledatatransfer

BFlowcontrol

CCongestioncontrol

DHandshakingprocedure

7．（）meansthattheswitchmustreceivetheentirepacketbeforeitcanbegintotransmitthefirstbitofthepacketontotheoutboundlink.

AStore-and-forwardtransmission

BFDM

CEnd-to-endconnection

DTDM

8．Datagramnetworksandvirtual-circuitnetworksdifferinthat（）.

Adatagramnetworksarecircuit-switchednetworks,andvirtual-circuitnetworksarepacket-switchednetworks.

Bdatagramnetworksarepacket-switchednetworks,andvirtual-circuitnetworksarecircuit-switchednetworks.

Cdatagramnetworksusedestinationaddressesandvirtual-circuitnetworksuseVC.numberstoforwardpacketstowardtheirdestination.

DdatagramnetworksuseVC.numbersandvirtual-circuitnetworksusedestinationaddressestoforwardpacketstowardtheirdestination.

9．Inthefollowingoptions,whichoneisnotaguidedmedia?

（）

Atwisted-pairwire

Bfiberoptics

Ccoaxialcable

Dsatellite

10．Processingdelaydoesnotincludethetimeto（）.

Aexaminethepacket’sheader

Bwaittotransmitthepacketontothelink

Cdeterminewheretodirectthepacket

Dcheckbit-errorinthepacket

11．Inthefollowingfourdescriptions,whichoneiscorrect?

（）

AThetrafficintensitymustbegreaterthan1.

BThefractionoflostpacketsincreasesasthetrafficintensitydecreases.

CIfthetrafficintensityisclosetozero,theaveragequeuingdelaywillbeclosetozero.

DIfthetrafficintensityisclosetoone,theaveragequeuingdelaywillbeclosetoone.

12．TheInternet’snetworklayerisresponsibleformovingnetwork-layerpacketsknownas（）fromonehosttoanother.

Aframe

Bdatagram

Csegment

Dmessage

13．Theprotocolsofvariouslayersarecalled（）.

Atheprotocolstack

BTCP/IP

CISP

Dnetworkprotocol

14．Therearetwoclassesofpacket-switchednetworks:

（）networksandvirtual-circuitnetworks.

Adatagram

Bcircuit-switched

Ctelevision

Dtelephone

15．Accessnetworkscanbelooselyclassifiedintothreecategories:

residentialaccess,companyaccessand（）access.

Acabled

Bwireless

Ccampus

Dcityarea

Question16～17

Suppose,aistheaveragerateatwhichpacketsarriveatthequeue,Risthetransmissionrate,andallpacketsconsistofLbits,thenthetrafficintensityis（16）,anditshouldnogreaterthan（17）.

16．ALR／a

BLa／R

CRa／L

DLR／a

17．A2

B1

C0

D-1

18．IntheInternet,theequivalentconcepttoendsystemsis（）.

Ahosts

Bservers

Cclients

Drouters

19．IntheInternet,endsystemsareconnectedtogetherby（）.

Acopperwire

Bcoaxialcable

Ccommunicationlinks

Dfiberoptics

20．EndsystemsaccesstotheInternetthroughits（）.

Amodems

Bprotocols

CISP

Dsockets

21．Endsystems,packetswitches,andotherpiecesoftheInternet,run（）thatcontrolthesendingandreceivingofinformationwithintheInternet.

Aprograms

Bprocesses

Capplications

Dprotocols

22．Therearemanyprivatenetworks,suchasmanycorporateandgovernmentnetworks,whosehostscannotexchangemessageswithhostsoutsideoftheprivatenetwork.Theseprivatenetworksareoftenreferredtoas（）.

Ainternets

BLAN

Cintranets

DWAN

23．Theinternetallows（）runningonitsendsystemstoexchangedatawitheachother.

Aclientsapplications

Bserverapplications

CP2Papplications

Ddistributedapplications

24．TheInternetprovidestwoservicestoitsdistributedapplications:

aconnectionlessunreliableserviceand（）service.

Aflowcontrol

Bconnection-orientedreliable

Ccongestioncontrol

DTCP

25．Itdefinestheformatandtheorderofmessagesexchangedbetweentwoormorecommunicatingentities,aswellastheactionstakenonthetransmissionand/orreceiptofamessageorotherevent.Thesentencedescribes（）.

AInternet

Bprotocol

Cintranet

Dnetwork

26．Inthefollowingoptions,whichdoesnotdefineinprotocol?

（）

Atheformatofmessagesexchangedbetweentwoormorecommunicatingentities

Btheorderofmessagesexchangedbetweentwoormorecommunicatingentities

Ctheactionstakenonthetransmissionofamessageorotherevent

Dthetransmissionsignalsaredigitalsignalsoranalogsignals

27．Inthefollowingoptions,whichisdefinedinprotocol?

（）

Atheactionstakenonthetransmissionand/orreceiptofamessageorotherevent

Btheobjectsexchangedbetweencommunicatingentities

Cthecontentintheexchangedmessages

Dthelocationofthehosts

28．Inthefollowingoptions,whichdoesnotbelongtothenetworkedge?

（）

Aendsystems

Brouters

Cclients

Dservers

29．Inthefollowingoptions,whichbelongstothenetworkcore?

（）

Aendsystems

Brouters

Cclients

Dservers

30．Inthefollowingoptions,whichisnotthebundledwiththeInternet’sconnection-orientedservice?

（）

Areliabledatatransfer

Bguaranteeofthetransmissiontime

Cflowcontrol

Dcongestion-control

31．Anapplicationcanrelyontheconnectiontodeliverallofitsdatawithouterrorandintheproperorder.Thesentencedescribes（）.

Aflowcontrol

Bcongestion-control

Creliabledatatransfer

Dconnection-orientedservice

32．Itmakessurethatneithersideofaconnectionoverwhelmstheothersidebysendingtoomanypacketstoofast.Thesentencedescribes（）.

Aflowcontrol

Bcongestion-control

Cconnection-orientedservice

Dreliabledatatransfer

33．IthelpspreventtheInternetfromenteringastateofgridlock.Whenapacketswitchbecomescongested,itsbufferscanoverflowandpacketlosscanoccur.Thesentencedescribes（）.

Aflowcontrol

Bcongestion-control

Cconnection-orientedservice

Dreliabledatatransfer

34．TheInternet’sconnection-orientedservicehasaname,itis（）.

ATCP

BUDP

CTCP/IP

DIP

35．Inthefollowingoptions,whichservicedoesnotbeprovidedtoanapplicationbyTCP?

（）

Areliabletransport

Bflowcontrol

Cvideoconferencing

Dcongestioncontrol

36．TheInternet’sconnectionlessserviceiscalled（）.

ATCP

BUDP

CTCP/IP

DIP

37．Inthefollowingoptions,whichdoesnotuseTCP?

（）

ASMTP

Binternettelephone

CFTP

DHTTP

38．Inthefollowingoptions,whichdoesnotuseUDP?

（）

AInternetphone

Bvideoconferencing

Cstreamingmultimedia

Dtelnet

39．Therearetwofundamentalapproachestobuildinganetworkcore,（）andpacketswitching.

Aelectricalcurrentswitching

Bcircuitswitching

Cdataswitching

Dmessageswitching

40．In（）networks,theresourcesneededalongapathtoprovideforcommunicationbetweentheendsystemarereservedforthedurationofthecommunicationsession.

Apacket-switched

Bdata-switched

Ccircuit-switched

Dmessage-switched

41．In（）networks,theresourcesarenotreserved;asession’smessagesusetheresourcesondemand,andasaconsequence,mayhavetowaitforaccesstocommunicationlink.

Apacket-switched

Bdata-switched

Ccircuit-switched

Dmessage-switched

42．Inacircuit-switchednetwork,ifeachlinkhasncircuits,foreachlinkusedbytheend-to-endconnection,theconnectiongets（）ofthelink’sbandwidthforthedurationoftheconnection.

Aafraction1/n

Ball

C1/2

Dntimes

43．For（）,thetransmissionrateofacircuitisequaltotheframeratemultipliedbythenumberofbitsinaslot.

ACDMA

Bpacket-switchednetwork

CTDM

DFDM

44．（）meansthattheswitchmustreceivetheentirepacketbeforeitcanbegintotransmitthefirstbitofthepacketontotheoutboundlink.

AQueuingdelay

BStore-and-forwardtransmission

CPacketloss

DPropagation

45．Thenetworkthatforwardspacketsaccordingtohostdestinationaddressesiscalled（）network.

Acircuit-switched

Bpacket-switched

Cvirtual-circuit

Ddatagram

46．Thenetworkthatforwardspacketsaccordingtovirtual-circuitnumbersiscalled（）network.

Acircuit-switched

Bpacket-switched

Cvirtual-circuit

Ddatagram

47．Inthefollowingentries,whichisnotakindofaccessnetwork?

（）

Aresidentialaccess

Bcompanyaccess

Cwirelessaccess

Dlocalaccess

48．Supposethereisexactlyonepacketswitchbetweenasendinghostandareceivinghost.ThetransmissionratesbetweenthesendinghostandtheswitchandbetweentheswitchandthereceivinghostareR1andR2,respectively.Assumingthattheswitchusesstore-and-forwardpacketswitching,whatisthetotalend-to-enddelaytosendapacketoflengthL?

（Ignorequeuingdelay,propagationdelay,andprocessingdelay.）（）

AL/R1＋L/R2

BL/R1

CL/R2

Dnoneoftheabove

49．Thetimerequiredtoexaminethepacket’sheaderanddeterminewheretodirectthepacketispartofthe（）.

Aqueuingdelay

Bprocessingdelay

Cpropagationdelay

Dtransmissiondelay

50．Thetimerequiredtopropagatefromthebeginningofthelinktothen