軟件水平考試網絡工程師英語復習練習題10套第1套ISDN,whichstandsforIntegratedServicesDigitalNetwork,isasystemofdigitalphoneconnections,whichhasbeenavailableforoveradecade.Thissystemallowsdatatobetransmittedsimultaneouslyacrosstheworldusing(1)digitalconnectivity.WithISDN,voiceanddataarecarriedbybearerchannelsoccupyingabandwithof(2)(bitspersecond).SomeswitcheslimitBchannelstocapacityof56Kbps.Adatachannel(3)handlessignalingat16Kbpsor64Kbps,dependingon(4).Notethat,inISDNterminology,”k”means(5),andnot1024(2^10)asinmanycomputerapplications.therefore,a64Kbpschannelcarriesdataatarateof64000bps.Anewsetofstandardprefixeshasrecentlybeencreatedtohandlethis.Underthisscheme,”K”(Kilo)means1000(10^3),”M”(Mega)means1000000(10^6),andsoon,and“Ki”(Kibi)means1024(2^10),”Mi”(Mebi)means1048576(2^20).andsoon。

(1).A.Multi-endsB.circleC.indirectD.end-to-end

(2).A.34KbpsB.84KbpsC.64KbpsD.54Kbps

(3).A.DchannelB.AchannelC.BchannelD.Cchannel

(4).A.themethodB.thenumberC.theservicetypeD.theusertype

(5).A.100000(10^5)B.1000(10^3)C.10000(10^4)D.100(10^2)答案:

1:D,2:C,3:A,4:C,5:B第2套Bluetoothisauniversalradiointerfaceinthe(1)frequencybandthatenablesportablecelectronicdevices(2)connectandcommunicate(3)viashortrange,adhocnetworks.Eachunitcansimultaneouslycommunicatewithupto(4)otherunitsperpiconet.Moreover,eachunitcansimultaneously(5)toseveralpiconets,BluetoothtechnologywhichapartfromEricsson,hasgainedthesupportofNokia,IBM,Toshiba,Intelandmanyothermanufactures,eliminatestheneedforwires,cablesandconnectorsforandbetweencordlessormobilephones,modems,headsets,PDAs,Computes,printers,progjectors,localaresnetworks,andsoon,andpavesthewayfornewandcompletelydifferentdevicesandapplications.(1).A.2.45GHzB.4.45GHzC.2.95GHzD.3.45GHz

(2).A.inB.onC.toD.with

(3).A.narrowlyB.wirelesslyC.freelyD.widely

(4).A.useB.severC.hostD.base

(5).A.relateB.addC.closeD.belong

答案:1:A,2:C,3:B,4:B,5:D第3套(1)isusedtoensuretheconfidentiality,integrityandauthenticityofthetwoendpointsintheprivatenetwork.the(2),anapplicationlayerprotocol,authenticateseachpeerinanIPsectransaction,IKEnegotiatessecuritypolicy,determiningwhichalgorithmmaybeusedtosetuptheRunnel.Italsohandlestheexchangofsessionkeysusedforthatonetransaction.Networksthatuse(3)tosecuredatatrafficcanautomaticallyauthenticatedevicesbyusing(4)whichVerifytheidentitiesofthetwouserswhoaresendinginformationbackandforth.IPseccanbeidealwaytosecuredatainlargenetworksthatrequire(5)connectionsamongmanydevices。(1)A.EncryptionB.CodeC.CertificateD.Tunnel

(2)A.associatedlinksB.InternetKeyExchangeCIPsecD.encryption

(3)AauthenticityB.passwordC.IPsecD.InternetKeyExchange

(4)A.protocolsB.keywordsC.IKED.digitalcertificates

(5)A.freeB.strictC.secureD.remote

答案:1:A,2:B,3:C,4:D,5:C第4套LAPBisa(1)protocolthatprovidescompletedatatransparencyina(2)operation.Itsupportsapeer-to-peerlinkinthatneitherendofthelinkplaystheroleofthepermanentmasterstation.HDLCLAPBisthe(3)thatisusuallyusedby(4),the(5)standardforPacketSwitchedNetworks.(1)A．bit-orientedsynchronousB．byte-orientedsynchronous

C．bit-orientedasynchronousD．byte-orientedasynchronous

(2)A．half-duplexpoint-to-pointB．half-duplexpoint-to-points

C．full-duplexpoint-to-pointD．full-duplexpoint-to-points

(3)A．PhysicalLayerB．LinkLayer

C．NetworkLayerD．TransportLayer

(4)A．X.21B．X.25C．X.28D．X.29

(5)A．ITUB．IEEEC．OSID．ANSI

答案:1:A,2:C,3:B,4:B,5:A第5套

Datacommunicationsequipment(DEC)(1)theserialdatastreamfromtheDTEandconvertsittosomeformof(2)suitableoftransmissiononvoicegradelines.Atthe(3),theDCEperformsthereversefunctionofconveringthereceivedanalogsignaltoserialdigitaldatastream.ThesimplestformofDCEisa(4)ordataset.Atthetransmitend,themodemcanbeconsideredaformof(5),whileatthereceiveend,itcanbeconsideredaformofanalogtodigitalconverter.Themostcommonformsofmodulationbymodemsarefrequencyshiftkeying(FSK),phaseshiftkeying(PSK),andquadratureamplitudemodulation(QAM).IfthecablesandsignallevelsusedtointerconnecttheDTEandDCEwereleftunregulated,thevariationsgeneratedwouldprobablybeproporationtothenumberofmanufactures.ElectronicsIndustriesAssociation(EIA),anorganizationofmanufactuuersconcernedwithestablishingindustrystandards,haveagreedontheRS-232CasthestandardinterfacebetweentheDTEandthemodem.Thisisa25pincablepinshavedesignatedfuntonsandspecifiedsignallevels.

(1)A.acceptsB.sendsC.deliversD.receives

(2)A.digitalsignalB.analogsignalC.lightsignalD.soundsignal

(3)A.backendB.frontendC.sendingendD.receiveend

(4)A.modemB.cpuC.demodulatorD.modulator.

(5)A.hostcomputerB.digitaltoanalogconverter

C.analogtodigitalconverterD.secondaries

答案:

1:A,2:B,3:D,4:A,5:B第6套InATM,cellsserveasuniversalunitsforallinformationtypes:data,voice,video,etc,Sinceswitchesknowbeforehandthesizeandformatofeachinformationunitsentthroughthenetwork,switcharchitecturescanbe1),Futhermore,sincetheCMSdeterminestheconnectionpathduringconnectionsetup,switchesdonothavetomakecomplexroutingdecisionsona(2)basis.Communiciationpathscanbe“hardwired”intotheswitch’scircuitstoenablefast,simpledecisions.Hardwaretechniques,usingVLSIbasedstatemachinesand,inthefuture,opticalswitchingtechniques,canbeappliedtoswitches.HardwareBasedswitchmatricestakeadvantageofallthese(3)characteristics.ThematrixapproachtoimplementingcellswitchinggreatlyincreasesthescalabilityofATMbasedsolutions,Onefundamentaladvantageofmatrixbasedswitchesisthat,asmoreportsareaddedtotheswitchingcomplex,theaggregateswitchingcapacityoftheswitchincreases.Inotherwords,as(4)areaddedtoaswitchednetwork,theytapintoanincreasingbandwidthpool-thecompleteoppositeofsharedmedianetworks,whereuserareforcedtosharesmallerandsmallerslicesofafixedamountof(5).Simplyput,cellswitchingbasedonATMenablesextremelyfast,massivelyscalablenetwordks.(1)A.optimizedB.increasedC.decreasedD.fixed

(2)A.cellbycellB.objectorientedC.bit-by-bitD.LAN

(3)A.VLSIB.OSIC.CMSD.ATM

(4)A.cellsB.switchesC.usersD.approaches

(5)A.dataB.mediaC.bandwidthD.information答案:1:A,2:A,3:D,4:C,5:C第7套Adigitalwalletis(1)thatenablesuserstopayforgoodsontheweb.Itholdscreditcardnumbersandother(2)suchasshippingaddress.Onceentered,thedataautomaticallypopulatesorderfieldsatmerchantsites.Whenusingadigitalwallet,consumersdon’tneedtofilloutorderformsoneachsitewhentheypurchaseanitembecausetheinformationhasalreadybeen(3)andisautomatically(4)andenteredintotheorderfieldsacrossmerchantsites.Consumersalsobenefitwhenusingdigitalwalletsbecausetheirinformationis(5)orprotechtedaprivatesoftwarecode.Andmerchantsbenefitbyreceivingprotectionagainstfraud.

(1)A.softwareB.hardwareC.deviceD.document

(2)A.cardsB.secretsC.publicinformationD.personinformation

(3)A.distributedB.storedC.addressedD.registered

(4)A.codedB.0updatedC.correctedD.named

(5)A.encryptedB.0updatedC.securedD.undiscovered

答案:1:A,2:D,3:B,4:B,5:A第8套Therouterinspectersthepacket’sIPaddressandperforms(1)lookuptoseeifthedestinationendstationresidesonthelocal(physicallyconnected)network,typicallycalledanIPsubber(2)usuallyisassigntedtoeachoftherouter’snetworkinterface.IfthedestinationIPaddressislocal,theroutersearchesaninternalstoreofIPaddressandlocal-deviceMediaAcessControl(MAC)address.Thisstoreisknownasthe(3)cache.AddressResolutionProtocol(ARP)istheuniversaltoolformatchingIPaddressestoMACaddress.Ifthedestination’sMACaddressappears,therouterinstallsthatMACaddressinthepachetheader(removingitsownMACaddressbecausethat’snolongerneeded)andsendsthepackettothedestionalendstation.IntheeventthatthedestionalMACaddressdoesnotappearintheARPcache-itmighthavetimedout,forinstance-theroutermustbroadcastanARPrequesttothesubnetreferencedbythepacket’sdestionalIPaddress.TheendstationwiththatIPaddressresponds,sendingbackitsMACaddress.Therouter0updatesitscache,installsthenewMACaddressintothe(4)andlaunchesthepacket.Iftheroutertablelookupshowsthatthepacketisdestinedforanonlocalsubnet,therouterforwardsthepackettothenext-hoprouterusingthe-hoprouter’sMACaddress.Routingtablesarecontinuouslybuiltandrebuiltbyintelligentdiscoveryprotocols,suchasRoutingInformationProtocolorOpenShortestPathFirst(OSPF).Eachrouter’sroutingtableshowsthebestroutetothedestinationaddress:foraddressthatmaybeseverdhopsaway,itshows(5)next-hoprouter.

(1)A.aroutertableB.asignalC.ane-mailD.afile

(2)A.ATCPsubnetB.IPheaderC.AnIPsubnetD.TCP/IP

(3)A.OSPFB.AddressResolutionProtocol(ARP)C.MACD.RIP

(4)A.smallpacketB.spaceC.packetheaderD.packettailor

(5)A.thefewestB.theworstC.theleastD.thebest

答案:1:A,2:C,3:B,4:C,5:D第9套_(1)__isusedtoensuretheconfidentiality,integrityandauthenticityofthetwoendpointsintheprivateetwork.the__(2)__,anapplicationlayerprotocol,authenticateseachpeerinanIPsectransaction,IKEnegotiatessecuritypolicy,determiningwhichalgorithmmaybeusedtosetuptheRunnel.Italsohandlestheexchangofsessionkeysusedforthatonetransaction.Networksthatuse__(3)__tosecuredatatrafficcanautomaticallyauthenticatedevicesbyusing__(4)__,whichVerifytheidentitiesofthetwouserswhoaresendinginformationbackandforth.IPseccanbeidealwaytosecuredatainlargenetworksthatrequire__(5)__connectionsamongmanydevices。(1)A.EncryptionB.CodeC.CertificateD.Tunnel

(2)A.associatedlinksB.I