ccna考试题目加强版

《ccna考试题目加强版》由会员上传分享，免费在线阅读，更多相关内容在工程资料-天天文库。

1、1.Whichoffollowingcorrectlydescribetheroutera.packetswitchingb.collisionpreventiononaLANsegmentc.packetfilteringd.broadcastdomainenlargemente.broadcastfowrodingf.internetworkcommunication2.whichofthefollowingcorrectlydescriblestheroleofthedeviceinawancdg?a.adigitallocalloopb.arou

2、teriscommonlyconsideredadeedevicec.amodemterminatesananlonglocalloopd.arouteriscommonlyconsideredadtedevicee.amodemterminatesadigitallocalloopf..aesu/dsuterminateananlonglocalloopg.amodemisusedtoterminateaT1simultaneous同时*pl4■一3pl6—1pl9…62009A15.oo做到第21页第九题Thecorporateheadofficeo

3、fTestKinghasateleconferencingsystemthatusesVOIP（voiceoverIP）technology.ThissystemusesUDPasthetransportforthedatatransmissions.IftheseUDPdatagramsarriveattheirdestinationoutofsequence,whatwillhappen?A.UDPwillsendanICMPInformationRequesttothesourcehost.B.UDPwillpasstheinformationin

4、thedatagramsuptothenextOSIlayerintheorderthattheyarrive.C.UDPwilldropthedatagrams.D.UDPwillusethesequencenumbersinthedatagramheaderstoreassemblethedatainthecorrectorder.E.UDPwillnotacknowledgethedatagramsandwaitforaretransmissionofthedatagrams.Answer:BExplanation:VOIPsystemsutili

5、zeUDPbecauseitisfasteranduseslessoverhead.Inaddition,thereliabletransportmechanismusedinTCPisuselesstoVOIPbecauseifapacketgetsdroppedandneedstoberesent,itwillbealreadytoolate.UDPprovidesaserviceforapplicationstoexchangemessages.UnlikeTCP,UDPisconnectionlessandprovidesnoreliabilit

6、y,nowindowing,andnoreorderingofthereceiveddata.However,UDPprovidessomefunctionsofTCP,suchasdatatransfer,segmentation,andmultiplexingusingportnumbers,anditdoessowithfewerbytesofoverheadandwithlessprocessingrequired.UDPdatatransferdiffersfromTCPdatatransferinthatnoreorderingorrecov

7、eryisaccomplished.ApplicationsthatuseUDParetolerantoflostdata,ortheyhavesomeapplicationmechanismtorecoverdataloss.P41—2p43-—3p50—7p53—1p60====6P63—9p74—-3p76—4（e选项）p79…2p80…3p82…・5路由器交换机的指示灯情况很重要。。。是欠缺。。。P86—1P86—2P88—4（未作）P91—3p94—6（线缆知识要看一下）P95—2P98—-4（关于IEEE标准的记忆）P100—7（全双工半双工

8、的知识也要看下）P101…9（e选项有问题）Pl02—10P102—11（以太网