CCNA(200-120)中文版题库对照

CCNA（200-120）题库中英对照整理于：2015年3月31日版本：1.2声明：本题库来源互联网（鸿鹄论坛）本题库为英文考试原版左右选择题中文考试为随机抽取英文题的中译版此题库非中文考试题库，而是英文题库手动翻译此题库为手工个人翻译，存在错误和不妥难免，不代表任何官方机构和组织本题库旨在更好的理解英文原本题库，也可以用于中文考试参考用。如发现任何错误或不当之处，可以自行修改，但请更新版本以免混乱，也可致上传者。QUESTION001Refertotheexhibit.WhatwillRouteridowhenitreceivesthedataframeshown?(Choosethree.)参照下图，这个图示显示了R1接受到如图所示数据帧的时候会怎么做？Router1#showiparpProtocolAddressHardwareAdddrTypeInterfaceInteiriet19246320590000.Dc07.fS92ARPAFastEthernet0/0Internet192.1636053ODOO.Dc07LacOOARPAFastEthernet0/1Internet192.l(5S.20.l0000.0c63.ae^5ARPAFastEthernet0/0Internet90000.0c07.4320ARPAFastE±emetD/2[ntemet192.ltiS.tfOJ-qoap.0c63,i3ooARPAFastE±emet0/lInternet192.16840.1-ARPAFa就Ethernet%DataFrame:SourceMACSourceIPDestinationMACDestinationIPSourceMACSourceIPDestinationMACDestinationIP0000.Oc07.fB92 19216820.5 0000.0c63,ae45 19216840.5RouteriwillstripoffthesourceMACaddressandreplaceitwiththeMACaddress0000.0c36.6965.RI会剥离源MAC地址，以0000:0C36.6965代替。RouteriwillstripoffthesourceIPaddressandreplaceitwiththeIPaddress.RI会剥离源IP地址，以代替。Router1willstripoffthedestinationMACaddressandreplaceitwiththeMACaddress0000.0c07.4320.RI会剥离源MAC地址，以0000:0C36.6965代替。Router1willstripoffthedestinationIPaddressandreplaceitwiththeIPaddressof.RI会剥离目的IP地址，以代替。Router1willforwardthedatapacketoutinterfaceFastEthernet0/1.R1将会从F0/1转发这个数据包。Router1willforwardthedatapacketoutinterfaceFastEthernet0/2 .R1将会从F0/2转发这个数据包数据传输过程中，IP地址不变，但是在不同的网段中，MAC地址要根据设备的具体情况而发生改变。 在不同网络中，依靠IP地址定位，在同一网络中，依靠MAC地址定位。QUESTION002Refertotheexhibit.WhichthreestatementscorrectlydescribeNetworkDeviceA?(Choosethree.)如图所示，关于网络设备A哪三项是正确的描述？

A.Withanetworkwidemaskof28,eachinterfacedoesnotrequireanIPaddress.如果配置一个25位的网络号，每个端口不需要配置一个地址。B.Withanetworkwidemaskof28,eachinterfacedoesrequireanIPaddressonauniqueIPsubnet.如果配置一个25位的网络号，每个端口需要配置一个地址和子网。C.Withanetworkwidemaskof,communicatewitheachother.如果配置一个24位的网络号，成为一个二层设备以便让C.Withanetworkwidemaskof,communicatewitheachother.如果配置一个24位的网络号，成为一个二层设备以便让D.Withanetworkwidemaskof,communicatewitheachother.如果配置一个24位的网络号，成为一个三层设备以便让mustbeaLayer2deviceforthePC和其他设备通讯。mustbeaLayer3deviceforthePC和其他设备通讯。PCstoPCstoE.Withanetworkwidemaskof,eachinterfacedoesnotrequireanIPaddress如果配置一个23位的网络号，每个端口不需要配置一个地址。oftheQUESTION003oftheWhichlayerintheOSIreferencemodelisresponsiblefordeterminingtheavailabilityreceivingprogramandcheckingtoseeifenoughresourcesexistforthatcommunication?在OSI参考模型当中，哪一层可以判断程序的可用性以机是否有足够的资源来支持这个通讯?transport 传输层network 网络层presentation表示层session 会话层application 应用层QUESTION004WhichofthefollowingdescribestherolesofdevicesinaWAN?(Choosethree.)下列哪些描述广域网设备的作用？ACSU/DSUterminatesadigitallocalloop联系数字本地环路AmodemterminatesadigitallocalloopACSU/DSUterminatesananaloglocalloopAmodemterminatesananaloglocalloop一个模拟信号ArouteriscommonlyconsideredaDTEdevice路由器通常是DTE设备ArouteriscommonlyconsideredaDCEdevice路由器通常是DCE设备QUESTION005Refertotheexhibit,HostApingsinterfaceS0/0onrouter3,whatistheTTLvalueforthatping?如图所示，主机A的ping路由器3的S0/0接口，TTL值会是多少？HOStAA.253B.252C.255D.254QUESTION006AnetworkadministratorisverifyingtheconfigurationofanewlyinstalledhostbyestablishinganFTPconnectiontoaremoteserver.Whatisthehighestlayeroftheprotocolstackthattheneworkadministratorisusingforthisoperation?网络管理员验证的配置是一个新安装的主机通过建立 FTP连接到远程服务器。网络管理员这个操作使用的最高协议层是什么？applicationpresentationsession

transportinternetdatalinkFTP协议属于应用层QUESTION007Refertotheexhibit.AfterHostApingsHostB,whichentrywillbeintheARPcacheofHostAtosupportthistransmission?如图所示，主机A ping主机B,在此通信中，以下哪个列表将会进入主机 A的ARP缓存?Fa(W1Refertotheexhibit.AfterHostApingsHostB,whichentrywillbeintheARPcacheofHostAtosupportthistransmission?如图所示，主机A ping主机B,在此通信中，以下哪个列表将会进入主机 A的ARP缓存?Fa(W11P-19Z158A6/24MAC-00012405-2425FaO/24MQaoOOL7485.89IEHo^tAFaWOIP-192.168.6J^24MAC*OODf.24加M16IP-10.12.6130MAC-000f.2405.2424-1睨168.6.2124HostB*192168.6.273MAC-OQ1O5aOc.fdH6Gateway-192.163.6JIP-192468.4.7/24MAC-OOIO.SaOcJeaeGateway-*192168.6.273MAC-OQ1O5aOc.fdH6Gateway-192.163.6JIP-192468.4.7/24MAC-OOIO.SaOcJeaeGateway-B.C.B.C.InterfaceAddressPhysica^AddressType192.16847 000f,2480.8916dynamicInterfaceAddressPhysicalAddressType192.1684700lQ.5a0c.feaedynamicInterfaceAddressPhysicalAddressType - 1 工 I 192J68-6J 0010.5a0c.feaedynamicInterfaceAddressPhysicalAddressType19216861000t2480.8916dynamicE.InterfaceAddressPhysicalAddressType

InterfaceAddressPhysicalAddressType192J68.6.2 001Q.5a0cJeaedynamicF.QUESTION008Anetworkinterfaceporthascollisiondetectionandcarriersensingenabledonasharedtwistedpairnetwork.Fromthisstatement,whatisknownaboutthenetworkinterfaceport?在一个双绞线网络中的一个网络接口上监测到网络冲突，冲这个表述中，有关这个网络接口，哪一项是正确的？Thisisa10Mb/sswitchport.Thisisa100Mb/sswitchport.ThisisanEthernetportperatingathalfduplex.ThisisanEthernetportoperatingatfullduplex.ThisisaportonanetworkinterfacecardinaPC.半双工模式会产生冲突，全双工模式不会产生冲突QUESTION009Areceivinghostcomputesthechecksumonaframeanddeterminesthattheframeisdamaged.Theframeisthendiscarded.AtwhichOSIlayerdidthishappen?收到一个主机发来的帧并进行校验以确认是否损坏，然后丢弃。这个过程在 OSI哪一层发生？sessionnetworkPhysicaldatalinkTransport传输层：数据段，segment网络层：数据包，数据报，packet数据链路层：数据帧，frameQUESTION010WhichofthefollowingcorrectlydescribestepsintheOSIdataencapsulationprocess?(Choosetwo.)以下那些正确描述了OSI数据封装的过程？mayaddreliabilityandflowThetransportlayerdividesadatastreamintosegmentsandcontrolinformation.mayaddreliabilityandflow传输层将数据分段，并且加上可靠性和流控制信息。ThedatalinklayeraddsphysicalsourceanddestinationaddressesandanFCStothesegment.数据链路层会添加物理原和目的地址以及 FCS校验字段，然后给数据段Packetsarecreatedwhenthenetworklayerencapsulatesaframewithsourceanddestinationhostaddressesandprotocol-relatedcontrolinformation.当网络层封装数据帧的时候，添加源和目的主机地址已经协议控制信息，形成数据包。PacketsarecreatedwhenthenetworklayeraddsLayer3addressesandcontrolinformationtoasegment.网络层添加三层地址和控制信息给数据段，从而形成数据包。Thepresentationlayertranslatesbitsintovoltagesfortransmissionacrossthephysicallink.表示层会将数据转换成电平给物理链路传输。每一层只能接收来自上一层的数据并进行封装QUESTION011Refertothegraphic.HostAiscommunicatingwiththeseiver.WhatwillbethesourceMACaddressoftheframesreceivedbyHostAfromtheserver?参考以下图片，主机A和服务器之间的通信，主机A收到服务器发来的数据帧，那么原MAC地址会是什么？theMACaddressoftheseivernetworkinterfacetheMACaddressofhostAtheMACaddressofrouterinterfacee1theMACaddressofrouterinterfacee0QUESTION012Refertotheexhibit.WhattworesultswouldoccurifthehubweretobereplacedwithaswitchthatisconfiguredwithoneEthernetVLAN?(choosetwo)如图所示，在一个以太网 VLAN中，如果集线器用交换机代替，将会出现哪两个结果？A.Thenumberofcollisiondomainswoulddecrease.冲突域将会减少Thenumberofcollisiondomainswouldincrease冲突域将会增加。Thenumberofbroadcastdomainswouldremainthesame.广播域不会改变Thenumberofcollisiondomainswouldremainthesame.冲突域不会改变Thenumberofbroadcastdomainswouldincrease.广播域将会增加。QUESTION013Whichthreestatementsaccuratelydescribelayer2Ethernetswitches?(choosethree)下列哪三项准确的描述了二层以太网交换机？Microsegmentationdecreasesthenumberofcollisionsonthenetwork.在网络中，网络分段减少了冲突的数量。ifaswitchreceivesaframeforanunkowndestination,itusesARPtoresolvetheaddress.如果一个交换机接受到一个未知目的帧，他们使用 ARP来决定这个地址。SpanningTreeProtocolallowsswitchestoautomaticallysharevlaninformation.生成树协议允许交换机自动分享 vlan信息。Inaproperlyfunctioningnetworkwithredundantswitchedpaths,eachswitchedaegmentwillcontainonerootbridgewithallitsportsintheforwardingstate.Allotherswitchesinthatbroadcastdomainwillhaveonlyonerootport.在一个具有冗余链路的交换网络中，会包含一个根桥，且每个端口都处于转发状态，在这个广播域中，其他交换机有且只有一个根端口。Establishingvlansincreasesthenumberof broadcastdomains.创建vlan能够增大广播域数量。Switchesthatareconfiguredwithvlansmakeforwardingdecisionsbasedonbothlayer2andlayer3addressinformation.交换机的vlan策略配置，是基于二层和三层地址。QUESTION014WheredoesroutingoccurwithintheDoDTCP/IPreferencemodel?在DOD的TCP/IP参考模型中，路由发生在哪一层？applicationinternetnetworktransportDoD模型：应用层(Application)主机到主机层(HosttoHost)网络互连层(Internet)网络访问层(NetworkAccess)OSI模型：物理层(Physical)数据链路层(DataLink)网络层(Network)传输层(Transport)会话层(Senssion)表示层(Presentation)应用层(Application)QUESTION015WhichdestinationaddresseswillbeusedbyHostAtosenddatatoHostC?(Choosetwo.)主机A发送数据到主机C,会使用哪个目的地址?Ho$1AHost8theIPaddressofSwitch1theMACaddressofSwitch1theIPaddressofHostCD.theMACaddressofHostCtheIPaddressoftherouter'sE0interfacetheMACaddressoftherouter'sE0interfaceQUESTION016ForwhattwopurposesdoestheEthernetprotocolusephysicaladdresses?(Choosetwo.)使用武力地址的两个目的是什么？touniquelyidentifydevicesatLayer2在二层上识别设备。toallowcommunicationwithdevicesonadifferentnetwork在不同的网络中允许通讯。todifferentiateaLayer2framefromaLayer3packet区分来自三层的包和二层的帧。toestablishaprioritysystemtodeterminewhichdevicegetstotransmitfirst创立一个优先级系统以便确定哪个设备可以优先传输。toallowcommunicationbetweendifferentdevicesonthesamenetwork同一个网络中允许不同的设备通讯。toallowdetectionofaremotedevicewhenitsphysicaladdressisunknown当物理地址未知的时候，允许远端设备检测。QUESTION017Refertotheexhibit.Basedontheinformationgiven.Whichswitchwillbeelectedrootbridgeandwhy?如图所示，以图示信息，哪个交换机将会被选举为根桥，为什么？SwitchA,becauseithasthelowestMACaddress交换机A,因为它具有更低的MAC地址。SwitchC,becauseithasthelowestpriority交换机C,因为它具有更低的优先级。SwitchB,becauseithasthehighestMACaddress交换机B,因为它具有更高的MAC地址。SwitchC,becauseitisthemostcentrallylocatedswitch交换机C,因为它最处于交换机的中心。SwitchA,becauseitisthemostcentrallylocatedswitch交换机A,因为它最处于交换机的中心。SwitchD,becauseithasthehighestpriority交换机D,因为它具有更高的优先级。根桥的选举关键在于比较桥 ID（优先级+MAC地址）大小，小者为根桥QUESTION018Whatvalueisprimarilyusedtodeterminewhichportbecomestherootportoneachnonrootswitchinaspanning-treetopology?在非根桥的交换机上，如果要选择根端口，哪个值是最常用的？？lowestportMACaddress更小的MAC地址。portprioritynumberandMACaddress.优先级号和MAC地址。VTPrevisionnumberVTP版本号。highestportprioritynumber.更高的端口优先级号。pathcost路径开销。根端口的选择依据是到达根桥开销最小的端口，如果开销相同则找端口 ID最小的端口QUESTION019Refertotheexhibit.Switch-1needstosenddatatoahostwithaMACaddressof00b0.d056.efa4.WhatwillSwitch-1dowiththisdata?如图所示，交换机1需要发送数据给一个MAC地址为 00b0.d056.efa4的主机，交换机1如何处理这个数据？Swtch-1#showaddress-tableTOC\o"1-5"\h\zDynamicAddressesCount 3SecureAddresses(User-defined)CountUStaticAddr&sses(User-defined)Count0\o"CurrentDocument"SystemSelfAddressesCount: 41TQtalMacaddresses: SONoivstaticAddressTable:□estination.AddressAdTypeVLANDestinationPort001Q,CdetJ.e289 Dynamic 1 FastEthemeffl/101110.7bOCt1540 Dynamic 2 Fa^tEthemetfl/30010.TbOO.1545 Dynamic 2 FastEthemetO/2switch-1willdropthedatabecauseitdosenothaveanentryforthatMACaddress交换机1会终止这个数据因为它不在此 MAC地址中。。switch-1willfloodthedataoutallofitsportfromwhichthedataoriginated交换机 1发送给所有端口出了数据来源端口。switch-1willforwardthedatatoitsdefaultgateway交换机 1会转发这个数据给默认网关。E.switch-1willsendanARPrequestoutallitsportsexcepttheportfromwhichthedataoriginated交换机1发送一个ARP请求给所有端口出了数据来源端口。ARP(IP MAC)QUESTION020Whatisthefunctionofthecommandswitchporttrunknativevlan999 onaswitch?在交换机上 switchporttrunknativevlan999 这个命令的作用是？ItdesignatesVLAN999foruntaggedtraffic.没有标记的流量都打上 vlan999。ItblocksVLAN999trafficfrompassingonthetrunk.阻塞VLAN999从这个链路通过ItcreatesaVLAN999interface.创立 vlan999端口。ItdesignatesVLAN999asthedefaultforallunkowntaggedtraffic.制定所有的未知标记帧为 VLAN999。本征vlan都是不打标记的。QUESTION021Whichtwoprotocolsareusedbybridgesand/orswitchestopreventloopsinalayer2network?(Choosetwo.)哪两个协议是用于二层网络下的交换机和网桥，防止环路产生的协议？802.1dVTP802.1qSTPSAPQUESTION022WhichswitchwouldSTPchoosetobecometherootbridgeintheselectionprocess?在STP选举过程中，哪个交换机将会成为根桥？A.32768:11-22-33-44-55-66B.32768:22-33-44-55-66-77C.32769:11-22-33-44-55-65D.32769:22-33-44-55-66-78依据：交换机的ID=优先级+MAC地址优先级必须是 4096的整倍数+Vlan号QUESTION023Aswitchisconfiguredwithallportsassignedtovlan2withfullduplexFastEthernettosegmentexistingdepartmentaltraffic.WhatistheeffectofaddingswitchportstoanewVLANontheswitch?一个交换机的所有端口分配在VLAN2里，且使用的是全双工快速以太网。现在把交换机的端口划分到新的vlan中会发生什么？Morecollisiondomainswillbecreated.更多的冲突域将会创建。IPaddressutilizationwillbemoreefficient.IP地址利用率将会更有效。Morebandwidthwillberequiredthanwasneededpreviously.比以前需要更多的带宽。Anadditionalbroadcastdomainwillbecreated .一个额外的广播域将会创建。QUESTION024Whatarethreebenefitsofimplementingvlans?(choosethree)实施vlan有哪三项好处？Amoreefficientuseofbandwidthcanbeachievedallowingmanyphysicalgroupstousethesamenetworkinfrastructure一个更有效利用带宽，这样可以允许更多的物理组使用同一个网络基础设施。Broadcaststormscanbemitigatedbydecreasingthenumberofbroadcastdomains,thusincreasingtheirsize.广播风暴会被抑制，通过减小广播域的数量和增大广播域的大小。Ahigherlevelofnetworksecuritycanbereachedbyseparatingsensitivedatatrafficfromothernetworktraffic.通过分割不同的网络数据从而达到更高的网络安全。Port-basedvlansincreaseswitch-portuseefficient,thanksto802.1Qtrunks基于端口的vlan提高了交换机端口的使用效率，由于采用的是 802.1Q。Amoreefficientuseofbandwidthcanbeachievedallowingmanylogicalnetworkstousethesamenetworkinfrastructure.一个更有效利用带宽，这样可以允许更多的逻辑组组使用同一个网络基础设施。Broadcaststormscanbemitigatedbyincreasingthenumberofbroadcastdomains,thusreducingtheirsize.广播风暴会被抑制，通过增大广播域的数量和减少广播域的大小。VLANsmakeiteasierforITstafftoconfigurenewlogicalgroups,becausethevlansallbelongtothesamebroadcastdomain.Vlan使得管理员更简易的配置新的逻辑分组，因为这个 vlan都是属于同一广播域中。QUESTION025WhichIEEEstandardprotocolisinitiatedasaresultofsuccessfulDTPcompletioninaswitchoverFastEthernet?下列哪一个 IEEE标准协议是一个快速以太网交换机中DTP过程的结果？802.3ad802.1w802.1Q802.1dQUESTION026WhichofthefollowingarebenefitsofVLANs?(Choosethree.)下列哪三项是 vlan的好处？Theyincreasethesizeofcollisiondomains.他们增加了冲突域的大小。Theyallowlogicalgroupingofusersbyfunction.他们允许根据使用者功能进行逻辑分组。Theycanenhancenetworksecurity.他们能提高网络安全性。Theyincreasethesizeofbroadcastdomainswhiledecreasingthenumberofcollisiondomains.他们增加了广播域的大小，并减少冲突域的数量。Theyincreasethenumberofbroadcastdomainswhiledecreasingthesizeofthebroadcastdomains.他们增加了广播域的数量并减少了广播域的大小。Theysimplifyswitchadministration.他们简化了管理。QUESTION027Refertotheexhibit.AtechnicianhasinstalledSwithchBandneedstoconfigureitforremoteaccessfromthemanagementworkstationconnectedSwitchAWhichsetofcommandsisrequiredtoaccomplishthistask?如图所示，一个技术员已经安装好交换机 B和配置它使能通过交换机 A远程访问并且管理，那个命令是可以完成这个任务的？

51.24 192J68.8.25424Mmagein^iit

WorkstationSwitchB(config)#interfaceFastEthernet0/1SwitchB(config)#ipaddress52SwitchB(config)#noshutdownSwitchB(config)#ipdefault-gateway54SwitchB(config)#interfacevlan1SwitchB(config)#ipaddress52SwitchB(config)#noshutdownSwitchB(config)#interfacevlan1SwitchB(config)#ipaddress52SwitchB(config)#ipdefault-gateway54SwitchB(config)#noshutdownSwitchB(config)#ipdefault-network54SwitchB(config)#interfacevlan1SwitchB(config)#ipaddress52SwitchB(config)#noshutdownQUESTION028InanEthernetnetwork,underwhattwoscenarioscandevicestransmit?(Choosetwo.)在以太网中，哪两种情况，设备可以传输数据？whentheyreceiveaspecialtoken当接受到一个特定的令牌时whenthereisacarrier当有一个载体的时候whentheydetectnootherdevicesaresending没有检测到其他设备在发送数据whenthemediumisidle当传输介质为空闲状态whentheservergrantsaccess当服务器允许访问的时候载波侦听多路访问/冲突检测(CSMA/CD)QUESTION029WhichtwostatesaretheportstateswhenRSTPhasconverged?(choosetwo)当RSTP收敛的时候，端口会处于哪两种状态？blockinglearningdiscardingforwardinglisteningQUESTION030Whichtwocommandscanbeusedtoverifyatrunklinkconfigurationstatusonagivenciscoswitch?(choosetwo)那两个命令被用来在思科交换机上查看中继链路？showinterfacesinterfaceshowinterfacestrunkshowinterfacesswitchportshowipinterfacebriefshowinterfacesvlanQUESTION031WhichcommandenablesRSTPonaswitch?在交换机上使用哪条命令开启 RSTP？spanning-treemoderapid-pvstspanning-treeuplinkfastspanning-treebackbonefastspanning-treemodemstQUESTION032Whichofthefollowingstatementsdescribethenetworkshowninthegraphic?(Choosetwo.)在下图表中，有关描述正确的是？Therearetwobroadcastdomainsinthenetwork这个网络有两个广播域。Therearefourbroadcastdomainsinthenetwork.这个网络有4个广播域。Therearesixbroadcastdomainsinthenetwork.这个网络有6个广播域。Therearefourcollisiondomainsinthenetwork.这个网络有4个冲突域。Therearefivecollisiondomainsinthenetwork.这个网络有5个冲突域。Therearesevencollisiondomainsinthenetwork.这个网络有7个冲突域。QUESTION033Refertotheexhibit.SwitchASwitcfiMshowrunnitig-configBuildingconfiguration..,SwitchASwitcfiMshowrunnitig-configBuildingconfiguration..,^outputarnitted>Currentconfiguralion:100bytesiinterfaceFastEthern?tO/24switchportmocieaccessnoipaddressI^outputomittediendSwitchB#showrunning-confiyAuildingconfigutation...^outputomitted%Currentconfiguration:10Obytes!interfaceFasi^therne1D(Xswitcnportmcideaccessipadtiress।*^outputomitted^endAllswitchportsareassignedtothecorrectVLANs,butnoneofthehostsconnectedtoSwitchAcancommunicatewithhostsinthesameVLANconnectedtoSwitchB.Basedontheoutputshown,whatisthemostlikelyproblem?如图所示，所有的交换机端口已经正确的配置在同一个 vlan下。但是交换机A上的所有主机都不能和处于同一vlan下的交换机B上的主机通信，根据输入，最有可能的问题出现在？TheaccesslinkneedstobeconfiguredinmultipleVLANs.Access链路必须配置成多条vlan。ThelinkbetweentheswitchesisconfiguredinthewrongVLAN.两个交换机之间的链路配置在错误的 VLAN中。Thelinkbetweentheswitchesneedstobeconfiguredasatrunk.两个交换机之中应该配置为 trunk链路。VTPisnotconfiguredtocarryVLANinformationbetweentheswitches.VTP是不能在两台交换机之间传输 vlan的的。SwitchIPaddressesmustbeconfiguredinorderfortraffictobeforwardedbetweentheswitches交换机IP必须配置以便在两台交换机之间交换机信息。QUESTION034Refertotheexhibit.GiventheoutputshownfromthisCiscoCatalyst2950,whatisthemostlikelyreasonthatinterfaceFastEthernet0/10isnottherootportforVLAN2?如下图所示为思科Catalyst2950交换机的输入信息，端口f0/10没有成为vlan2的根端口的最有可能原因是什么？Switch#showspanning-treeinterfacefastethernet0/10Vian RoleStsCossPrio.NbrTypeVLAN3001 Root FWD 19 126.1 P2pVLAN30C2 Mtn BTE 19 12G.2 P2pV1AN3003 Root FWD 19 12E.2 PZpThisswitchhasmorethanoneinterfaceconnectedtotherootnetworksegmentinVLAN2.这个交换机有超过1个的端口和 vlan2的根桥直连。ThisswitchisrunningRSTPwhiletheelecteddesignatedswitchisrunning802.1dSpanningTree.当指定交换机运行802.1d生成树的时候，这个交换机是运行 RSTPoThisswitchinterfacehasahigherpathcosttotherootbridgethananotherinthetopology.在这个拓扑中，此交换机比其他交换机到根桥具有更高的开销。ThisswitchhasalowerbridgeIDforVLAN2thantheelecteddesignatedswitch.在vlan2中，这个交换机比指定交换机具有更低的桥 ID。QUESTION035Whywillaswitchneverlearnabroadcastaddress?为什么交换机不会学习到广播地址？Broadcastframesareneversenttoswiches.广播帧不能发送给交换机。Broadcastaddressesuseanincorrectformatfortheswitchingtable.交换缓存表中的广播地址使用一个错误的格式。Abroadcastaddresswillneverbethesourceaddressofaframe .一个广播地址不可能作为一个帧的原地址的。Broadcastsonlyusenetworklayeraddressing.广播只能使用在网络层。Abroadcastframeisneverforwardedbyaswitch.一个广播帧不会背交换机转发。QUESTION36Refertotheexhibit.WhyhasthisswitchnotbeenelectedtherootbridgeforVLAN1?如图所示，为什么这个交换机不能当选为 vlan1的根桥？Switch?shinFst)annincj-treevlan1VLAN10001SpanningRootIDtreeenabledPrlOEityAddte»CostPottSpanningRootIDtreeenabledPrlOEityAddte»CostPottHelloTikeptotocoirstp204B1QQQ8.217电,S8Q。381(FasCEthcKnctO/1)2secflaxAge20耳ecrForwardDelay1:BridgeItPtiorityAddressHelloTiaeAgingTiae33759(priori^OOOS.2C£e.660D2secHaK 2Dsec300sys-id-eKt1)ForwardDelayISSECsecInterfac&PoleStsCosePtio>NhcTypeInterfac&PoleStsCosePtio>NhcTypeFaO/1128,1FaO/1128,1FaO/4DesqFW38JFaO/liAXtxiBLK57FaO/13De5qFWD382P印即2PIthasmorethanoneinterfacethatisconnectedtotherootnetworksegment.超过一个接口连接在根网络断中。ItisrunningRSTPwhiletheelectedrootbridgeisrunning802.1dspanningtree.当选举根桥的时候，这个交换机运行 RSTP,而根桥运行的是802.1D生成树协议IthasahigherMACaddressthantheelectedrootbridge.它比根桥具有一个更高的 MAC地址。IthasahigherbridgeIDthantheelectedrootbridge.它比根桥具有一个更高的桥 ID。QUESTION037WhichtwolinkprotocolsareusedtocarrymultipleVLANsoverasinglelink?(Choosetwo.)下列那两个链路协议，被使用在单连璐中多 vlan之间的信息传输？VTP802.1q IEEE标准IGPISL 思科标准802.3uQUESTION038assumingthedefaultswitchconfigurationwhichvlanrangecanbeaddedmodifiedandremovedonaciscoswitch?在一台采用默认配置的思科交换机上，能进行修改你和操作的 vlan区间是？A. 2through1001B. 1through1001C. 1through1002D.2through1005QUESTION039Whichstatementaboutvlanoperationonciscocatalystswitchesistrue?下列哪一项关于思科catalyst交换机中vlan的描述是正确的？whenapacketisreceivedfroman802.1Qtrunk,thevlanidcanbedeterminedfromthesourceMACaddresstable.当接受到一个来自802.1Q链路的数据包时，vlan号是依靠源MAC地址表来确定的。unkownunicastframesareretransmittedonlytotheportsthatbelongtothesamevlan未知的单播帧只在相同的 vlan端口之间传播。portsbetweenswitchesshouldbeconfiguredinaccessmodesothatvlanscanspanacrosstheports交换机端口之间应该配置成 access模式，以便vlan之间能穿过端口。broadcastandmulticastframesareretransmittedtoportsthatareconfiguredondifferentvlan.广播和多播帧，可以通过配置转发到不同的 vlan当中。QUESTION040Refertothetopologyshownintheexhibit.WhichportswillbeSTPdesignatedportsifallthelinksareoperatingatthesamebandwidth?(Choosethree.)如下图所示拓扑中，所有端口都处在相同带宽中，那些端口将被STP作为指定端口？MAC:OrOO.Oace.ODCK>defaultpriorityMAC:Df00.cate.1111MAC:OfOOJd^e.OOOOdefaultpriofrty defauhpii<»fitySwitchA-Fa0/0SwitchA-Fa0/1SwitchB-Fa0/0SwitchB-Fa0/1SwitchC-Fa0/0SwitchC-Fa0/1QUESTION041Refertotheexhibit.HowshouldtheFastEthernet0/1portonthe2950modelswitchesthatareshownintheexhibitbeconfiguredtoallowconnectivitybetweenalldevices?如图所示，相关配置如下，请问在2950的f0/1端口上应该如何配置才能让所有设备互通?fUuterl%MM/24VLAN1faO.U,1OW2.16Q40.1/24VLAN10fa0/0JO1S2.1C8.2O.1/24VLAN20§wi*ch1IPaddress:1 16Q.1.2/24Ports3-12ULAN10Ports13-24VLAH20Sw血hZIPaddress:192.168J3/24Ports2-12VLAN10Ports13^4VLAN20Theportsonlyneedtobeconnectedbyacrossovercable.SwitchX(config)#interfaceFastEthernet0/1SwitchX(config-if)#switchportmodetrunkSwitchX(config)#interfaceFastEthernet0/1SwitchX(config-if)#switchportmodeaccessSwitchX(config-if)#switchportaccessvlan1SwitchX(config)#interfaceFastEthernet0/1SwitchX(config-if)#switchportmodetrunkSwitchX(config-if)#switchporttrunkvlan1SwitchX(config-if)#switchporttrunkvlan10SwitchX(config-if)#switchporttrunkvlan20QUESTION042RefertotheexhibitAframeonvlan1onswitchs1issenttoswitchs2whentheframeisreceivedonvlan2,whatcausesthisbehavior?如图所示，一个处于vlan1的交换机S1发送帧到交换机S2的vlan2中，会发生什么？

192.160.2,190.20卜a51VLAN1A.trunkmodemismatchestrunk模式不匹配。B.vlansthatdonotcorrespondtoauniqueIPsubnetvlan相当于一个独立的IP子网C.nativevlanmismatches本征vlan不匹配D.allowingonlyvlan2onthedestination.目的地只允许vlan2.QUESTION043interfacetnjrrkPortModeErcapsu:^lianStatusNative^larFa0/1on6021qtrvnkirrg2WhichthreestatementsaboutRSTParetrue?(choosethree)下列关于RSTP描述中哪三项是正确的？A.RSTPsignificantlyreducestopologyreconvergingtimeafteralinkfailure.192.160.2,190.20卜a51VLAN1A.trunkmodemismatchestrunk模式不匹配。B.vlansthatdonotcorrespondtoauniqueIPsubnetvlan相当于一个独立的IP子网C.nativevlanmismatches本征vlan不匹配D.allowingonlyvlan2onthedestination.目的地只允许vlan2.QUESTION043interfacetnjrrkPortModeErcapsu:^lianStatusNative^larFa0/1on6021qtrvnkirrg2WhichthreestatementsaboutRSTParetrue?(choosethree)下列关于RSTP描述中哪三项是正确的？A.RSTPsignificantlyreducestopologyreconvergingtimeafteralinkfailure.在一条链路失效的时候，RSTP能有效的降低拓扑聚会时间intEqbtrunkPortModeEncapsulationStatusF且出1 an 802」qtrunkingNativedan1ViansalloA&dontrtnk1*1005PortFaOi1Viansallowedendactiveirmarageinentdorram1t2PortF剂1Viansallowedortrurik1-1005Viansallowedandactiveinmanagennertdomain12VLAN2192.16B.2J72C2G192168102/292口3VLAN1FflC-2192.166.186/29匕』0用RSTPexpendstheSTPportrolesbyaddingthealternateandbackuproles.RSTP在STP的角色基础上增加了alternate和bakup端口。RSTPportsatatesareblocking,discarding,learing,orforwarding.RSTP端口定义有：blocking、discarding、learing和forwarding。RSTPalsousestheSTPproprsal-agreementsequence.RSTP也使用STPproprsal-agreement序列。RSTPusethesametimer-baseedprocessasSTPonpoint-to-pointlinks.在点到点的链路中RSTP使用与STP一样的间隔时间。RSTPprovidesafastertransitiontotheforwardingstateonpoint-to-pointlinksthanSTPdoes.在点到点的链路中， RSTP比STP提供更快速度使端口进入转发状态。QUESTION 044AtwhichlayeroftheOSImodelisRSTPusedtopreventloops?RSTP使用OSI的哪一层来组织环路？datalink数据链路层network网络层physical物理层transport传输层QUESTION045WhatdoseaLayer2switchusetodecidewheretoforwardareceivedframe?一个二层交换机如何确定收到的帧发哪里转发？sourceMACaddress源MAC地址。sourceIPaddress源IP地址。sourceswitchport源端口。destinationIPaddress目的IP地址。destinationportaddress目的端口地址。destinationMACaddress目的MAC地址。

QUESTION046Refertotheexhibit.Whichstatementistrue?如图所示，哪个描述是正确的？3w£tchAfr近ho—spaimS,ng-treevlaxi20VLAEDG20SpanningRootIDtreeenabled

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FortHeLIJTi.icicVLAEDG20SpanningRootIDtreeenabled

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FortHeLIJTi.icicprotocolrstp£45960017t556d.2a00Mg11(FaotEthomQtO'10J2二uuI4ajt2kge20nu匚Foxwa±tlDe2.ay15nuUBridgeIDUjt二口上工BridgeIDUjt二口上工t■7口cHjzmsmHelloTz.me岸守二njT-me2fifcy2(priority2JEJ20017.5964,158023ecMaxAqe2C'b-eg300sys-id-ext:1)FcrwazrdDelay15secRoleSt3CootraO/11FaJ/12raO/11FaJ/12R口。二FWD19AdtnBLRISTheFa0/11roleconfirmsthatSwitchAistherootbridgeforVLAN20.交换机A的f0/11是vlan20的根桥角色。VLAN20isrunningthePerVLANSpanningTreeProtocol.Vlan20运行了STP协议。TheMACaddressoftherootbridgeis0017.596d.1580.根桥的MAC地址是0017.596d.1580.SwitchAisnottherootbridge,becausenotalloftheinterfacerolesaredesignated.交换机A不是根桥，因为并非所有的端口都是指定端口。QUESTION047WhichtwobenefitsareprovidedbycreatingVLANs?(Choosetwo.)建立vlan具有哪两项好处？addedsecurity增加安全性。dedicatedbandwidth专用带宽。providessegmentation提供网络分段。allowsswitchestoroutetrafficbetweensubinterfaces允许交换机和路由器通过子接口联系。containscollisions包含冲突。QUESTION048WhichcommandcanbeusedfromaPCtoverifytheconnectivitybetweenhoststhatconnectthroughaswitchinthesameLAN?在同一个局域网内的一台交换机上，下列哪一个命令能用来检测主机之间的连通性？pingaddresstracertaddresstracerouteaddressarpaddressQUESTION049Basedonthenetworkshowninthegraphicwhichoptioncontainsthepotentialnetworkingproblemandprotocolorsettingthatcantopreventtheproblem?参照如图所示图表，哪一个选项可以包含了潜在的网络问题，以及协议或是能组阻止这个问题？Routingloops,holddowntimers路由