CCNA（200-120）803题库V2.0(2014.10.08)-选择题

CCNA（200-120）803题库题库V2.0(2014.10.08)Number:200-120Passing Score:825Time Limit:120 minFile Version:v2.0CCNA（200-120）题库）题库V2.0（2014.10.8）CCNA 题库战报1000人超级QQ群:65330887CCNA 最新题库最新题库/最新战报最新战报 发布区：发布区：http:/ 鸿鹄论坛鸿鹄论坛 http:/CCNA考试报名1900，详情请联系鸿鹄全国区客服 QQ 613523101-613523109鸿鹄论坛官方淘宝店铺：http:/ 报名思科CCNA考试，送思科真实设备试验 http:/ 12.part 23.part 34.part 45.part 56.part 67.Drag n DropCCNA考试交流1000人QQ群：1504299912 0 1 4.1 0.8 更新内容：增加两道实验题OS P F Ne i、E I G R P T RCCNA考试交流1000人QQ群：65330887 Exam AQUESTION 1Refer to the exhibit.What will Router1 do when it receives the data frame shown?(Choose three.)A.Router1 will strip off the source MAC address and replace it with the MAC address 0000.0c36.6965.B.Router1 will strip off the source IP address and replace it with the IP address 192.168.40.1.C.Router1 will strip off the destination MAC address and replace it with the MAC address0000.0c07.4320.D.Router1 will strip off the destination IP address and replace it with the IP address of 192.168.40.1.E.Router1 will forward the data packet out interface FastEthernet0/1.F.Router1 will forward the data packet out interface FastEthernet0/2.Correct Answer:ACFSection:part 1ExplanationExplanation/Reference:考点：数据通信过程源目IP/mac地址的变化。Age(min)下面-为本地端口A：源MAC替换为f0/2口的mac，正确B：替换源IP，错误C：替换目的mac为下一跳入口的MAC，正确D：替换目的IP，错误E：从f0/1转发数据，错误F：正确-鸿鹄论坛http:/ 2Refer to the exhibit.Which three statements correctly describe Network Device A?(Choose three.)CCNA考试交流1000人QQ群：65330887 A.With a network wide mask of 255.255.255.128,each interface does not require an IP address.B.With a network wide mask of 255.255.255.128,each interface does require an IP address on a uniqueIP subnet.C.With a network wide mask of 255.255.255.0,must be a Layer 2 device for the PCs to communicatewith each other.D.With a network wide mask of 255.255.255.0,must be a Layer 3 device for the PCs to communicatewith each other.E.With a network wide mask of 255.255.254.0,each interface does not require an IP address.Correct Answer:BDESection:part 1ExplanationExplanation/Reference:如图，哪三个选项正确的描述了网络设备A？考点分析：这题考的是子网掩码的问题。使用掩码255.255.255.128和255.255.255.0时，两台主机的IP地址属于两个网段，所以A要用路由器（三层设备）才能通信，所以A设备每个接口需要设置IP地址。使用掩码255.255.254.0是，两台主机属于同一个网段，所以A要使用switch或hub就能通信，且不需要ip地址QUESTION 3Which layer in the OSI reference model is responsible for determining the availability of the receivingprogram and checking to see if enough resources exist for that communication?A.transportB.networkC.presentationD.sessionE.applicationCorrect Answer:ESection:part 1ExplanationExplanation/Reference:OSI中那一层负责决定一个进程的可用性并查看是否有可用的资源分给该进程？考点分析：OSI七层参考模型中负责决定一个进程的可用性并查看是否有可用的资源分给该进程是第七层应用层QUESTION 4Which of the following describes the roles of devices in a WAN?(Choose three.)A.A CSU/DSU terminates a digital local loopB.A modem terminates a digital local loopCCNA考试交流1000人QQ群：65330887 C.A CSU/DSU terminates an analog local loopD.A modem terminates an analog local loopE.A router is commonly considered a DTE deviceF.A router is commonly considered a DCE deviceCorrect Answer:ADESection:part 1ExplanationExplanation/Reference:SU/DSU是用于连接终端和数字专线的设备，属于DCE设备modem用于数字信号和模拟信号的转换，属于DCE设备路由器一般是DTE设备QUESTION 5Refer to the exhibit,Host A pings interface S0/0 on router 3,what is the TTL value for that ping?A.253B.252C.255D.254Correct Answer:ASection:part 1ExplanationExplanation/Reference:默认是255，每经过一个路由器减1QUESTION 6A network administrator is verifying the configuration of a newly installed host by establishing an FTPconnection to a remote server.What is the highest layer of the protocol stack that the nework administratoris using for this operation?CCNA考试交流1000人QQ群：65330887 A.applicationB.presentationC.sessionD.transportE.internetF.data linkCorrect Answer:ASection:part 1ExplanationExplanation/Reference:HTTP、FTP、TELNET、SNMP、DNS等服务都是在应用层QUESTION 7Refer to the exhibit.After HostA pings HostB,which entry will be in the ARP cache of HostA to support thistransmission?A.B.C.CCNA考试交流1000人QQ群：65330887 D.E.F.Correct Answer:DSection:part 1ExplanationExplanation/Reference:问：当主机A ping 主机B之后，下面那个ARP缓存条目会支持此次通讯？考题分析：这道题考的是局域网ARP的请求。Host A要ping Host B，首先Host A需要封装ping包，而封装ping包需要Host A和Host B的二、三层地址的信息。然而Host A不知道Host B的二层地址，这样Host A就会向局域网发送Arp请求，来请求Host B的二层地址。网关收到Host A的Arp请求后，发现Host B是其他网段的地址，这样网关会启用代理Arp的功能，将自己的二层地址应答给Host A。Host A收到应答包后会对本地的ARP缓存进行更新，将应答方的IP和MAC地址存储在ARP缓存中，同时完成ping包的封装。网关在收到ping包后会自动完成二层地址的重定向。所以答案是D。此题考查的是pc的arp表，不要和包的目的地址、源地址弄混了。在以太网寻址的时候，依靠的事MAC地址，每一个网段都需要寻找到自己的下一条（gateway）以自己的MAC作为source gateway的mac作为destination封装Frame，然后将Frame转发出去，但是数据包是不会进行变化的，也就是packet的头部信息不会发生改变。所以IP包头的source和des地址是不会变更的-鸿鹄论坛http:/ 8A network interface port has collision detection and carrier sensing enabled on a shared twisted pairnetwork.From this statement,what is known about the network interface port?A.This is a 10Mb/s switch port.B.This is a 100Mbs switch port.C.This is an Ethernet port operating at half duplex.D.This is an Ethernet port operating at full duplex.E.This is a port on a network interface card in a PC.Correct Answer:CSection:part 1ExplanationExplanation/Reference:考点：考查冲突域的概念。在半双工网络中才存在冲突域。综上所述选CQUESTION 9A receiving host computes the checksum on a frame and determines that the frame is damaged.Theframe is then discarded.At which OSI layer did this happen?A.sessionB.networkC.physicalD.data linkE.transportCCNA考试交流1000人QQ群：65330887 Correct Answer:DSection:part 1ExplanationExplanation/Reference:帧的处理是在二层QUESTION 10Which of the following correctly describe steps in the OSI data encapsulation process?(Choose two.)A.The transport layer divides a data stream into segments and may add reliability and flow controlinformation.B.The data link layer adds physical source and destination addresses and an FCS to the segment.C.Packets are created when the network layer encapsulates a frame with source and destination hostaddresses and protocol-related control information.D.Packets are created when the network layer adds Layer 3 addresses and control information to asegment.E.The presentation layer translates bits into voltages for transmission across the physical link.Correct Answer:ADSection:part 1ExplanationExplanation/Reference:传输层将数据分段，并且加入flow control等信息。在网络层就将数据进行打包，并加上ip包头，链路层。将包进行成Frame，封装二层头部-鸿鹄论坛http:/ 11Refer to the graphic.Host A is communicating with the seiver.What will be the source MAC address of theframes received by Host A from the server?A.the MAC address of the seiver network interfaceB.the MAC address of host A C.the MAC address of router interface e 1D.the MAC address of router interface e0CCNA考试交流1000人QQ群：65330887 Correct Answer:DSection:part 1ExplanationExplanation/Reference:host A收到server的帧的源mac地址是host A的网关的mac。QUESTION 12Refer to the exhibit.What two results would occur if the hub were to be replaced with a switch that isconfigured with one Ethernet VLAN?(choose two)A.The number of collision domains would decrease.B.The number of collision domains would increase.C.The number of broadcast domains would remain the same.D.The number of collision domains would remain the same.E.The number of broadcast domains would increase.Correct Answer:BCSection:part 1ExplanationExplanation/Reference:hub不可以隔离冲突域，所有端口同一个冲突域中，交换机可以隔离冲突域，每个端口在不同冲突域中，故换成交换机冲突域个数会增加，大小会减小，而hub 交换机都不可隔离广播域 所有端口都在同一个广播域中，故广播域数量不变A 冲突域数量减少B 冲突域数量增加 C 广播域数量不变D 冲突域数量不变E 广播域数量增加QUESTION 13Which three statements accurately describe layer 2 Ethernet switches?(choose three)A.Microsegmentation decreases the number of collisions on the network.B.if a switch receives a frame for an unkown destination,it uses ARP to resolve the address.C.Spanning Tree Protocol allows switches to automatically share vlan information.D.In a properly functioning network with redundant switched paths,each switched aegment will containCCNA考试交流1000人QQ群：65330887 one root bridge with all its ports in the forwarding state.All other switches in that broadcast domain willhave only one root port.E.Establishing vlans increases the number of broadcast domains.F.Switches that are configured with vlans make forwarding decisions based on both layer 2 and layer 3address information.Correct Answer:ADESection:part 1ExplanationExplanation/Reference:A为分割减少冲突的数量，这里是冲突并不是冲突域，正确B收到未知目的帧会产生泛洪C这是vtp的特性，不是stp的D在一个能够正常运行的网络冗余交换路径，每一个交换网段将包括一个跟桥。所有端口都在转发状态，其他本广播域的交换机有一个根端口。正确E.VLAN增加了广播域。正确F vlan使转发基于二层和三层IP。题目要求对2层交换机的描述，二层交换机不能基于3层IP转发QUESTION 14Where does routing occur within the DoD TCP/IP reference model?A.applicationB.internetC.networkD.transportCorrect Answer:BSection:part 1ExplanationExplanation/Reference:路由发生在DOD模型的哪一层？注意是DOD模型不是OSI模型QUESTION 15Which destination addresses will be used by Host A to send data to Host C?(Choose two.)A.the IP address of Switch 1B.the MAC address of Switch 1C.the IP address of Host CD.the MAC address of Host CE.the IP address of the routers E0 interfaceF.the MAC address of the routers E0 interfaceCCNA考试交流1000人QQ群：65330887 Correct Answer:CFSection:part 1ExplanationExplanation/Reference:数据包在转发的过程中，源目IP不变，源目MAC会变化。目的地不在同一个网段，数据先发送到网关。QUESTION 16For what two purposes does the Ethernet protocol use physical addresses?(Choose two.)A.to uniquely identify devices at Layer 2B.to allow communication with devices on a different networkC.to differentiate a Layer 2 frame from a Layer 3 packetD.to establish a priority system to determine which device gets to transmit firstE.to allow communication between different devices on the same networkF.to allow detection of a remote device when its physical address is unknownCorrect Answer:AESection:part 1ExplanationExplanation/Reference:考点：考查mac地址的作用。A：在二层唯一确定一台设备，正确B：是设备在不同的网络中通信，错误，不同网络通信需要通过IP地址确定。C：区别二层和三层帧，错误。D：确定设备的优先级，错误。没有这个功能。E：是同一网络的不同设备可以通信，正确F：当不知道远程设备的物理地址时可以查询，错误。不能跨网段。-鸿鹄论坛http:/ 17Refer to the exhibit.Based on the information given.Which switch will be elected root bridge and why?A.Switch A,because it has the lowest MAC addressB.Switch C,because it has the lowest priorityC.Switch B,because it has the highest MAC addressD.Switch C,because it is the most centrally located switchE.Switch A,because it is the most centrally located switchF.Switch D,because it has the highest priorityCorrect Answer:BSection:part 1CCNA考试交流1000人QQ群：65330887 ExplanationExplanation/Reference:选跟桥先比较优先级，优先级相同再比较mac地址大小QUESTION 18What value is primarily used to determine which port becomes the root port on each nonroot switch in aspanning-tree topology?A.lowest port MAC addressB.port priority number and MAC address.C.VTP revision numberD.highest port priority number.E.path costCorrect Answer:ESection:part 1ExplanationExplanation/Reference:此处为选举跟端口，先要比较到跟桥的cost。如果是选跟桥，先比较优先级QUESTION 19Refer to the exhibit.Switch-1 needs to send data to a host with a MAC address of 00b0.d056.efa4.Whatwill Switch-1 do with this data?A.switch-1 will drop the data because it dose not have an entry for that MAC addressB.switch-1 will flood the data out all of its port from which the data originatedC.switch-1 will forward the data to its default gatewayD.switch-1 will send an ARP request out all its ports except the port from which the data originatedCorrect Answer:BSection:part 1ExplanationExplanation/Reference:答案：B 没有mac地址会泛红根据下图，Switch-1需要往一台MAC地址为00b0.d056.efa4的主机发数据，Switch-1会如何处理这些数据?CCNA考试交流1000人QQ群：65330887 A.Switch-1 will drop the data because it does not have an entry for that MAC address.(Switch-1会丢弃该数据，因为它没有该MAC地址条目)B.Switch-1 will flood the data out all of its ports except the port from which the data originated.(Switch-1会泛洪该数据到所有的接口，除了该数据的源接口)C.Switch-1 will send an ARP request out all its ports except the port from which the data originated.(Switch-1会发送ARP请求到所有的接口，除了该数据的源接口)D.Switch-1 will forward the data to its default gateway.(Switch-1会往默认网关发送该数据)QUESTION 20What is the function of the command switchport trunk native vlan 999 on a switch?A.It designates VLAN 999 for untagged traffic.B.It blocks VLAN 999 traffic from passing on the trunk.C.It creates a VLAN 999 interface.D.It designates VLAN 999 as the default for all unkown tagged traffic.Correct Answer:ASection:part 1ExplanationExplanation/Reference:设置vlan999为本征vlan，交换机默认本征vlan为vlan1.此题正确答案为A.QUESTION 21Which two protocols are used by bridges and/or switches to prevent loops in a layer 2 network?(Choosetwo.)A.802.1dB.VTPC.802.1qD.STPE.SAPCorrect Answer:ADSection:part 1ExplanationExplanation/Reference:考点分析：这道题考的是生成树协议。能防止二层环路的当然是生成树协议，生成树协议有STP（802.1d）和RSTP（802.1w）。QUESTION 22Which switch would STP choose to become the root bridge in the selection process?A.32768:11-22-33-44-55-66B.32768:22-33-44-55-66-77C.32769:11-22-33-44-55-65D.32769:22-33-44-55-66-78Correct Answer:ASection:part 1ExplanationExplanation/Reference:stp选举跟桥首先比较优先级大小.然后比较mac地址大小QUESTION 23A switch is configured with all ports assigned to vlan 2 with full duplex FastEthernet to segment existingdepartmental traffic.What is the effect of adding switch ports to a new VLAN on the switch?CCNA考试交流1000人QQ群：65330887 A.More collision domains will be created.B.IP address utilization will be more efficient.C.More bandwidth will be required than was needed previously.D.An additional broadcast domain will be created.Correct Answer:DSection:part 1ExplanationExplanation/Reference:一个交换机把所有的端口以全双工的模式加到一个vlan里，把一个端口加入到一个新的vlan里会对此交换机产生什么影响？考点分析：这道题考的是vlan的概念。将一个交换的端口加入一个新vlan代表一个新的广播域产生了，因为vlan有隔离广播域的作用QUESTION 24What are three benefits of implementing vlans?(choose three)A.A more efficient use of bandwidth can be achieved allowing many physical groups to use the samenetwork infrastructureB.Broadcast storms can be mitigated by decreasing the number of broadcast domains,thus increasingtheir size.C.A higher level of network security can be reached by separating sensitive data traffic from othernetwork traffic.D.Port-based vlans increase switch-port use efficient,thanks to 802.1Q trunksE.A more efficient use of bandwidth can be achieved allowing many logical networks to use the samenetwork infrastructure.F.Broadcast storms can be mitigated by increasing the number of broadcast domains,thus reducing theirsize.G.VLANs make it easier for IT staff to configure new logical groups,because the vlans all belong to thesame broadcast domain.Correct Answer:CEFSection:part 1ExplanationExplanation/Reference:A错，不是通过物理上组合，而是逻辑上的B错，应该是增加广播域的数量C一个更高的层次网络安全可以实现,以分离的敏感数据从其他网络。正确D thanks to 802.1Q trunks不正确E正确，logical是逻辑的意思F正确G错误，是VTP的作用不是vlan的-鸿鹄论坛http:/ 25Which IEEE standard protocol is initiated as a result of successful DTP completion in a switch overFastEthernet?A.802.3adB.802.1wC.802.1QD.802.1dCorrect Answer:CSection:part 1ExplanationCCNA考试交流1000人QQ群：65330887 Explanation/Reference:动态中继协议DTP，是 VLAN 组中思科的私有协议，主要用于协商两台设备间链路上的中继过程及中继封装 802.1Q 类型。QUESTION 26Which of the following are benefits of VLANs?(Choose three.)A.They increase the size of collision domains.B.They allow logical grouping of users by function.C.They can enhance network security.D.They increase the size of broadcast domains while decreasing the number of collision domains.E.They increase the number of broadcast domains while decreasing the size of the broadcast domains.F.They simplify switch administration.Correct Answer:BCESection:part 1ExplanationExplanation/Reference:考查VLAN的特点A：增加冲突域的大小，错误B：允许逻辑划分网段，正确C：增强网络安全，正确。不同vlan不能直接通信。D：当减少冲突域时增加广播域的大小。错误E：减少广播域的大小时增加了广播域个数。正确。F:简化交换机管理。答非所问。-鸿鹄论坛http:/ 27Refer to the exhibit.A technician has installed SwithchB and needs to configure it for remote access fromthe management workstation connected SwitchA Which set of commands is required to accomplish thistask?A.SwitchB(config)#interface FastEthernet 0/1SwitchB(config)#ip address 192.168.8.252 255.255.255.0SwitchB(config)#no shutdownB.SwitchB(config)#ip default-gateway 192.168.8.254CCNA考试交流1000人QQ群：65330887 SwitchB(config)#interface vlan 1SwitchB(config)#ip address 192.168.8.252 255.255.255.0SwitchB(config)#no shutdownC.SwitchB(config)#interface vlan 1SwitchB(config)#ip address 192.168.8.252 255.255.255.0SwitchB(config)#ip default-gateway 192.168.8.254 255.255.255.0SwitchB(config)#no shutdownD.SwitchB(config)#ip default-network 192.168.8.254SwitchB(config)#interface vlan 1SwitchB(config)#ip address 192.168.8.252 255.255.255.0SwitchB(config)#no shutdownCorrect Answer:BSection:part 1ExplanationExplanation/Reference:想要远程管理交换机需要在交换机上的配置，B正确QUESTION 28In an Ethernet network,under what two scenarios can devices transmit?(Choose two.)A.when they receive a special tokenB.when there is a carrierC.when they detect no other devices are sendingD.when the medium is idleE.when the server grants accessCorrect Answer:CDSection:part 1ExplanationExplanation/Reference:在以太网网络，在什么情况下可以两种设备可以传输?考点分析：这题考的是以太网的基本概念CSMA/CD，题目问在两种情况下设备才会开始传输数据，当然是当它检测到没有其他设备在传输数据或传输介质是空闲的时才开始传输数据。-鸿鹄论坛http:/ 29Which two states are the port states when RSTP has converged?(choose two)A.blockingB.learningC.discardingD.forwardingE.listeningCorrect Answer:CDSection:part 1ExplanationExplanation/Reference:在RSTP中只有三种端口状态，Discarding、Leaning和Forwarding，汇聚之后的状态只有Discarding、Forwarding。QUESTION 30Which two commands can be used to verify a trunk link configurationt status on a given cisco switch?(choose two)CCNA考试交流1000人QQ群：65330887 A.show interfaces interfaceB.show interfaces trunkC.show interfaces switchportD.show ip interface briefE.show interfaces vlanCorrect Answer:BCSection:part 1ExplanationExplanation/Reference:查看trunk命令，show interface trunk和show interface switchport ，只能选BCQUESTION 31Which command enables RSTP on a switch?A.spanning-tree mode rapid-pvstB.spanning-tree uplinkfastC.spanning-tree backbonefastD.spanning-tree mode mstCorrect Answer:ASection:part 1ExplanationExplanation/Reference:启用RSTP的命令QUESTION 32Which of the following statements describe the network shown in the graphic?(Choose two.)A.There are two broadcast domains in the network.B.There are four broadcast domains in the network.C.There are six broadcast domains in the network.D.There are four collision domains in the network.E.There are five collision domains in the network.F.There are seven collision domains in the network.Correct Answer:AFSection:part 1CCNA考试交流1000人QQ群：65330887 ExplanationExplanation/Reference:路由器一个端口一个广播域交换机一个端口一个冲突域集线器一个冲突域。左边是集线器，右边是交换机。路由器有两个端口，所以有两个广播域。右边交换机有6个端口加上左边集线器一共7个冲突域。QUESTION 33Refer to the exhibit.All switch ports are assigned to the correct VLANs,but none of the hosts connected to SwitchA cancommunicate with hosts in the same VLAN connected to SwitchB.Based on the output shown,what is themost likely problem?A.The access link needs to be configured in multiple VLANs.B.The link between the switches is configured in the wrong VLAN.C.The link between the switches needs to be configured as a trunk.D.VTP is not configured to carry VLAN information between the switches.E.Switch IP addresses must be configured in order for traffic to be forwarded between the switchesCorrect Answer:CSection:part 1ExplanationExplanation/Reference:由图中可知，两个交换机相连接的端口都是access，应该配置成trunkQUESTION 34Refer to the exhibit.Given the output shown from this Cisco Catalyst 2950,what is the most likely reasonthat interface FastEthernet 0/10 is not the root port for VLAN 2?CCNA考试交流1000人QQ群：65330887 A.This switch has more than one interface connected to the root network segment in VLAN 2.B.This switch is running RSTP while the elected designated switch is running 802.1d Spanning Tree.C.This switch interface has a higher path cost to the root bridge than another in the topology.D.This switch has a lower bridge ID for VLAN 2 than the elected designated switch.Correct Answer:CSection:part 1ExplanationExplanation/Reference:如图，给出了Cisco交换机2950的输出代码，Fa0/10没有成为Vlan2的根端口最优可能的原因是什么？考点分析：一个端口要想成为根端口，首先比较根路径成本，越低越可能。题目问为什么没能成为根端口，原因最可能就是根路径成本比其他端口高。-鸿鹄论坛http:/ 35Why will a switch never learn a broadcast address?A.Broadcast frames are never sent to swiches.B.Broadcast addresses use an incorrect format for the switching table.C.A broadcast address will never be the source address of a frame.D.Broadcasts only use network layer addressing.E.A broadcast frame is never forwarded by a switch.Correct Answer:CSection:part 1ExplanationExplanation/Reference:QUESTION 36Refer to the exhibit.Why has this switch not been elected the root bridge for VLAN1?CCNA考试交流1000人QQ群：65330887 A.It has more than o