ccna考试题库.docx

1、ccna考试题库ccna考试题库(总34页)QUESTION 37What are two characteristics of RIPv2 (Choose two.)A. classful routing protocolB. variable-length subnet masksC. broadcast addressingD. manual route summarizationE. uses SPF algorithm to compute pathAnswer: BDExplanation/Reference:A：有类路由协议，错误B：可变长度子网掩码，正确C：采用广播地址更新，错

2、误D：手动路由汇总，正确E:使用spf算法计算路径，错误。QUESTION 38Which two Ethernet fiber-optic modes support distances of greater than 550 meters?A.1000BASE-CXB. 100BASE-FXC. 1000BASE-LXD. 1000BASE-SXE. 1000BASE-ZXAnswer: CEExplanation/Reference:A：最长距离25米B：最长距离100米C：最长距离3000米D：最长距离550米E：最长距离70千米QUESTION 39What two things w

3、ill a router do when running a distance vector routing protocol (Choose two.)A. Send periodic updates regardless of topology changes.B. Send entire routing table to all routers in the routing domain.C. Use the shortest-path algorithm to the determine best path.D. Update the routing table based on up

4、dates from their neighbors.E. Maintain the topology of the entire network in its database.Answer: ADExplanation/Reference:考点：考查距离矢量路由协议特性A：周期性更新，正确B：发送整个路由表到整个路由域，错误，只发送给邻居C：使用SPF算法，错误D：依靠邻居发送更新来更新路由表，正确E：在数据库中维护整个网络的拓扑。错误Which command shows if an access list is assigned to an interface?A. show ip i

5、nterface interface access-listsB. show ip access-lists interface interfaceC. show ip interface interfaceD. show ip access-lists interfaceAnswer: CExplanation/Reference:QUESTION 42Refer to the exhibit. Which rule does the DHCP server use when there is an IP address conflictA. The address is removed f

6、rom the pool until the conflict is resolved.B. The address remains in the pool until the conflict is resolved.C. Only the IP detected by Gratuitous ARP is removed from the pool.D. Only the IP detected by Ping is removed from the pool.E. The IP will be shown, even after the conflict is resolved.Answe

7、r: AExplanation/Reference:show ip dhcp conflict命令可以查看哪些ip地址在使用上有冲突。有冲突的地址不再分配出去。A：地址被删除直到冲突解决，正确B:地址保留直到冲突解决，错误C/D：答案片面。E：当冲突解决后，地址会被显示。错误。QUESTION 44Refer to the exhibit. If number 2 is selected from the setup script, what happens when the user runs setupfrom a privileged prompt?A. Setup is additiv

8、e and any changes will be added to the config script.B. Setup effectively starts the configuration over as if the router was booted for the first time.C. Setup will not run if an enable secret password exists on the router.D. Setup will not run, because it is only viable when no configuration exists

9、 on the router.Answer: AExplanation/Reference:0不保存进入IOS命令配置模式1不保存返回设置模式2保存退出A：设置和改动被保存到配置脚本B：为有效地重新开始配置，如果路由器是第一次启动的配置。C：如果配置了密码，设置不会运行D：设置不可用，因为它只能在没有配置存在时才有效QUESTION 49Which two statements describe the Cisco implementation of VLANs (Choose two.)A. VLAN 1 is the default Ethernet VLAN.B. CDP adverti

10、sements are only sent on VLAN 1002.C. By default, the management VLAN is VLAN 1005.D. By default, the switch IP address is in VLAN 1005.E. VLAN 1002 through 1005 are automatically created and cannot be deleted.Answer: AEExplanation/Reference:考点：考查vlan知识点。A：缺省都存在vlan1，端口都属于vlan1，正确B：CDP信息只发送到vlan1002

11、，错误，vlan1002是fddi网络的vlan号。C：缺省情况交换机IP配置在vlan1005，错误，vlan1005trnet网络的vlan号。缺省在vlan1里面。D：vlan1002-1005自动生成并不能被删除，正确，他们都是被保留的特殊vlan。QUESTION 56 没有理解什么意思Refer to the exhibit. What does the (*) represent in the output?A. Packet is destined for a local interface to the router.B. Packet was translated, but

12、 no response was received from the distant device.C. Packet was not translated, because no additional ports are available.D. Packet was translated and fast switched to the destination.Answer: DExplanation/Reference:由图中提示信息可以看出，源为已经有个一个转换，所以后续的数据包快速转发。What are three advantages of VLANs (Choose three.

13、)A. VLANs establish broadcast domains in switched networks.B. VLANs utilize packet filtering to enhance network security.C. VLANs provide a method of conserving IP addresses in large networks.D. VLANs provide a low-latency internetworking alternative to routed networks.E. VLANs allow access to netwo

14、rk services based on department, not physical location.F. VLANs can greatly simplify adding, moving, or changing hosts on the network.Answer: AEFExplanation/Reference:A：VLAN在交换网络中建立广播域，正确B：利用VLAN的数据包过滤，增强网络的安全性。错误，没有这个特性。C：提供了在大型网络中的保护IP地址的方法。错误D：提供低延迟互联网络替代路由网络。错误E：vlan允许基于逻辑划分的网络访问，不是物理位置。正确。F：VLA

15、N可以大大简化添加，移动或更改网络上的主机。正确。QUESTION 61An administrator would like to configure a switch over a virtual terminal connection from locations outsideof the local LAN. Which of the following are required in order for the switch to be configured from a remotelocation (Choose two.)A. The switch must be confi

16、gured with an IP address, subnet mask, and default gateway.B. The switch must be connected to a router over a VLAN trunk.C. The switch must be reachable through a port connected to its management VLAN.D. The switch console port must be connected to the Ethernet LAN.E. The switch management VLAN must

17、 be created and have a membership of at least one switch port.F. The switch must be fully configured as an SNMP agent.Answer: ACExplanation/Reference:要想远程管理VLAN，1、交换机配置IP，2、路由可达QUESTION 65Which router IOS commands can be used to troubleshoot LAN connectivity problems (Choose three.)A. pingB. tracert

18、C. ipconfigD. show ip routeE. winipcfgF. show interfacesAnswer: ADFExplanation/Reference:A：测试连通性D：查看是否有路由F：查看接口是否可用QUESTION 64Which 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.允许用户从逻辑上进行分组C.

19、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.Answer: BCEExplanation/Referenc

20、e: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。QUESTION 71Which characteristics are representative of a link-state routing protocol (Choose three.)A. provides common view of entire topologyB. exchanges routing tables with neigh

21、borsC. calculates shortest pathD. utilizes event-triggered updatesE. utilizes frequent periodic updatesAnswer: ACDExplanation/Reference:链路状态路由协议有协议特点？A:提供查看拓扑的命令，正确。show ip ospf databaseB：邻居之间交换路由信息，错误。交换LSAC：计算最短路径，正确。D：利用触发更新，正确E：利用周期更新，错误。QUESTION 73Use the output from the router shown in the gra

22、phic above to determine which of the following are correct.(Choose two.)A. Router John uses a link-state routing protocol.B. Router John will receive routing updates on the Serial0/0 interface.C. Router John will receive routing updates on the Serial0/1 interface.D. Router John will send routing upd

23、ates out the Serial0/0 interface.E. Router John will send routing updates out the FastEthernet0/0 interface.F. Router John will send routing updates out the Serial0/1 interface.Answer: BDExplanation/Reference:由图中几处画红线的地方可知只有s0/0发送和接受路由信息。QUESTION 74 2的次方问题A national retail chain needs to design an I

24、P addressing scheme to support a nationwide network. Thecompany needs a minimum of 300 sub-networks and a maximum of 50 host addresses per subnet.Working with only one Class B address, which of the following subnet masks will support an appropriateaddressing scheme (Choose two.)A. B. C. D. E. F. Ans

25、wer: BEExplanation/Reference:需要至少300个子网，每个子网至少50台主机。使用一个B类地址来划分。A：最多有256个子网，错误C：只有64个子网D：每个子网只有30个可用IPF：只有32个子网QUESTION 79What information does a router running a link-state protocol use to build and maintain its topologicaldatabase (Choose two.)A. hello packetsB. SAP messages sent by other routersC

26、. LSAs from other routersD. beacons 信息received on point-to-point linksE. routing tables received from other link-state routersF. TTL packets from designated routersAnswer: ACExplanation/Reference:链路状态路由协议如何维护拓扑数据库？A：hello包用于维护邻居关系，正确。B：错误，没有这个概念。C：通过其他路由器的LSA，正确。D：从点到点链路接收，错误。答案片面E：从其他路由器接收路由表，错误。相互

27、间不直接发送路由表。F：从DR接受TTL包，错误，答非所问。QUESTION 80Which statements describe the routing protocol OSPF (Choose three.)A. It supports VLSM.B. It is used to route between autonomous systems.C. It confines network instability to one area of the network.D. It increases routing overhead on the network.E. It allows

28、 extensive control of routing updates.F. It is simpler to configure than RIP v2.Answer: ACEExplanation/Reference:A：支持VLSM，正确B：在AS之间使用，错误。在AS内部使用C：限制了不稳定网络的范围，正确。通过划分区域实现。D：增加了网络的开销，错误。E：允许路由更新控制，正确。F：比RIPv2更容易配置，错误，答非所问。Which of the following are types of flow control (Choose three.)A. bufferingB. c

29、ut-throughC. windowingD. congestion avoidanceE. load balancingAnswer: ACDExplanation/Reference:流控制有哪些？A：缓存B：直通C：窗口机制D：拥塞避免E：负载均衡。What can be determined from the line of show ip route output shown in the exhibit (Choose two.) 注意R =rip 管理距离修改Rout ripDistance 10A. The next routing update can be expecte

30、d in 35 seconds.B. The IP address is configured on S0/1.C. The IP address is configured on S0/1.D. This route is using the default administrative distance.E. The network is two hops away from this router.Answer: DEExplanation/Reference:考点：考查RIP的路由条目。通过RIP学习到一条到达的路由，下一跳是，出接口是s/1。A：错误。rip更新周期为30s，正常计时

31、器不会超过30B：错误，这个ip是对端接口ipC：错误。s0/1的ip无法得知D：正确，rip缺省的管理距离是120E：正确。QUESTION 93Refer to the exhibit. From RouterA, a network administrator is able to ping the serial interface of RouterBbut unable to ping any of the subnets attached to RouterB. Based on the partial outputs in the exhibit, whatcould be the problem?A. EIGRP does not support VLSM.B. The EIGRP network statements are incorrectly configur