思科認(rèn)證考試試題庫(kù)(編輯修改稿)

　

【文章內(nèi)容簡(jiǎn)介】 IP address is incorrect. C. The subnet mask is incorrect. D. The serial line encapsulations are inpatible. E. The maximum transmission unit (MTU) size is too large. F. The bandwidth setting is inpatible with the connected interface. Answer: B解釋一下：很明顯的錯(cuò)誤啊，兩臺(tái)路由器的串行接口的地址配置錯(cuò)誤，不是在相同的網(wǎng)段，從而導(dǎo)致了不能通訊。29. Which two values are used by Spanning Tree Protocol to elect a root bridge? (Choose two.) A. amount of RAM B. bridge priority C. IOS version D. IP address E. MAC address F. speed of the links Answer: BE解釋一下：生成樹(shù)的選舉的問(wèn)題，根橋的選舉是通過(guò)比較ＢＩＤ的，而ＢＩＤ由橋優(yōu)先級(jí)和ＭＡＣ地址組成的．所以在選根橋的時(shí)候需要比較的是橋優(yōu)先級(jí)和ＭＡＣ　address。30. Refer to the exhibit. Which switch provides the spanningtree designated port role for the network segment that services the printers? A. Switch1 B. Switch2 C. Switch3 D. Switch4 Answer: C解釋一下：這是個(gè)關(guān)于生成樹(shù)選舉的問(wèn)題，我們首先需要找到根橋，而根橋的選舉是通過(guò)比較橋ID的,而且是越小越優(yōu)先，橋ID的組成為橋優(yōu)先級(jí)和MAC地址。所以我們通過(guò)上圖可以找到根橋?yàn)閟witch 1。然后在非根橋上選出根端口，通過(guò)比較到根橋的花費(fèi)來(lái)選舉的，花費(fèi)最小的就是根端口。因?yàn)樯蠄D中沒(méi)有表示出鏈路的帶寬，所以無(wú)法比較他們的花費(fèi)。下一步我們來(lái)選舉指派端口。每條鏈路都需要有一個(gè)DP，先是比較花費(fèi)，如果花費(fèi)相同則比較BID（橋優(yōu)先級(jí)），仍是越小越優(yōu)先，根據(jù)上圖的表識(shí)，我們可以找到每條鏈路上的DP，而連Printers的鏈路上的DP就為Switch 3，因?yàn)樗懈〉腗AC地址。32. Refer to the exhibit. Why would the network administrator configure RA in this manner?A. to give students access to the Internet B. to prevent students from accessing the mand prompt of RA C. to prevent administrators from accessing the console of RA D. to give administrators access to the Internet E. to prevent students from accessing the Internet F. to prevent students from accessing the Admin network Answer: B解釋一下：在這兒，將ＡＣＬ應(yīng)用到ＶＴＹ線路下，而且是ＩＮ的方向，表示凡是被我的ＡＣＬ允許的才能telnet到我．在ＲＡ上配置的是permit any 允許Ａdmin的網(wǎng)段中的用戶可以telnet到他，所以Ｓtudent的網(wǎng)段中的用戶是被拒絕的．33. In order to allow the establishment of a Telnet session with a router, which set of mands must be configured? A. router(config) line console 0 router(configline) enable password cisco B. router(config) line console 0 router(configline) enable secret cisco router(configline) loginC. router(config) line console 0 router(configline) password cisco router(configline) login D. router(config) line vty 0 router(configline) enable password cisco E. router(config) line vty 0 router(configline) enable secret cisco router(configline) login F. router(config) line vty 0 router(configline) password cisco router(configline) login Answer: F解釋一下：telnet是一個(gè)應(yīng)用層的應(yīng)用，他使用的是vty線路，而且在默認(rèn)的情況下，是需要訪問(wèn)的線路下設(shè)有密碼的。而在VTY線路下設(shè)置密碼的命令為 passwork string ,而VTY線路下的另一個(gè)命令login則是默認(rèn)的，可寫(xiě)也可不寫(xiě)。如果想Telnet時(shí)在VTY線路下不設(shè)置密碼也可以訪問(wèn)這個(gè)線路，可以在該VTY線路下輸入命令 no login。34. Refer to the exhibit. The two exhibited devices are the only Cisco devices on the network. The serial network between the two devices has a mask of . Given the output that is shown, what three statements are true of these devices? (Choose three.) A. The Manchester serial address is . B. The Manchester serial address is . C. The London router is a Cisco 2610. D. The Manchester router is a Cisco 2610. E. The CDP information was received on port Serial0/0 of the Manchester router. F. The CDP information was sent by port Serial0/0 of the London router. Answer: ACE解釋一下：ＣＤＰ是ＣＩＳＣＯ私有的一個(gè)二層的協(xié)議，但是他卻可以發(fā)現(xiàn)三層的ＩＰ信息的．通過(guò)ＣＤＰ可以發(fā)現(xiàn)的鄰居的信息有：設(shè)備的名稱，ＩＰ地址，端口，能力，平臺(tái)，對(duì)端的holddown time．在上圖的show cdp entry *命令的顯示可以看到的信息有：設(shè)備名稱：Ｌondon；ＩＰ地址：；平臺(tái)：cisco 2610；能力：Router；端口：s0/１；holdtime：１２５Ｓ．Ｍanchesteter收到這個(gè)ＣＤＰ信息的接口為S0/0．綜合一下，這個(gè)題目的答案就出來(lái)了．35. A network administrator has configured two switches, named London and Madrid, to use VTP. However, the switches are not sharing VTP messages. Given the mand output shown in the graphic, why are these switches not sharing VTP messages? A. The VTP version is not correctly configured. B. The VTP operating mode is not correctly configured. C. The VTP domain name is not correctly configured. D. VTP pruning mode is disabled. E. VTP V2 mode is disabled. F. VTP traps generation is disabled. Answer: C解釋一下：交換機(jī)間不能共享VTP的信息，我們就需要檢查VTP的狀態(tài)，首先需要檢查的是VTP的域名，只有同一個(gè)域中的才可能相互學(xué)習(xí)，再來(lái)檢查VTP的模式，必須有一個(gè)server模式才能有VTP學(xué)習(xí)的過(guò)程的，默認(rèn)的情況下VTP的模式為Server的。然后我們檢查圖題目給出的信息，可以看到兩臺(tái)交換機(jī)的VTP domain是不一致的，所以這個(gè)就是問(wèn)題的所在了。36. Host 1 is trying to municate with Host 2. The e0 interface on Router C is down. Which of the following are true? (Choose two.) A. Router C will use ICMP to inform Host 1 that Host 2 cannot be reached. B. Router C will use ICMP to inform Router B that Host 2 cannot be reached. C. Router C will use ICMP to inform Host 1, Router A, and Router B that Host 2 cannot be reached. D. Router C will send a Destination Unreachable message type. E. Router C will send a Router Selection message type. F. Router C will send a Source Quench message type. Answer: AD解釋一下：連Host 2的接口E0/0 down了，那么最直接的反映就發(fā)生在路由器C上，C的路由表中的這個(gè)條目就消失了，因此當(dāng)Host 1 想要跟Host 2建立連接的時(shí)候，Router C就發(fā)送一個(gè)目的網(wǎng)段不可達(dá)的消息；如果是使用ping命令，那么Router C就使用ICMP 的包文告訴Host 1，Host 2是不可打的。37. Refer to the exhibit. Assuming that the router is configured with the default settings, what type of router interface is this? A. Ethernet B. FastEthernet C. Gigabit Ethernet D. asynchronous serial E. synchronous serial Answer: B解釋一下：這個(gè)題是需要根據(jù)圖中提供的信息來(lái)判斷接口的類型。可以看到接口的MAC地址，表示這個(gè)接口肯定不是串行接口，所以可以排除D和E的選項(xiàng)。看帶寬BW 100000 Kbit,表示的是100M的帶寬，所以這是個(gè)Fast Ethernet接口。38. On pointtopoint networks, OSPF hello packets are addressed to which address? A. B. C. D. E. F. Answer: E解釋一下：。大家在做OSPF實(shí)驗(yàn)的時(shí)候，用debug命令是可以看到這兩個(gè)個(gè)地址的。 troubleshooting a connectivity problem, a network administrator notices that a port status LED on a Cisco Catalyst series switch is alternating green and amber. Which condition could this indicate? A. The port is experiencing errors. B. The port is administratively disabled. C. The port is blocked by spanning tree. D. The port has an active link with normal traffic activity. Answer: A解釋一下：CISCO交換機(jī)的端口狀態(tài)指示燈是閃爍的綠色和淺黃色，表示端口有操作的問(wèn)題——也許是過(guò)量的錯(cuò)誤或連接的問(wèn)題。40. Refer to the exhibit. The network shown in the exhibit is running the RIPv2 routing protocol. The network has converged, and the routers in this network are functioning