CCNA（200-120）803题库V2.0(2014.2.26) -选择题

Exam A QUESTION 1 Refer 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 address 0000.0c07.4320. 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: ACF Section: part 1 Explanation Explanation/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 ----------- QUESTION 2 Refer to the exhibit. Which three statements correctly describe Network Device A? (Choose three.) 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 unique IP subnet. C. With a network wide mask of 255.255.255.0, must be a Layer 2 device for the PCs to communicate with each other. D. With a network wide mask of 255.255.255.0, must be a Layer 3 device for the PCs to communicate with each other. E. With a network wide mask of 255.255.254.0, each interface does not require an IP address. Correct Answer: BDE Section: part 1 Explanation Explanation/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 3 Which layer in the OSI reference model is responsible for determining the availability of the receiving program and checking to see if enough resources exist for that communication? A. transport B. network C. presentation D. session E. application Correct Answer: E Section: part 1 Explanation Explanation/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 4 Which of the following describes the roles of devices in a WAN? (Choose three.) A. A CSU/DSU terminates a digital local loop B. A modem terminates a digital local loop C. A CSU/DSU terminates an analog local loop D. A modem terminates an analog local loop E. A router is commonly considered a DTE device F. A router is commonly considered a DCE device Correct Answer: ADE Section: part 1 Explanation Explanation/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 5 Refer to the exhibit, Host A pings interface S0/0 on router 3, what is the TTL value for that ping? A. 253 B. 252 C. 255 D. 254 Correct Answer: