1. [单选题]哪个命令可以成功测试网络：()
A. Router>ping192.5.5.0
B. Routerping192.5.5.30
C. Router>ping192.5.5.256
D. Routerping192.5.5.255
2. [单选题]At which layer of the OSI model does the protocol that provides the information displayed by the "show cdp neighbors" command operate?
A. Transport
B. Physical
C. Application
D. Data link
E. Network
3. [单选题]An administrator issues the show ip interface s0/0 command and the output displays that interface Serial0/0 is up, line protocol is up.What does "line protocol is up" specifically indicate about the interface?
A. The cable is attached properly.
B. CDP has discovered the connected device.
C. Keepalives are being received on the interface.
D. A carrier detect signal has been received from the connected device.
E. IP is correctly configured on the interface.
4. [单选题]配置路由器特权用户“加密密码”的命令是：()
A. password
B. enable password
C. enable secret
D. passwd
5. [单选题]While troubleshooting a connectivity problem on the network, you issue the ping command from your PC command prompt, but the output shows "request times out."At which OSI layer is this problem associated with?
A. The data link layer
B. The application layer
C. The access layer
D. The session layer
E. The network layer
