1. [单选题]TELNET工作在OSI哪一层（）
A. 会话层(session layer)
B. 表示层
C. 传输层
D. 应用层
2. [多选题]The Ezonexam network administrator needs to determine what LAN devices to install on the Ezonexam network. What are two advantages of using Layer 2 Ethernet switches over hubs? (Choose two)
A. Allowing simultaneous frame. transmissions
B. Increasing the size of broadcast domains
C. Increasing the maximum length of UTP cabling between devices
D. Filtering frames based on MAC addresses
E. Decreasing the number of collision domains
3. [单选题]路由器上，清空路由表的命令是（）
A. clear ip
B. delete ip route
C. delete route
D. clearip route*
4. [单选题]路由器下，由一般用户模式进入特权用户模式的命令是：（）
A. enable
B. config
C. interface
D. router
5. [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.
