1. [单选题]What is the purpose of the Spanning Tree Protocol (STP)?
A. To prevent routing loops
B. To create a default route
C. To provide multiple gateways for hosts
D. To maintain a loop-free Layer 2 network topology
E. To enhance the functions of SNMP
2. [单选题]After connecting a PC to an available port on a switch, you find that the PC can not access any of the resources on the LAN. No other PC's connected to the switch appear to be having any issues. What is the most likely cause for this problem?
A. The router lacks a routing table entry for the new host
B. The host switch port is assigned to the incorrect VLAN
C. The host MAC address is incorrectly configured
D. A STP instance for the new host has not been initialized
E. The switch does not have the MAC address hard coded in the CAM table.
3. [单选题]FTP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
4. [多选题]属于私有IP段的是()
A. 10.0.0.0-10.255.255.255
B. 172.16.0.0-172.31.255.255
C. 202.110.100.0-202.110.100.255
D. 192.168.0.0-192.168.255.255
E. 126.0.0.0-126.255.255.255
5. [单选题]对交换机的描述，正确的是（）
A. 单广播域，单冲突域的设备
B. 单广播域，多冲突域的设备
C. 多广播域，单冲突域的设备
D. 多广播域，多冲突域的设备
6. [单选题]路由器上，命令“show int s0”的显示结果为：Serial0 is up,line protocol is down出现该结果的可能原因是（）
A. 端口处于关闭状态
B. 物理端口被烧毁
C. 两端设备协议不一致
D. 路由表中无路由
7. [单选题]OSI七层模型中，“段”是哪一层数据封装的名称（）
A. 物理层(physical layer)
B. 数据链路层(data link layer)
C. 网络层
D. 传输层
8. [多选题]Why is full-duplex Ethernet superior to its single-duplex counterpart? (Select two answer choices.)
A. It uses inexpensive hubs
B. It operates without collisions
C. It operates on switches
D. It provides faster data transfer
E. It utilizes fewer wiring pairs
9. [单选题]下列命令中，无法正确执行的是（）
A. Router(config)show run
B. Routerping 127.0.0.1
C. Router(config)hostname cisco
D. Routerreload
10. [单选题]路由器上“水平分割”的功能是：()
A. 分离端口
B. 阻止路由环路
C. 简化配置
D. 方便故障处理
