1. [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
2. [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
3. [单选题]IP地址为：192.168.50.70，掩码为：255.255.255.248，则该IP地址所在子网的广播地址为（）
A. 192.168.50.32
B. 192.168.80.64
C. 192.168.50.96
D. 192.168.50.71
4. [多选题]With regard to Ethernet media access methods, which of the following are true?(Choose all that apply.)
A. A device waits for an electronic signal before transmitting.
B. A device listens and waits until the media is not busy before transmitting.
C. All devices on an Ethernet segment see data that passes on the network medium.
D. Only the sender and the receiver devices see data that passes on the network medium.
E. Ethernet networks allow you to configured devises with higher transmission priority.
5. [单选题]对路由器的描述，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
