1. [单选题]RIP路由协议认为“网络不可到达”的跳数是：()
A. 8
B. 16
C. 24
D. 100
2. [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*
3. [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
