1. [单选题]How many usable IP addresses can you get from a conventional Class C address?
A. 128
B. 192
C. 254
D. 256
E. 510
2. [单选题]下列哪个network命令会告知此路由器开始使用IP地址为10.1.1.1、10.1.100.1和10.1.120.1的接口上的OSPF()
A. network 10.0.0.0 255.0.0.0 area 0
B. network 10.0.0.0 0.255.255.255 area 0
C. network 10.0.0.1 0.0.0.255 area 0
D. network 10.0.0.1 0.0.255.255 area 0
3. [单选题]默认情况下,RIP定期发送路由更新的时间是()
A. 15S
B. 30S
C. 60S
D. 90S