配置RouterA
show ip int bri
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 2.0.0.2 YES manual up down
FastEthernet0/1 1.0.0.1 YES manual up
可以发现 Fa0/0 的状态是 down ，因为对端还没有配置完成，而 Fa0/1 的状态是 up
配置完RouterB
show ip int bri
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 2.0.0.1 YES manual up up
FastEthernet0/1 3.0.0.1 YES manual up