核心配置
R1
ip route-static 3.3.3.3 255.255.255.255 GigabitEthernet0/0/0 10.1.1.2
ip route-static 3.3.3.3 255.255.255.255 GigabitEthernet0/0/1 20.1.1.2
ip route-static 30.1.1.0 255.255.255.0 GigabitEthernet0/0/0 10.1.1.2
ip route-static 30.1.1.0 255.255.255.0 GigabitEthernet0/0/1 20.1.1.2
R2
ip route-static 1.1.1.1 255.255.255.255 GigabitEthernet0/0/0 10.1.1.1
ip route-static 1.1.1.1 255.255.255.255 GigabitEthernet0/0/1 20.1.1.1
ip route-static 3.3.3.3 255.255.255.255 GigabitEthernet0/0/2 30.1.1.3
R3
ip route-static 1.1.1.1 255.255.255.255 GigabitEthernet0/0/0 30.1.1.2
ip route-static 10.1.1.0 255.255.255.0 GigabitEthernet0/0/0 30.1.1.2
ip route-static 20.1.1.0 255.255.255.0 GigabitEthernet0/0/0 30.1.1.2
原理
R1
R3
R2