配置命令：
AR1：
SYS
INT G0/0/0
IP ADD 172.16.3.1 24
Q
INT G0/0/1
IP ADD 172.16.2.1 24
Q
INT G0/0/2
IP ADD 172.16.1.1 24
Q
IP route-static 172.16.4.0 24 172.16.2.2
IP route-static 172.16.4.0 24 172.16.3.2
q
rip
version 2
network 172.16.0.0
q
ospf
area 0
network 172.16.1.0 0.0.0.255
network 172.16.2.0 0.0.0.255
network 172.16.3.0 0.0.0.255
AR2：
SYS
INT G0/0/0
IP ADD 172.16.3.2 24
Q
INT G0/0/2
IP ADD 172.16.4.1 24
Q
INT G0/0/1
IP ADD 172.16.2.2 24
Q
IP route-static 172.16.1.0 24 172.16.2.1
IP route-static 172.16.1.0 24 172.16.3.1
q
rip
version 2
network 172.16.0.0
q
ospf
area 0
network 172.16.1.0 0.0.0.255
network 172.16.2.0 0.0.0.255
network 172.16.3.0 0.0.0.255