sys
sysname r1
int e0/0/0
ip add 192.168.1.1 24
int e0/0/1
ip add 192.168.12.1 24
ospf 1 rou 1.1.1.1
a 0
netw 192.168.1.1 0.0.0.0 
netw 192.168.12.1 0.0.0.0

sys
sysname r2
int e0/0/0
ip add 192.168.12.2 24
int e0/0/1
ip add 192.168.23.1 24
ospf 1 rou 2.2.2.2
a 0
netw 192.168.12.2 0.0.0.0 
netw 192.168.23.1 0.0.0.0

sys
sysname r3
int e0/0/0
ip add 192.168.23.2 24
int e0/0/1
ip add 192.168.2.1 24
ospf 1 rou 3.3.3.3
a 0
netw 192.168.23.2 0.0.0.0 
netw 192.168.2.1 0.0.0.0