Router(config)#hostname DaNang
DaNang(config)#int s0
DaNang(config-if)#ip address 11.0.0.2 255.255.255.252
DaNang(config-if)#no shut
%LINK-3-UPDOWN: Interface Serial0, changed state to up
DaNang(config-if)#int s1
DaNang(config-if)#ip address 12.0.0.1 255.255.255.252
DaNang(config-if)#no shut
%LINK-3-UPDOWN: Interface Serial1, changed state to up
DaNang(config-if)#exit
%LINK-3-UPDOWN: Interface Serial1, changed state to down
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed state to down
%LINK-3-UPDOWN: Interface Serial1, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed state to up
DaNang(config)#router ospf 12
DaNang(config-router)#network 12.0.0.0 0.0.0.3 area 0
DaNang(config-router)#network 11.0.0.0 0.0.0.3 area 0
DaNang(config-router)#exit
DaNang(config)#exit
DaNang#show ip ospf database 

       OSPF Router with ID (12.0.0.1) (Process ID 12)

         Router Link States (Area 0) 

Link ID         ADV Router      Age         Seq#       Checksum Link count
                     0   0x80000001    0x7794 
11.0.0.2        11.0.0.2           0   0x80000007    0x7830 
12.0.0.1        11.0.0.2           0   0x80000004    0x6347 

DaNang#show ip ospf database 

       OSPF Router with ID (12.0.0.1) (Process ID 12)

         Router Link States (Area 0) 

Link ID         ADV Router      Age         Seq#       Checksum Link count
                     0   0x80000008    0x6598 
11.0.0.2        11.0.0.2           0   0x80000004    0x9672 
12.0.0.1        11.0.0.2           0   0x80000001    0x4699