R1#sh run | b Lo
interface Loopback0
 ip address 223.1.1.1 255.255.255.0
!
interface Tunnel0
 ip address 13.13.13.1 255.255.255.0
 keepalive 10 3
 tunnel source Loopback0
 tunnel destination 222.1.1.3
!
router ospf 1
 router-id 0.0.0.1
 log-adjacency-changes
 network 13.13.13.1 0.0.0.0 area 0
 network 17.57.100.1 0.0.0.0 area 0
!


R3#sh run | b Lo
interface Loopback0
 ip address 222.1.1.3 255.255.255.0
!
interface Tunnel0
 ip address 13.13.13.3 255.255.255.0
 keepalive 10 3
 tunnel source Loopback0
 tunnel destination 223.1.1.1
!
router ospf 1
 router-id 0.0.0.3
 log-adjacency-changes
 network 13.13.13.3 0.0.0.0 area 0
 network 17.80.1.1 0.0.0.0 area 0