Upper ROUTER

interface serial0
ip address 192.168.7.2 255.255.255.0
no ip directed-broadcast
no ip route-cache
no ip mroute-cache
no fair-queue
!
interface serial1
ip address 192.168.7.3 255.255.255.0
no ip directed-broadcast
no ip route-cache
no ip mroute-cache
!


Lower ROUTER

interface serial0
ip address 192.168.7.4 255.255.255.0
no ip directed-broadcast
no ip mroute-cache
no fair-queue
!
interface serial1
ip address 192.168.7.1 255.255.255.0
no ip directed-broadcast
!