en
conf t
router ospf 1
auto-cost reference-bandwidth 1000
exit
!! copy paste above commands in all the routers
--------------------------------------------------------------------------------------
From 1.2 pc -> ping 192.168.8.2
In R3 -> 'do write'  to save and poweroff
------------------------------------------------------------------------------
!!! R1 
int g0/1
ip ospf hello-interval 1
exit
---------------------------------------------------------------------
!!! R3
int g0/0
ip ospf hello-interval 1
exit
do show ip ospf neighbor
---------------------------------------------------------------------------
From 1.2 pc -> ping 192.168.8.2
In R3 -> 'do write'  to save and poweroff