OSPF basic topology and config

Our topology here is point to point with OSPF AS 24 and all the router belongs to Area 0 with class C IP.

 

On Point – Point connection topology the OSPF adjacency state is Full, There is no DR or BDR.
sho ip ospf nei will show routers that form adjacency

 

Here on show ip ospf database command as you see the sequence number is the same , this sequence number  is a 32 bit that start from 0x8000001 to 0x7FFFFFF , The larger the number  the recent the LSA  is. To ensure an accurate database, OSPF floods each LSA every 30 min and it called LSRefresh   with the max of 60 min (it shows in sec in the router).