In my last post, tried to explain OSPF High Availability with SSO,NSF and NSR. In this post I am trying to give a snapshot how does OSPF behaves with SSO,NSF and NSR.

OSPF without SSO/NSF
1. All the OSPF neighborship are up and running. At any point of time, Router A has some issue with primary RP and it gets restarted.
2. Adjacency between router A and B will down.
3. Router B will remove the adjacency and clear the entire forwarding table for router A.
4. Router B will inform the change about router A to all its connected peers named C,D and E.
5. Now router A is up again after reboot and establish a peer relationship with router B.
6. Router B will add the routes in its routing table.
7. Router B will inform the change to its peer neighbors.