Assuming I have a fairly small network internally, but I have 4 routers each connected out to a different network. The routers are all sat next to each other connected via a switch. Each router uses BGP to speak to the outside networks. There is an iBGP mesh for each router to exchange the routes internally it knows about from each external network.
The usual setup is to use OSPF to distribute the connected routes, as the routes via iBGP will still have the next hop set to their original value.
What is the advantage of using OSPF in this scenario versus simply using 'set nexthop self' on the routes?
Best Answer
OSPF is way faster reacting to topology changes than BGP, so it's a basis for loop/blackhole avoidance.