If you’re looking for a ridiculously easy way to make your OSPF process more efficient, you’ve come to the right place. According to Cisco, many of the CPU cycles spent on evaluating Dijkstra’s algorithm are unnecessary. You can save your router a lot of work by performing incremental SPF calculations in many cases rather than full SPF calculations.
How do you do it? It’s easy:
R0(config)# router ospf 1
R0(config-router)# ispf
R0(config-router)#
That’s it! Best of all, it doesn’t cause the adjacency to drop and it doesn’t need to be enabled on all routers!