ispf command under ospf process

happy420golucky

Hello everybody, I have started my studies towards the CCIP/CCIE path. While I was lurking around, I learned of the "ISPF" command and what it does. A wondered if anybody can tell me if this command is best used for a stub network and issue that command on the ABR router connected to the stub? Should you put that command on both routers, one router etc...
I searched the site, and have googled a few times, but just wanted to cut to the chase. Any links or input is greatly appreciated.

EdTheLad

This command is locally significant, i would enable it on all routes in my network.
Two cases, intra area topology change, inter area topology change.

So if a topology change occurs intra area, the router that experienced the change will perform a recalc, and build a new SPT. LSA's are then flooded, other routers in the area that have ispf configured can make a simple modification to the SPT without performing a recalc.

Inter area topology change, type 3,4,5,7 lsa's are received and the SPT is updated without a recalc needed.

The question is what negative impacts can this feature have on the network, none that i can see.It's adding more intelligence to the router, i suppose it uses more ram, that's the only concern if you are running legacy equipment.