Please help me clear this question: Where do we can issue the ospf "summary address" command. At first I think this command can only be issued on ASBR router, but then I came across a lab which told me that this command can be run in regular router, I actually be able to do it. I would be much appreciate if anyone could explain for me this case.
in ospf you can summarize routes int ASBR or ABR routers when send routes into area 0.
on ASBR you can use summary address [prefix] [mask] command.
you can add other paramether: not-advertise
on ABR you can use area [x] range [prefix] [mask] command.
you can add other paramethers advertise, not-advertise and cost.
If you use this aggregation methods your router will suppress all of the specific routes which are included into summary.