[c-nsp] Changing OSPF from single area to multiple areas

[Oliver Boehmer (oboehmer)]

Primoz Jeroncic <> wrote on Monday, March 19, 2007 11:16 AM:

> Hi everyone
> [...]
> Since network is pretty much star design with backbone in middle and
> parts of network going out from center, I was thinking to start
> changing this from middle. Now my question is, is it possible to
> change it in few steps?
> I was thinking to change backbone (center of network) to area 0, and
> for first few days leave other parts of network intact, that means
> on area 100. Would this work or would there be problem if networks on
> side of backbone would all be in same area? Basically network after
> initial change would look like this (just that there would be more
> then just Network A and B on outside perimeter):
> 
> Network A (area 100) --- Backbone (area 0) --- Network B (area 100)
> 
> Of course Network A and Network B should be visible for each other.
> 
> So would something like this work?

yes, nothing wrong with using the same non-backbone area number on both
(or more) sides of the core.. 

But I'd recommend not to over-do the segmentation, there's usually
nothing wrong with an area of 100+ nodes (even several hundreds) with
today's hardware.. So having core and distribution in the backbone area
and using areas out into the access layer is usually a practical
approach.. all depends on how your network looks like.

	oli