Number of OSPF areas?

Unanswered Question
Jan 2nd, 2008

Happy New Year to all who may read my post :)

We have multiple L2 VLAN's on our 6509's and I am tasked to setup dynamic OSPF routing.

Which is better; cpu, memory and effective configuration.

1) create a OSPF area for each VLAN

2) create 1 OSPF area with all the VLAN's in it

off course our core are will be which will span to all inter office router's connection points.

any advise/reading material on the subject would be greatly appreciated.

I have this problem too.
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Jon Marshall Wed, 01/02/2008 - 09:57


It is highly unlikely that you would want a separate area per vlan on your 6500 switch. That would make your configuration very complex.

If you have multiple offices one common setup is to have HQ as area 0 and your remote sites in different areas but without knowing more about your topology it is difficult to be more specific about what is good for you.

Attached is a link to Cisco white paper on OSFP design, have a read and them come back if you require further assistance.



dajekels1 Wed, 01/02/2008 - 10:11


Thank you for the quick response, I have read this doc a few times and all the example configs in this guide only has 1 network assigned to an area.

Short of a lab; I just needed some clarification on the approach which I had stuck in my head :-)



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