OSPF Design

[Mokhalil82]

Hi 

This is a design question for OSPF, if I have a triangular network model with the production site and 2 datacentres, currently running static routing. I now want to implement dynamic routing in the form of OSPF. Is it a good idea to use area 0 for the production site and both data centres or is it better for production to be in area 0 and DC1 in area 1 and DC2 in area 2

Thanks

[Reza Sharifi · Accepted solution]

Hi,

If you don't have lots of routes and routers and no need for summarization and OSPF database reduction, all routers in area 0 should be sufficient.

HTH

[Mokhalil82]

Thanks for that guys, i may go for a single area in that case as there aren't may routers

[Joseph W. Doherty]

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Posting

BTW, an old (and rough) rule-of-thumb, was about 50 routers per OSPF area.  But again, that's not a hard fast rule.

Much depends on the control plane capacity of your L3 devices, how many links are in the topology and their stability.

[Joseph W. Doherty · Accepted solution]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

As Reza noted, if your overall topology isn't that large, one area should suffice for everything.  Oh, and BTW, if you use a single area, it doesn't have to be area zero.

If you did want to use areas, besides each DC being in its own area, you would probably want your production site to also be in its own area, but not area zero.  Area zero should be used as a logical core to tie together your other areas.