[quagga-users 9947] Re: Multiple OSPF router instances?

Alexis Rosen quagga-users at alexis.users.panix.com
Sun Sep 28 06:16:57 IST 2008

On Sep 27, 2008, at 1:15 PM, paul at clubi.ie wrote:
> On Sat, 27 Sep 2008, Alexis Rosen wrote:
>> Simple... At least on Ciscos there's no way to filter OSPF routes  
>> you hear from a neighbor. You can prevent them from getting into  
>> your FIB, but the LSAs stay in the OSPF database and are propogated  
>> to other routers. Contrast this with RIP2, or BGP, where you can  
>> apply route-maps, prefix-lists, etc. to incoming route  
>> announcements. This can be useful for many reasons.
> Aha..
> Well, first off, google for "why can't i filter ospf" ("I'm feeling  
> lucky" should work). Assuming you've read that, there are  
> alternatives:

Yeah, I understand the difference between D-V and LS protocols. I was  
trying to break it down for anyone who wasn't.

> a) You can filter between OSPF areas

This could be made to work. At the time we set things up, running  
multiple OSPFs was a dramatically cleaner solution.

> b) You can filter what goes into the zebra FIB with route-maps, I
>   think.

I'd be surprised if you couldn't... but that doesn't help us.

Anyway, we will probably use a mixture of inter-area filtering and  
other protocols.


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