Re: OSPF default route multiple processes

Here's a small drawing.... Hope this helps!

https://www.dropbox.com/s/bretv9kp5k66ggp/ospf%20multiple%20process.jpg

On Fri, Jul 26, 2013 at 6:50 PM, Marc La Porte <marc.a.laporte_at_gmail.com>wrote:

> Hi all,
>
> I have a situation within our data center where I have two OSPF processes
> (each with only one area) and a single point of contact (border router)
> between the two. I have OSPF process 51, area 51; and I have OSPF process 1
> area 0.
>
> Area 51 has a single Internet connection and the point where I do a
> default-information originate (type 2; default metric)
> Area 0 has two Internet connections and both do a default-information
> originate (type 1; different metrics)
> On the border router, there is mutual redistribution of all routes except
> the default route which is filtered out in both directions (so each area
> has it's own Internet exit)
> The border router MUST take the default route from Area 51 always.
>
> Well, I got this whole setup working stable for months now until last
> Tuesday. And there's a default router on the border router from area 0,
> while the Area 51 has the better metric (1) versus metric 10 and 20 from
> Area 0.
>
> QUESTIONS:
>
> 1. What is the order of operation within OSPF to select default routes
> from different processes?
>
> 2. How do I ensure the border router ALWAYS takes the default route from
> Area 51 (although it has multiple default routes from Area 0 in it's
> database)? Since OSPF metric-type 1 has preference over metric-type 2, do I
> change the metric-type in Area 51 to type 2 and ensure it's always lower
> than from Area 0?
>
>
> Looking forward hearing from you.
>
> If you need more info, please let me know.
>
> (Brian, I couldn't find any blogs on INE about OSPF multiple processes. Is
> this an idea for a future blog post maybe?)
>
> Cheers,
> Marc

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Received on Fri Jul 26 2013 - 19:18:18 ART