iBGP and Next-Hop cost

[Adam Priestley]

On 10 September 2015 at 12:03, Ondrej Zajicek <santiago at crfreenet.org>
 wrote:

>
> I examined it and for some reason[*] BIRD does not accept OSPF type-2
> external metric as IGP metric for the purpose of recursive route
> comparison. There are two solutions, either export that static routes to
> OSPF as type-1 external routes instead of type-2 external routes, or set
> the ipg_metric route attribute explicitly in OSPF import filters (e.g.
> 'igp_metric = ospf_metric1' would use ospf_metric1 always even for type-2
> external route).
>
> [*] Probably because type-2 external routes have both type-2 metric and
> regular metric, both have 24-bit range and it would be problematic
> to compress that into 32-bit igp metric range.
>


Hi Ondrej,

Thanks for your assistance. I will try what you've suggested, but I'd just
like to make sure I understand you.

You mention static routes, but there are none in my configuration. OSPF is
learning linknets and router loopbacks only, this particular /32 is only
ever known to BGP. Are you saying that when OSPF is learning the linknets
that ultimately provide the routes used for next-hop, I should be applying
the 'igp_metric = ospf_metric1' filter?

Thanks again.




Adam Priestley
Network Administrator
Packnet Limitedt: +44 (0)161 660 2350
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