On Sat, Jan 26, 2019 at 02:07:52PM +0700, Igor Podlesny wrote:
> I have test lab -- two OSPF routers, Bird 1.6.4: A, B.
>
> 2 areas defined: 0.0.0.0, 0.0.0.1. Export "all".
>
> When rfc1583compat is Off I observe default route gets propagated via
> area 0.0.0.1 in despite its interfaces have higher costs than area
> 0.0.0.0's have.
>
> Turning rfc1583compat On changes it to expected behaviour: interfaces
> costs are respected again.
>
> Bug or am I missing some piece of OSPF knowledge here?

Hi

I think it is correct. In OSPF, intra-area paths using non-backbone areas
are preferred over shorter backbone or inter-area paths. See RFC 2328,
section 16.4.1.