[j-nsp] Matching specific OSPF routes in aggregate policy

[Rob Foehl]

Hey folks,

Another OSPF issue for the day: I have a somewhat specific need to match a 
route from a particular OSPF speaker in an aggregate policy, and I'm not 
having much luck coming up with a straightforward way to do so.

The route in question is injected via a type 5 LSA from a (dumb) source in 
an isolated area; the ABR is an EX, the upstream box where I'd prefer to 
handle the aggregation is an MX.  If there was a "from router-id x.x.x.x" 
match condition, it'd solve this pretty easily...

OSPF tag values are another option, but the source isn't smart enough to 
set them, and I haven't found any way to apply them to inter-area routes 
on the ABR (at least not external LSAs, anyway).

Matching next-hop values in aggregate policy works fine, but only at the 
ABR, of course.  If I do things this way, I'm stuck layering and 
redistributing aggregates within the network, which seems like more 
trouble than it ought to be.

As long as I'm willing to carry an extra route around in parallel, it'd 
likely be easiest to just redistribute the route into BGP at the boundary 
and build the aggregate from that (optionally via community match).

Am I missing any other possibilities?

-Rob