[c-nsp] IOS XR BGP

[Oliver Boehmer (oboehmer)]

> I require the specific to be from IGP.
> 
> I have a funny feeling all I need to do is redistribute OSPF into BGP
then
> use the aggregate-address as-set summary-only

yes, and it looks you can limit the OSPF redistribution to a few (a
single?) more specific as you are only interested in the core
reachability? 

> Just need confirmation if there is any other way.

not to simulate your current solution in XR. 

But have you thought about orignating the aggregates you advertise to
the Internet (and customers) via some central routers in your core, for
example some RRs, instead of on the edge(s)? This way you will never
advertise them in case your edge devices become isolated (which, if I
read you correctly, is the purpose of this exercise?).

If you chose this approach, you might also want to advertise these
aggregates with a special next-hop (like a private 10.1.1.1), and add a
static null0 to 10.1.1.1/32 on all your BGP routers. Then every router
seeing the aggregate will automatically create a Null0 and will drop all
packets to unallocated address space within these aggregates as soon as
it enters your network?

	oli