[194430] in North American Network Operators' Group
Re: Covering prefix blackholing traffic to one of its covered
daemon@ATHENA.MIT.EDU (Joel Jaeggli)
Mon Apr 24 11:19:51 2017
X-Original-To: nanog@nanog.org
From: Joel Jaeggli <joelja@bogus.com>
In-Reply-To: <7C10D0BB-63D9-43E9-A3C9-5971AE6DC95A@iu.edu>
Date: Mon, 24 Apr 2017 08:19:44 -0700
To: Steven Wallace <ssw@iu.edu>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
Sent from my iPhone
> On Apr 23, 2017, at 08:59, Steven Wallace <ssw@iu.edu> wrote:
>=20
> We have dual-homed sites that only accept routes from their peers, and def=
ault to their transit provider. A site may receive a covering prefix from a p=
eer, but since they are not accepting the full table from their transit prov=
ider they don=E2=80=99t see the covered (i.e., more specific). In some cases=
the peer announcing the covering prefix blackholes traffic to the covered p=
refix.
If you announce a route in general you should expect to route it.
Assuming this is the intended behavior of both parties announcing the coveri=
ng aggregate and the more specific. The site should either drop the offendin=
g peer route forcing it to transit, or take full feed from it's transit. And=
let the longest match win.
> Is this accepted behavior, or should a peer announcing a covering prefix a=
lways delver packets to its covered routes?
Generally but there are exceptions.
>=20
> Does this happen often?
>=20
> Thanks!
>=20
> Steven Wallace
> Indiana University
