[171500] in North American Network Operators' Group
Re: Best practices IPv4/IPv6 BGP (dual stack)
daemon@ATHENA.MIT.EDU (Owen DeLong)
Fri May 2 20:14:14 2014
X-Original-To: nanog@nanog.org
From: Owen DeLong <owen@delong.com>
In-Reply-To: <7208d8ca20a14690acf8f34a934a68ec@AINET-EX13-S02.ainet.local>
Date: Fri, 2 May 2014 17:09:54 -0700
To: Deepak Jain <deepak@ai.net>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
On May 2, 2014, at 12:44 PM, Deepak Jain <deepak@ai.net> wrote:
>=20
> Between peering routers on a dual-stacked network, is it considered =
best practices to have two BGP sessions (one for v4 and one for v6) =
between them? Or is it better to put v4 in the v6 session or v6 in the =
v4 session?
Separate v4 and v6 sessions are the best practice. It is possible to =
have a single-protocol outage in which case you either take out the =
other protocol unnecessarily or you black-hole traffic.
> According to docs, obviously all of these are supported and if both =
sides are dual stacked, even the next-hops don't need to be overwritten.
Mostly true, but implementations vary and YMMV vendor to vendor and in =
some cases, model and/or software version to model and/or software =
version. Two sessions always works and unless you are somehow =
resource-constrained on sessions is really the simplest, easiest to =
manage, cleanest way to do things.
> Is there any community-approach to best practices here? Any FIB =
weirdness (e.g. IPv4 routes suddenly start sucking up IPv6 TCAM space, =
etc) that results with one solution over the other?
See above for BCP. As to the rest, in my experience, the answers vary =
(see above).
Owen
