[78426] in North American Network Operators' Group
Re: Heads up: Long AS-sets announced in the next few days
daemon@ATHENA.MIT.EDU (Lorenzo Colitti)
Thu Mar 3 20:09:23 2005
Date: Fri, 04 Mar 2005 02:09:24 +0100
From: Lorenzo Colitti <lorenzo@ripe.net>
To: Niels Bakker <niels=nanog@bakker.net>
Cc: nanog@merit.edu
In-Reply-To: <20050303232440.GQ33864@snowcrash.tpb.net>
Errors-To: owner-nanog@merit.edu
Niels Bakker wrote:
>>>Every piece of BGP documentation I have ever seen says that this
>>>attribute documents the ASes that the route has actually passed
>>>through.
>>
>>I think the above paragraph of RFC 1771 disagrees with you.
>
> Please quote properly; the context was AS_path, not AS_set.
> David Schwartz was right on the mark here.
As far as the RFC is concerned, the AS-set is part of the AS-path. See
Section 4.3, which says the AS-path is "a well-known mandatory attribute
that is composed of a sequence of AS path segments. Each AS path segment
is represented by a triple <path segment type, path segment length, path
segment value>," where path segment type is 1 for AS_SEQUENCE and 2 for
AS_SET.
The RFC also says:
> An AS_SET implies that the destinations listed in the NLRI can be
> reached through paths that traverse at least some of the
> constituent autonomous systems.
which is exactly what we are doing.
Regards,
Lorenzo
