Heads up: Long AS-sets announced in the next few days

Fri Mar 4 01:09:24 UTC 2005

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