[8380] in North American Network Operators' Group
Re: BGP4 COMMUNITY attribute
daemon@ATHENA.MIT.EDU (John W. Stewart III)
Thu Mar 27 14:48:37 1997
To: "Paul G. Donner" <pdonner@cisco.com>
Cc: Walter Towbin <Walter.Towbin@TELUS.COM>,
"'nanog@merit.edu'" <nanog@merit.edu>
In-Reply-To: Your message of "Thu, 27 Mar 1997 14:20:09 PST."
<3.0.32.19970327141852.00ff39f4@lint.cisco.com>
From: "John W. Stewart III" <jstewart@isi.edu>
Date: Thu, 27 Mar 1997 14:34:59 EST
> What is the general concensus about passing communities in the "community"?
i could see a reason for a subscriber passing communities
through a mid-level provider to a top-level provider. but i'm
not sure if it makes sense [yet] for top-levels to pass
communities between themselves
> > > 1. Is COMMUNITY a transitive attribute only between me and my immediate
> > > upstream supplier or
> > > is it being propagated further into Internet (so I can influence how
> > > somebody ,say, 5 AS hops
> > > away from me sees my routes) ?
> >
> >the attribute is defined as transitive (i.e., once associated
> >with a route it *stays* associated with the route). however, in
>
> Unless an intermediate provider deliberately changes the value, as
> opposed to appending to it.
these values aren't an end-to-end thing .. it's simply a
way for providers to more easily facilitate routing policies.
your comment implies somebody being a bad guy...
> >practice, many providers are configured to not send communities
> >to other providers
>
> Is this a conscious decision or just that they have not turned on
> "send-community"?
both. they don't turn on send-community so that others don't
see their communities. maybe they have some whiz-bang features
that make configing their neat really cool, and they don't want
others to see their communities because it might imply a way for
others to do the same thing without the same amount of work
/jws
