BGP4 COMMUNITY attribute

Actually, along this vein (granted, this may not be the place but since
the subject came up)..

What is the general concensus about passing communities in the "community"?

See in-line below...

many of your questions are for MCI and not nanog

> In the preparation for upcoming 2nd (multihomed) connection to Internet
> I am looking into
> COMMUNITY attribute of BGP4 as a way (in conjunction with my own
> LOCAL_PREF) of load balancing
> traffic between my two internet links (both T3). After reading CISCO
> documentation I am still not
> clear on some issues:
> 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.

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


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

See my NANOG/SF presentation.