[140398] in North American Network Operators' Group
Re: Downstream Usage-BGP Communites
daemon@ATHENA.MIT.EDU (Michael Hallgren)
Tue May 10 18:08:01 2011
From: Michael Hallgren <m.hallgren@free.fr>
To: nick@flhsi.com
In-Reply-To: <46995f17$60226696$3726a033$@com>
Date: Wed, 11 May 2011 00:07:13 +0200
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Le mardi 10 mai 2011 à 17:52 -0400, Nick Olsen a écrit :
> Greetings NANOG,
> Was hoping to gain some insight into common practice with using BGP
> Communities downstream.
>
> For instance:
> We peer with AS100 (example)
> AS100 peers with TW Telecom (AS4323).
> Since I happen to know that AS100 doesn't sanitize the communities I send
> with my routes. I can take advantage of TW Telecom's BGP communities for
> traffic engineering. Such as 4323:666 (Keep in TWTC Backbone). Would this
> be something that is generally frowned upon? Still under the assumption
> that the communities aren't scrubbed off my routes. Could I do this with
> other AS's beyond TW Telecom? Such as TW's peering with Global Crossing
> (AS3549)?
It's quite common, in my experience, that we remove (or at least filter;
usually looking at geo-origin ones only) BGP community values from peers
and filter them (modulo some set of agreed ones) from customers.
In other words, don't generally expect transitivity.
mh
>
> Nick Olsen
> Network Operations (855) FLSPEED x106
>
>
