Re: [Idr] Vendor Defaults (was Re: Review of draft-ietf-large-community-06.txt)

Gert Doering <gert@space.net> Mon, 07 November 2016 12:13 UTC

Return-Path: <gert@space.net>
X-Original-To: idr@ietfa.amsl.com
Delivered-To: idr@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 141B01294FB for <idr@ietfa.amsl.com>; Mon, 7 Nov 2016 04:13:00 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.097
X-Spam-Level:
X-Spam-Status: No, score=-4.097 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, RP_MATCHES_RCVD=-1.497] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Lu0OUT0Pl9fS for <idr@ietfa.amsl.com>; Mon, 7 Nov 2016 04:12:54 -0800 (PST)
Received: from mobil.space.net (mobil.space.net [195.30.115.67]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 0EC001294EF for <idr@ietf.org>; Mon, 7 Nov 2016 04:12:54 -0800 (PST)
X-Original-To: idr@ietf.org
Received: from mobil.space.net (localhost [IPv6:::1]) by mobil.space.net (Postfix) with ESMTP id 4CC8B604B9 for <idr@ietf.org>; Mon, 7 Nov 2016 13:12:52 +0100 (CET)
X-SpaceNet-Relay: true
X-SpaceNet-Relay: true
X-SpaceNet-Relay: true
X-SpaceNet-Relay: true
Received: from moebius4.space.net (moebius4.space.net [IPv6:2001:608:2:2::251]) by mobil.space.net (Postfix) with ESMTP id EC608602A9; Mon, 7 Nov 2016 13:12:51 +0100 (CET)
Received: by moebius4.space.net (Postfix, from userid 1007) id DE25945EFD; Mon, 7 Nov 2016 13:12:51 +0100 (CET)
Date: Mon, 07 Nov 2016 13:12:51 +0100
From: Gert Doering <gert@space.net>
To: Robert Raszuk <robert@raszuk.net>
Message-ID: <20161107121251.GT79185@Space.Net>
References: <CAH1iCiq6jNtnkta0Bt952EQ9zOKSGt=_cCySsT5XuOKuHYO2nQ@mail.gmail.com> <86860386-9C2B-4BD5-B457-2A6DA5446CF3@cisco.com> <17E646EF-4633-423B-9AC4-B53D49C90632@gmail.com> <CA+b+ERk8NgT4RB9Hv_yrPRb2Gv2RVU9EjXUpdMc=mg0U7TeykQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <CA+b+ERk8NgT4RB9Hv_yrPRb2Gv2RVU9EjXUpdMc=mg0U7TeykQ@mail.gmail.com>
X-NCC-RegID: de.space
User-Agent: Mutt/1.6.1 (2016-04-27)
Archived-At: <https://mailarchive.ietf.org/arch/msg/idr/kvryLrRpWIovHUJwY-MizYJ4aUA>
Cc: heasley <heas@shrubbery.net>, "idr@ietf.org" <idr@ietf.org>
Subject: Re: [Idr] Vendor Defaults (was Re: Review of draft-ietf-large-community-06.txt)
X-BeenThere: idr@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: Inter-Domain Routing <idr.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/idr>, <mailto:idr-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/idr/>
List-Post: <mailto:idr@ietf.org>
List-Help: <mailto:idr-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/idr>, <mailto:idr-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 07 Nov 2016 12:13:00 -0000

Hi,

On Mon, Nov 07, 2016 at 12:16:41AM +0100, Robert Raszuk wrote:
> > The attributes changing will induce BGP churn as updates propagate.
> > That churn may in fact trigger load-induced brown-outs and further
> > induce churn.
> 
> BGP communities are not used in best path selection 

While the communities *themselves* are not, many (most? all?) major transit
providers offer communities to influence the value local-pref is set to,
on ingress from their customers.

So, if a customer sends 5539:70 or 5539:130 to us, this will end up 
setting local-pref 70 or local-pref 130, and that *will* influence 
path selection.

So, while your statement is true, it's lacking real-world consideration.

Gert Doering
        -- NetMaster
-- 
have you enabled IPv6 on something today...?

SpaceNet AG                        Vorstand: Sebastian v. Bomhard
Joseph-Dollinger-Bogen 14          Aufsichtsratsvors.: A. Grundner-Culemann
D-80807 Muenchen                   HRB: 136055 (AG Muenchen)
Tel: +49 (0)89/32356-444           USt-IdNr.: DE813185279