From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from order.stressinduktion.org (order.stressinduktion.org [87.106.68.36]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "order.stressinduktion.org", Issuer "order.stressinduktion.org" (not verified)) by huchra.bufferbloat.net (Postfix) with ESMTPS id C903721F17D for ; Thu, 27 Dec 2012 13:25:07 -0800 (PST) Received: by order.stressinduktion.org (Postfix, from userid 500) id DA95B1A0CDAE; Thu, 27 Dec 2012 22:25:04 +0100 (CET) Date: Thu, 27 Dec 2012 22:25:04 +0100 From: Hannes Frederic Sowa To: Rick Jones Message-ID: <20121227212504.GC20131@order.stressinduktion.org> References: <20121227023728.GB19548@order.stressinduktion.org> <50DCAB3B.5010902@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <50DCAB3B.5010902@hp.com> Cc: bloat@lists.bufferbloat.net Subject: Re: [Bloat] enabling outgoing tcp-ecn by default for ipv6 links X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Dec 2012 21:25:08 -0000 On Thu, Dec 27, 2012 at 12:10:35PM -0800, Rick Jones wrote: > On 12/26/2012 06:37 PM, Hannes Frederic Sowa wrote: > >I am thinking about advancing the ipv4/tcp_ecn knob in linux to > >distinguish between ipv4 and ipv6 transport and enable ecn signaling > >on outgoing ipv6 connections by default (for me, at least). I am > >currently doing so with the help of iptables (echo 1 > tcp_ecn and -j > >ECN --ecn-tcp-remove). > > Any particular reason you aren't willing/able to just flip the > net.ipv4.tcp_ecn sysctl to turn it on for both? FWIW, that is what I > have done on netperf.org, with an eye towards seeing what ceases > working. Thusfar things seem OK. At least I've not had anyone contact > me to say "Hey! Why can't I reach netperf.org!" ... But ecn is not employed as long as your clients won't signal ecn support, too. So there is nothing to break. I have a squid server where I actually needed to disable outgoing ecn support because of reachability problems to a german university last year. This seems to be fixed this year (and they have enabled ipv6, thus supporting my assumption :) ). I suppose there are still many ecn-blackholes rendering enabling ecn by default unlikely. I am a bit more confident this could work some day for ipv6. Greetings, Hannes