From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-x229.google.com (mail-ob0-x229.google.com [IPv6:2607:f8b0:4003:c01::229]) by lists.bufferbloat.net (Postfix) with ESMTPS id AB5F13ED8C for ; Wed, 23 Dec 2015 07:41:26 -0500 (EST) Received: by mail-ob0-x229.google.com with SMTP id iw8so163528900obc.1 for ; Wed, 23 Dec 2015 04:41:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=xqiNTThuuYA+5I4MuwWiZNE0lNlSCoPeoA0MrnIzfO4=; b=lZz1qHlRsre1mFSAejJ2mV58p+ev98nK4Gz6y4k88xpfxZBiXdT4arhpO3FzXs1kRs OqieYqwT+cgornRSTvXJvD6IqWDCcNW3o1zWXGJAKQuD86R0gnXT2HhK3CV+VAWfXTDl mIwnhMxpvwDUA9U7C4CkB2dsbaufLwbBoKjKe2rm7qh3Wa2bepizC0Q+55vkwllr3pZ9 Enuslf/LkX47HTLlMf1JcrCFW+Zh0m4q1dONpcK4MPJ5b29V3iFa0Z6atK0sxws9EH2D W9pB1QhJylbUS3R9/01RRSaNQkTlUi6Zvb0+ghPCYG+iO7hZho36/iYBhs//1YFPUfhB rp5A== MIME-Version: 1.0 X-Received: by 10.182.236.3 with SMTP id uq3mr13521008obc.25.1450874485731; Wed, 23 Dec 2015 04:41:25 -0800 (PST) Received: by 10.202.187.3 with HTTP; Wed, 23 Dec 2015 04:41:25 -0800 (PST) In-Reply-To: References: <6F86FBB0-AA69-44F3-82D0-31465906974D@gmx.de> <56657A82.2080601@darbyshire-bryant.me.uk> <95560E7E-DEAF-40D8-B704-CEA38A0CDE62@gmx.de> <85A5A21C-E468-4F81-8A36-0F1AD6C84435@gmx.de> <5679CF0F.4080506@darbyshire-bryant.me.uk> Date: Wed, 23 Dec 2015 13:41:25 +0100 Message-ID: From: Dave Taht To: Jonathan Morton Cc: Kevin Darbyshire-Bryant , moeller0 , cake@lists.bufferbloat.net Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Cake] second system syndrome X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 23 Dec 2015 12:41:27 -0000 On Wed, Dec 23, 2015 at 1:27 PM, Jonathan Morton wr= ote: > >> On 23 Dec, 2015, at 13:43, Dave Taht wrote: >> >> squashing and washing are both well within the realm of ietf best >> practices. It is highly desirable to have this level of simple control >> on cake for inbound - for example, 90+ of all comcast traffic, no >> matter how originally marked, comes in marked as background, and >> should be changed to best effort on the gateway. Doing so with an >> iptables rule is inefficient and it is difficult (along with the rest >> of sqm-scripts) to hook into other people's iptables rules. > > My argument is simple: if you care enough about Diffserv to notice Comcas= t meddling with it, you almost certainly want to do something *much* more s= ophisticated than just =E2=80=9Cwash=E2=80=9D or =E2=80=9Csquash=E2=80=9D. Preserving nearly all traffic as mis-marked as background does bad things to 802.11e. > The one exception I can think of is where the untrusted DSCP interacts ba= dly with some congested internal-network equipment - such as a long wifi li= nk - that can=E2=80=99t be reconfigured to ignore untrusted DSCPs. So I ca= n see why you specifically are interested in the =E2=80=9Csquash" feature, = but pretty much nobody else will be. =E2=80=9CWash=E2=80=9D is just plain = wrong. > > Given that this entire thread is about concern over scope creep, changing= the DSCP is my line in the sand. Doing it properly is out of scope, so do= ing it *at all* is *also* out of scope. > > What =E2=80=9Cwash=E2=80=9D and =E2=80=9Csquash=E2=80=9D have done, thoug= h, is to show that changing the DSCP in a qdisc can be done. Hence, it sho= uld be straightforward to implement a qdisc, which can be stacked with Cake= or any other Diffserv-aware qdisc, that covers the common use-cases proper= ly and without the major overhead of firewall rules (which, in any case, ap= ply too late to be useful on ingress). I have some ideas, which I intend t= o detail separately. > > As a compromise, I=E2=80=99ll leave =E2=80=9Csquash=E2=80=9D and =E2=80= =9Cwash=E2=80=9D in place (since they=E2=80=99re already there) until a bet= ter solution is available. Great. Let's move on. Are you actually testing your codel changes at longer RTTs? > - Jonathan Morton >