From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-x241.google.com (mail-lb0-x241.google.com [IPv6:2a00:1450:4010:c04::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 08E853CC23; Tue, 5 Apr 2016 16:40:52 -0400 (EDT) Received: by mail-lb0-x241.google.com with SMTP id vk4so2166197lbb.1; Tue, 05 Apr 2016 13:40:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=lpYeiZFamS9G5Px4xGIHGe3TYm/lsJkFb4k5lybPSqs=; b=c5r3bHLQaMSja4ANco93ugkiB8NR57QR34bkXI5f2ovUGhA6WRhR/h8/S0TtnqbBCN s7hvZluSMphQsw3Yb/vpHnvS3dDjLAns/bjQiJmBDuQSgOZEk761XAQab5QTyEqlxiqA Idp070qrBQ05Cxl1LDX5PHmP/NJ7a4YbldAZFlKwMYPhLyhIGeY/45UEpBvGHSj+9KrO r8eVh21QHFTLsunOwV4HhD8a4cdBUzW/wRAPfFcmdY6Mb9DmdkzKNt5fubgcYTP4QbtD GOVGWk8iJXJceG9/EhrbZdczqUXR291Z6qcTXd0GqsKTRHsPVs0fwGgajgXcQdggfrkC MOSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=lpYeiZFamS9G5Px4xGIHGe3TYm/lsJkFb4k5lybPSqs=; b=W5jNJeP6sUdcxtM0XT0VoaXPNf/udCo6yZ3Woc9SNKUQ6yj1mGH8uXaYMiqm8+TFmG uq/pQa+0uoZ3IOmJzcoFJ/5hWaZP6TFE0sSZ8piYn0hNZsE+EQQPeNQkAywIEINTorO+ +K2vG9ilcF9GgM0L+vuZRX29QqeWmBc58BqopgRxsZFt+G5WBSX7YTYYD3diI1vUJzoD pnNpe4ximngH4e5iFCeBsjrmihBKLVy/gbPXD7tExiKFsj/ZqQLMhSPTufBhgd9VeIgm bn5boRlnxj+CFiP/9j0XwcO4J8b1ysi4xOQcLvgCikQ8kMDVIjgEhn2aDf95XgTbX5NI vZHw== X-Gm-Message-State: AD7BkJK06ekvfsbCDRW1hRjORMwImyxK+WyOIEyas0DoNvd8jQ74BiIhx7P7/C4dn360SQ== X-Received: by 10.112.125.201 with SMTP id ms9mr7444535lbb.141.1459888851876; Tue, 05 Apr 2016 13:40:51 -0700 (PDT) Received: from bass.home.chromatix.fi (37-33-67-252.bb.dnainternet.fi. [37.33.67.252]) by smtp.gmail.com with ESMTPSA id h8sm5879702lbd.48.2016.04.05.13.40.50 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 05 Apr 2016 13:40:50 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.2 \(3112\)) From: Jonathan Morton In-Reply-To: Date: Tue, 5 Apr 2016 23:40:48 +0300 Cc: =?utf-8?Q?Dave_T=C3=A4ht?= , cake@lists.bufferbloat.net, make-wifi-fast@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: <4A573483-5188-4893-82B3-721AEF527534@gmail.com> References: <2415E651-1852-4B48-A9B8-553D1A2507AE@gmail.com> To: moeller0 X-Mailer: Apple Mail (2.3112) Subject: Re: [Cake] new code point proposed 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: Tue, 05 Apr 2016 20:40:53 -0000 > On 5 Apr, 2016, at 23:28, moeller0 wrote: >=20 >> Tin 0 =3D LLT =E2=80=9CLo=E2=80=9D traffic (inc. existing low-loss & = high-throughput classes), 256/256, 100%, increased target & interval. >> Tin 1 =3D Best Effort traffic, 256/256, 100%, standard target & = interval. >> Tin 2 =3D LLT =E2=80=9CLa=E2=80=9D traffic (inc. existing low-latency = classes), 256/256, 100%, standard target, reduced interval. >=20 > This might back fire, as far as I understand interval is the = reaction time window for a flow, this needs to be roughly in the = ballpark of the RTT, reducing it (significantly) will make the AQM quite = trigger happy. This might be in line with the LA proposal, but what if = LA traffic has to cross a satellite link? The entire point *is* to make the AQM very trigger-happy for =E2=80=9CLa" = traffic. By selecting the =E2=80=9CLa=E2=80=9D DSCP (or any other = low-latency DSCP, for that matter), the originator of the traffic is = requesting that behaviour. Reduced throughput is an expected = side-effect. Satellite links have nasty effects on latency-sensitive traffic all by = themselves. I don=E2=80=99t think we need to worry too much about that = combination. If the flow uses less than its fair share of bandwidth, = the AQM won=E2=80=99t trigger anyway. In any case, Codel=E2=80=99s behaviour and default parameters are tuned = for conventional TCP. Latency-sensitive traffic generally doesn=E2=80=99t= use conventional TCP, so the usual assumptions go out of the window. I = propose retaining the standard =E2=80=9Ctarget=E2=80=9D parameter on Tin = 2 to avoid triggering AQM with a single large packet, but reducing = =E2=80=9Cinterval=E2=80=9D to make Codel=E2=80=99s behaviour more = suitable for UDP and DCTCP traffic. - Jonathan Morton