From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-x22e.google.com (mail-lb0-x22e.google.com [IPv6:2a00:1450:4010:c04::22e]) (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 CBC533B260; Fri, 20 May 2016 10:09:03 -0400 (EDT) Received: by mail-lb0-x22e.google.com with SMTP id n11so35808966lbh.1; Fri, 20 May 2016 07:09:03 -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=UXlZRp1++NKbdD3yHmph/Zc7zMlMbq8IzvGHSfTuJbw=; b=wOSOLLBFmvvzRCRINwnwTElo6kV2M4wi2bhTKxCdA8xjLZqW6+OY+008VWwrszm0l/ VBTZqj2LXa5rcH5fTYLL87C0G0nwKpfcfQ6IwRfC6HzygXroZqaS6zXBFmFGLc8ZLiKg xsOiaV2o/r+Sxu7LeWcvWEl+kKbCkIsqYcWEbRoYOx0bdHpXYrJRF6nanbr7Jdq95Mw/ v8whcRC1tSKgdqELTdOWd4iaeE5WZRrhOz5491feAyNrCRkxmTvOVRQj4XemufV5nXLM uUCoxzCIUZKyIRCJ17qZaHeLCc160azq/9q6Mcsg2BNG+N/D8e8wwoqyd6NtBUj6+gSZ YesQ== 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=UXlZRp1++NKbdD3yHmph/Zc7zMlMbq8IzvGHSfTuJbw=; b=asrLi7/MN+NLSrNluqNJLB25jUZWVx1VnAwunAXQjEfwjNr23M5x8Bl39mEinxaNLA 5wLZoObdODRZXbNtqQ+2lNdT/gZoth7loUjf5bm7hwXzbv1J2qduf6Jk2pQ1ZW14L0ml Kv4OSt+Y3KY+JF4oT6+Hcwkq2+JFzqO4FvUdoI2VQVQShZ4rFpnd51lGWFDFSGUD+JZy 98KH+osolL33d17CCdk/XWAmMDHf2n00r/i+f7KHbUzlIYzcF9lDg5Iww+NWJqOtx53x nLQTCjvKB/n3BFjSVZUeh6K2xhvDY+tqXYJMpcF4uzrVKUJAe0ewQEiwm7dTUsEC61AH l1YA== X-Gm-Message-State: AOPr4FXTOu9iHBTpRO1ToUMe+Owc2Lt0BYZqBgHJQBzgYnnpVbmM2gGNuYPl2+DkuZeBjQ== X-Received: by 10.112.10.71 with SMTP id g7mr1229252lbb.116.1463753342586; Fri, 20 May 2016 07:09:02 -0700 (PDT) Received: from bass.home.chromatix.fi (188-67-138-144.bb.dnainternet.fi. [188.67.138.144]) by smtp.gmail.com with ESMTPSA id jn5sm3327723lbc.24.2016.05.20.07.09.01 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 20 May 2016 07:09:01 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: Jonathan Morton In-Reply-To: Date: Fri, 20 May 2016 17:09:00 +0300 Cc: moeller0 , cake@lists.bufferbloat.net, codel@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: References: <22371476-B45C-4E81-93C0-D39A67639EA0@gmx.de> To: David Lang X-Mailer: Apple Mail (2.3124) Subject: Re: [Cake] Proposing COBALT 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: Fri, 20 May 2016 14:09:04 -0000 > On 20 May, 2016, at 16:41, David Lang wrote: >=20 > On Fri, 20 May 2016, Jonathan Morton wrote: >=20 >> Normal traffic does not include large numbers of fragmented packets = (I would expect a mere handful from certain one-shot request-response = protocols which can produce large responses), so it is better to shunt = them to a single queue per host-pair. >=20 > I don't agree with this. >=20 > Normal traffic on a well setup network should not include large = numbers of fragmented packets. But I have seen too many networks that = fragment almost everything as a result of there being a hop that goes = through one or more tunneling layers that lower the effective MTU (and = no, path mtu discovery does not always work) One case of which would be the misconfigured PPPoE link Sebastian = mentioned. But I don=E2=80=99t think this is as big a problem as you do. Most = latency-sensitive protocols (and critical TCP phases such as handshake = and teardown) use sub-MTU sized packets, so are less likely to be = fragmented, so will still benefit from flow isolation. And under normal circumstances, most MTU-sized packets are associated = with congestion-responsive protocols, which can tolerate being shunted = into a single AQM-managed subqueue per host-pair. Flow isolation also = still occurs between traffic to different hosts. - Jonathan Morton