From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x230.google.com (mail-lf0-x230.google.com [IPv6:2a00:1450:4010:c07::230]) (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 89BA63B25D for ; Sun, 24 Jul 2016 12:18:20 -0400 (EDT) Received: by mail-lf0-x230.google.com with SMTP id f93so114341053lfi.2 for ; Sun, 24 Jul 2016 09:18:20 -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=S2qV7ZIQMtttx/AZ0/5t5V8xavketNl9Ans53tTF8tQ=; b=yx/KyK8m6ZT6DgGA0j6eRr75ZEinXHlmwMTmgRc1lzNdcsPfeNmEerQWjc6OiYqlLC 36LT2WLDBGdosA1KtlXhztIwIlfmdjsTfB8iGivrYrSLEuCDJwjiPe55osKuOFBol//W 4DYr2vHcQEu/Jq6oGrexlJkjY3H0wCNl7W68tJQ5mrUCKeDvy/9qP7OMEt4Wi4RQRHO3 hsQ0y195kfitkardULrVGkBm6C+KHCZBAF26wYq0bdOxO1ereqnw/jIYHfXLmyDt8OYD IFYi3H55LzsMIe+ZvKFgS1xI8RGDHYfhXiiq4bcp5DYTKlvaymxb1DuZtihK59kgS8mV Qufw== 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=S2qV7ZIQMtttx/AZ0/5t5V8xavketNl9Ans53tTF8tQ=; b=NzEUMwRM4iqo4HiK9OvZEd58ayrJl77z1dIMETaUkIUe5tVgJdk3EEF8tSoWhqtIO6 CM6duK5HfilZyAs2NA2NURwuiBC9Gm3wISN0nr9gReNGv3n+r+8DiClryl5T1L6GOht+ DaJO1NFVmQhGO9NevaxETn/jW7NtWLNQCeMwEyh2G+H/Bg+k9uSTDxn3Fu6J9+/4yKTA oYmjUive5JZgZFIEXGKwhHkGWwf5yfSROXbsjzf4RUzUcbXNKSVRb/ZMeLdrBtuGVoEP K9/BvDkruOmMcf4SEKfbH8BoRiuxtYuhczT6jruLAtEQgbOsl8EYJKP6faQauRvWZUDk 0Qkw== X-Gm-Message-State: AEkoouuw73h2DcJLMaeFsKWp3W2omiXTB4mHGPYtv6pWdMaW9P2i7ckp13oezDJ5FFUSUA== X-Received: by 10.25.26.193 with SMTP id a184mr6477719lfa.219.1469377099334; Sun, 24 Jul 2016 09:18:19 -0700 (PDT) Received: from bass.home.chromatix.fi (37-33-96-207.bb.dnainternet.fi. [37.33.96.207]) by smtp.gmail.com with ESMTPSA id g11sm4785317lji.25.2016.07.24.09.18.18 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 24 Jul 2016 09:18:18 -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: <0B5FF17F-817F-4993-826D-DE55387D8D91@gmx.de> Date: Sun, 24 Jul 2016 19:18:16 +0300 Cc: Loganaden Velvindron , cake@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: <6AE56F9C-D4B5-4E64-B197-2486854B3C68@gmail.com> References: <66C89432-6E70-422F-A638-7522BF233707@gmail.com> <35967373-D9F6-4C0C-8005-787DB8C7B1BB@gmx.de> <7ECE7E7A-0310-4DC4-8AC9-29B0F1F2E383@gmx.de> <4F22259A-17C8-4353-B34B-55D7E194D1EB@gmx.de> <43469614-F02B-4D9B-8D0E-14D0F4211CF1@gmail.com> <0B5FF17F-817F-4993-826D-DE55387D8D91@gmx.de> To: moeller0 X-Mailer: Apple Mail (2.3124) Subject: Re: [Cake] fq_codel on 3g network in Mauritius 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: Sun, 24 Jul 2016 16:18:20 -0000 > On 24 Jul, 2016, at 17:40, moeller0 wrote: >=20 >>> In theory interval can be different for ingress and egress (think = old-school SAT-internet with modem upload) it probably is easiest to = only configure one interval setting for the time being. >>=20 >> Since the interval parameter depends on the RTT, not the one-way = delay, it should always be the same both ways (except for = inter-packet-time effects). >=20 > Thanks for setting this straight. I was confused; the thing that = lingered at the back of my mind was that if we do the target extension = for one direction and correct the interval in that direction, we should = also correct the interval in the other direction, especially since as = Jonathan points out the interval describes the full back-and-forth = path=E2=80=A6 To be more precise: - The overhead compensation may differ in each direction, either due to = asymmetric quirks of a particular link technology (DOCSIS), or because = different links are used for each direction (unidirectional satellite). - The =E2=80=9Ctarget" parameter must be set above one MTU serialisation = delay, otherwise a =E2=80=9Cperfect=E2=80=9D flow where each packet is = enqueued just as the previous one is dequeued will trigger Codel. Hence = the ideal target may differ per direction, if bandwidth is relatively = low and asymmetric. Cake automatically performs this adjustment. - The =E2=80=9Cinterval=E2=80=9D parameter should be higher than = =E2=80=9Ctarget=E2=80=9D by some minimum factor, which for significant = asymmetry may also cause it to differ per direction. Cake also = automatically performs this adjustment, but does not rigidly hold it to = the original recommendation of 20:1. Hence, when using Cake, it is sufficient to set an =E2=80=9Crtt=E2=80=9D = parameter (or associated keywords) consistent with expected path RTTs, = and this should be the same in both directions. - Jonathan Morton