From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x230.google.com (mail-wm0-x230.google.com [IPv6:2a00:1450:400c:c09::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 22C2B3BA8E for ; Sun, 3 Dec 2017 06:40:09 -0500 (EST) Received: by mail-wm0-x230.google.com with SMTP id r78so1248256wme.5 for ; Sun, 03 Dec 2017 03:40:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=JH5+CVaxTWiWe4xLuLyHDqez9uF1P0gsuB9HrVJKvfw=; b=pf4N8Am0xTfQ0pT7W7uwYr8qG6qF/cYCrUdbkbUbs6E+XlryhpNvP8XzqP+l6oqPaG yl3eJHwikZ1f3cNOCmNkh+CHTYri6ha9Fe6x3YgdGFi2OXcSVSuiLFAf3WHE8e8tjErH ke1DFmXUSLUvXhufnUZ3/BxykAOWupDoLRsDgZcT6waiV13bnpGfmIy8Jp4t5Gus+3xi 4LL8EGGzwUA0MPoAeFFbcyfwBW5Qsoq3ic795hVjyROIYrKxqXgMBNdzA0OLHveuUr0y IfNmp80z6ERo0a2t7oQhh528H4Xw6Nw2dOULbQK5DyuSxlBpNRRI69+aqyOq0QOe7pud 9m+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=JH5+CVaxTWiWe4xLuLyHDqez9uF1P0gsuB9HrVJKvfw=; b=WGzWkbCmdjW/xItX+ppLtyma04p+mIVKjVLZHNVXGAriVeDTHM1p417hbaf8Ou9HWW aeg8NJydCBmbhzs2yNTPvKDHiEvylmILby3Zr9wnR3+4ywUwCafIM4DQagPXP0miZfBP CPWcM6zQuwZ3Az9EguN+NXklgRWONzGRsCXV72zWRGGIQYxT+vU2HjVEkspYKK1Tjoau 1MzUEzAKiSU5OFglGBMiR86+EZ9jxOwU1a9R96n3SKJEm692VYG6xE2B/ek8HGKO5DNf WgSa0ddoCTc6+rN5jAUFEGmK9ODzSuj75xoPdAHeZYjKutYN7HYA/jnHoJduTxpO8U+8 Rmrg== X-Gm-Message-State: AJaThX5aSvwOXgypmz2v2OvRveUSZjfH6KdJLVAT3t6DsU90lj0wHwkp eU60oQup5htPGFFfaaJWnOaEx9v2 X-Google-Smtp-Source: AGs4zMbvRq+yqPmv0L8tYu1Dg/kP7sigrgjowqNG9vOOBv2FO9SjBwyaBvh9H6IbrssAOwYFJgX2xQ== X-Received: by 10.80.148.112 with SMTP id q45mr25923453eda.161.1512301207689; Sun, 03 Dec 2017 03:40:07 -0800 (PST) Received: from zotac.xperim.be (43.16-64-87.adsl-dyn.isp.belgacom.be. [87.64.16.43]) by smtp.gmail.com with ESMTPSA id f9sm5549389edm.83.2017.12.03.03.40.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 03 Dec 2017 03:40:07 -0800 (PST) Received: from [192.168.8.184] (unknown [192.168.8.184]) by zotac.xperim.be (Postfix) with ESMTPSA id 610FE4808AB; Sun, 3 Dec 2017 12:40:05 +0100 (CET) To: bloat@lists.bufferbloat.net References: <4D0E907C-E15D-437C-B6F7-FF348346D615@gmx.de> <7B92DF4D-B6B5-4A64-9E10-119DCA2D4A6F@ifi.uio.no> <1512037480.19682.10.camel@gmail.com> <6b494910-1373-afb0-5b93-99b725391fb3@gmail.com> <87wp2638yo.fsf@toke.dk> <87tvxa36sn.fsf@toke.dk> <87po7ygxai.fsf@nemesis.taht.net> <87shcui3ni.wl-jch@irif.fr> <87shcs9k0v.wl-jch@irif.fr> From: Jan Ceuleers Message-ID: Date: Sun, 3 Dec 2017 12:40:04 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <87shcs9k0v.wl-jch@irif.fr> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Bloat] [Make-wifi-fast] benefits of ack filtering X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 03 Dec 2017 11:40:09 -0000 On 03/12/17 11:35, Juliusz Chroboczek wrote: > I'm lost here. What exact problem is the ACK hack supposed to work > around? Ridiculous amount of asymmetry in the last-hop WiFi link, or > outrageous amounts of asymmetry in a transit link beyond the last hop? My understanding is that the issue that gave rise to this discussion was concerned with upstream bandwidth conservation in the uplink of a DOCSIS network by the cable modem dropping a large percentage of upstream TCP ACKs. One element of that discussion was the question as to whether it was OK for middleboxes (such as in this case cable modems) to reduce the number of TCP ACKs, or whether instead the TCP stacks in the endpoints should be made to send fewer such ACKs in the first place. I then added more confusion by saying that in the case of wifi-connected endpoints the upstream TCP ACKs also compete for airtime with the downstream flow. Of course this no longer has anything to do with the cable modem.