From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.22]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id A6B9621F41A for ; Sat, 13 Jun 2015 00:13:58 -0700 (PDT) Received: from hms-beagle-6.home.lan ([217.237.71.188]) by mail.gmx.com (mrgmx103) with ESMTPSA (Nemesis) id 0Mhhr5-1YglSj3Ljn-00MuiR; Sat, 13 Jun 2015 09:13:54 +0200 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) From: Sebastian Moeller In-Reply-To: Date: Sat, 13 Jun 2015 09:13:52 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <6AD8E150-5751-43AC-8F6C-8175C1E92DE1@gmx.de> <08DFF433-9457-4A3A-92AA-A3B97828F444@gmx.de> To: Alex Elsayed X-Mailer: Apple Mail (2.1878.6) X-Provags-ID: V03:K0:9J0qt4ADTCWL2UjcHLjJdUY2mdWgFWhnUQsOaXUMc+R581U0jOA CjZXV2JYWuhbPrcFquJjuxFAxxvKM68OmiipqCFuQYNnqPRdoP7XqBdyA/UePRYAugoRSrp z+iBcuunNEJN6bfwhzBGDfp1qvt4ACv09GV3N3JBQ+xO7EGV3QxoC0FVTxD0+ntRSIgNymb oXVbG9w8BvbvtpTxtSTgA== X-UI-Out-Filterresults: notjunk:1;V01:K0:cn4iNbdcXVs=:dyqjCQZWXbaztW/4mHFKuj taq/8qQfTiAxN12ChR+oTtItQtIuMT7kpyLtqjcbZUlJVXK5h0aic0Nzosx6jU8UY77nJpTMo XP6Vsx/3czxNLnnmIyZelhJXkhXs4tm448VP+EUx/rFZbCqucPiiToW7NrLPC/SZQ93iViQZE Yij/y8UtAQk2Gxn2yf7ISwSZ6Xi9hwnn47bUO73c1Ob9VuCRYcnWJd4awj/6CIHx1AljdJLda d+4fpMjPRnWbfsm8CvrcXVP1p3OBhaaYMSKBSlGPQPzYrkVla/oIHNj33EwMSaQCUYf51N+Ty PCvPoAWcB4I4GlEkUfWUv03VTtLy9n0hEBJWef3sDkuJDjcIq1Si9VDGmr+MMLB3Qxjo4UNmf ZGq4F2vOFq6zqyexBJhebu4ccxV78RHwGcA2cx8m3jxe9LArOjd+SJOgoOO+EIg6sx24Gdxqb mrkpM70r7ceeNfmSPtayQbscCIKFl0RO+ObyXXcgVHfpQNXBzFPmFBbX6emXChSoUdgX6w+/N sgHxco1SU+glnj1BRxoH2XqRKM09NBPLKJTH0pehBWkith0bKhk7H4itZmf1gg0RLRrb9RBGD OZjb0J8Zr7nUk+NSFPeHEMsFOuI2pLUuO8zs50HEuXOhXt1ZpfJqzDLbVJ7H/i1jtbTAnfRei TjiAo6FdFNFVpEVEeT0Z9NStuhWbCpfZnWciZ0RcixM7KRyAp+QKUM0LsfYKDiBWr3ZE= Cc: bloat@lists.bufferbloat.net Subject: Re: [Bloat] Bloat done correctly? X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 13 Jun 2015 07:14:27 -0000 Hi Alex, On Jun 13, 2015, at 00:56 , Alex Elsayed wrote: > [...] > Sure, the access link is debloated. But there's also the remote = downlink,=20 > etc. Our access link may not be the bottleneck for the ACKs. I am confused now, prioritizing ACKs will only work (reliably) = on the access link (for normal end users, business contracts might be = different) and the ISP will either ignore them or re-map them to zero. = Often enough the access link really is the relevant bottleneck, but you = are right there a number of situations where the congestion is upstream = and neither de-bloating the home link nor prioritizing ACKs in the home = network will help. >=20 > And yes, boosting sparse flows is likely a more beneficial behavior = than=20 > prioritizing ACKs specifically (especially on deeply asymmetric links) >=20 >>>=20 >>> 1.) back off sending when the sending channel is not congested and >>> 2.) resend a packet that _already arrived_. >>=20 >> But TCP ACKs are cumulative so the information from a lost ACK are = also >> included in the next, so you need to loose a stretch of ACKs before = your >> scenario becomes relevant, no? >=20 > Sure, though again the local access link isn't the only possible = source of=20 > congestion. But isn=92t it the only link that is sufficiently under our = control to allow to implement remedies? > [...] >=20 > Sure, debloating more thoroughly is the best solution. It's just a = nonlocal=20 > solution, and until debloating conquers the world, local solutions = have a=20 > place. So currently the observation is that for most situations even = 1-tier shaper+fq_codel as implemented in sqm-scripts helps to fight = access link buffer bloat efficiently enough that ACK-priritization does = not seem to be needed nor recommended anymore (well unless your router = only allows playing ACK-games but does not offer flow fair queueing) Best Regards Sebastian