From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) (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 49B6F3CB36 for ; Wed, 17 Jul 2019 17:34:08 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1563399201; bh=u20Ujds7AiP344CYKnREzw97MK4JOPrTrV4+XhJ0QY8=; h=X-UI-Sender-Class:Subject:From:In-Reply-To:Date:Cc:References:To; b=P2imBFTeln/jnxPUc+wBgkBYMmHYRovq11H2e+Ecsfkew2fPpHg2pBr0RCHP0vwIE RakAJkgmb3xy5GZ0ldtgoMjsGHxmSiQVMw2UgydbfUqvFrdvZWS4z57dlC+RKTQiK9 CyKbt1QLfSQ6mL5Ck+BH/g414T3IGFmrGwa9ExX0= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from hms-beagle2.lan ([77.190.246.243]) by mail.gmx.com (mrgmx003 [212.227.17.190]) with ESMTPSA (Nemesis) id 0MY86C-1i19Em4AYi-00UuIZ; Wed, 17 Jul 2019 23:33:21 +0200 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) From: Sebastian Moeller In-Reply-To: <350f8dd5-65d4-d2f3-4d65-784c0379f58c@bobbriscoe.net> Date: Wed, 17 Jul 2019 23:33:17 +0200 Cc: "Holland, Jake" , "ecn-sane@lists.bufferbloat.net" , tsvwg IETF list Content-Transfer-Encoding: quoted-printable Message-Id: <40605F1F-A6F5-4402-9944-238F92926EA6@gmx.de> References: <350f8dd5-65d4-d2f3-4d65-784c0379f58c@bobbriscoe.net> To: Bob Briscoe X-Mailer: Apple Mail (2.3445.104.11) X-Provags-ID: V03:K1:AmBQWzjAp7QrepDt/0RgO2k5uLZSCCtjIiPNcbzTVbXnLCPxtQa 1nk2lRDCShf9rZ1l25XcxbzjBvcPFmf7SLZqIVMXvqFWJXMKQGuBrL7Oc3XTe0U411a+w2g b/jCtjtIBtIn1T7Y2AhRT/7cnahvQzAf/MXbsKedpe9nCZVpAkST+T9XAjvXiU8OrQ+LNqD 6OhdRPJtOEbhTcUFHiGuw== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:DJbCehmlEvw=:6gqz9c/K9VxSaOASQ99HFB kapGN/k+kFhjNT0j+AfEy7ZS2MvDboNaogYt0bCKxvlcaBKSp1iHE1lOANVITjyD9viuscWMp 5+JBniomKF0yao936A+Hhi5lQvotpYo2KuMpUjBJEHh409uuzTUAwtRyx62Xk6hIpnFKa/skq KK7IvCGpdIMx3+4JyUvtxiBFYgc14DW8NNUcZM0cJ3J41aE3EKMPIAsUlBVP6N4EiAjri4wQy E26/vdJ1H1O/k+Orir6GpjUcyhb6vlhPr1ytM8hwWX7NQ1d2jPE/bsggsM9k/72U5ZIH2+pNH KulOtYEunwY0TyfQsGMCd1d1HyTDQLcnjgqJbP4Nwy38KYGu+HwqudiVlZwDxzMq/DNB4GIcU yf7iwaqSAFMTII0KlFYL0oHXJbqxihK9YKkB+hWu2nekYwKzVq4FjimGUwmOUYbSaaFnWadEN G09aRH7gmCSyPPjInWr2+iQeYiwLlRnM7LrklAEoe42qdLiFp1alSNFOCov9utOUzNP4+Tccs pqV+ZlnFNzZkwM2QnfIRsmrG98R6P0x2S7MjrnYjOm0FtsZBEELCAvv5sJWeA+IV1s2HGdt9o Q9fuU7P8xnlTtq1cRZS99u0UPbW2/PHxYaPa21g2HlD7f+bI+FFnfS3lJmOYbFX8uy4L/631P 21d+FZnMHT0M17/rPVYkxI2HOLAWmRBbiOyFr6u6z8H1Nbfuv+Dg4uI9KahCDqOLXO4ilwhme +Psvcky5wF6cnbFG2gK4UYYfmLpbCPdGbMijuiFRCE5OoGVEU2X94TsgbY9fs/nZfexMlgn8A toKxs330kdZhsyKo54rex/RJoqe0ZA/cVebxNK18TlPSV+aIiNnonlHxWfJyDi1Xx0TZUhVI1 LF3+rvFj8j5b+89mdObXGsIIepFtgyQ4AhumqYwDDeAoh4ju0upLToARzi8tGWLgXiPB55oCf AKpfeyRoWD0CPo4m2/AvvXew2IXst2zhPE7Ga/6Hdt+GcKngPSyYsqsHBj9Q7REYtqza0QFhn y3101ZU3+S8q+RqcZTKa+Ry9SPoYeJmMZCURamUboNKvRZ/UmmLPRNH5cR/fUlwTbdlOp2ml+ AdWS5Agt0dbGjk= Subject: Re: [Ecn-sane] per-flow scheduling X-BeenThere: ecn-sane@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion of explicit congestion notification's impact on the Internet List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Jul 2019 21:34:08 -0000 Dear Bob, dear IETF team, > On Jun 19, 2019, at 16:12, Bob Briscoe wrote: >=20 > Jake, all, >=20 > You may not be aware of my long history of concern about how per-flow = scheduling within endpoints and networks will limit the Internet in = future. I find per-flow scheduling a violation of the e2e principle in = such a profound way - the dynamic choice of the spacing between packets = - that most people don't even associate it with the e2e principle. This does not rhyme well with the L4S stated advantage of = allowing packet reordering (due to mandating RACK for all L4S tcp = endpoints). Because surely changing the order of packets messes up the = "the dynamic choice of the spacing between packets" in a significant = way. IMHO it is either L4S is great because it will give intermediate = hops more leeway to re-order packets, or "a sender's packet spacing" is = sacred, please make up your mind which it is. >=20 > I detected that you were talking about FQ in a way that might have = assumed my concern with it was just about implementation complexity. If = you (or anyone watching) is not aware of the architectural concerns with = per-flow scheduling, I can enumerate them. Please do not hesitate to do so after your deserved holiday, and = please state a superior alternative. Best Regards Sebastian >=20 > I originally started working on what became L4S to prove that it was = possible to separate out reducing queuing delay from throughput = scheduling. When Koen and I started working together on this, we = discovered we had identical concerns on this. >=20 >=20 >=20 > Bob >=20 >=20 > --=20 > ________________________________________________________________ > Bob Briscoe http://bobbriscoe.net/ >=20 > _______________________________________________ > Ecn-sane mailing list > Ecn-sane@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/ecn-sane