From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ej1-x633.google.com (mail-ej1-x633.google.com [IPv6:2a00:1450:4864:20::633]) (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 F02763B2A4 for ; Wed, 6 Apr 2022 20:52:42 -0400 (EDT) Received: by mail-ej1-x633.google.com with SMTP id a6so7774240ejk.0 for ; Wed, 06 Apr 2022 17:52:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=vDdhoQcAiaIhGEuXreB1yOD8TPwm2tdEMLyUVodEHl4=; b=LOjO23ZXF+OWPzmeJDseOHWfXYohRiLJCr7r/04EfhZbbbhDvKgF2YTX0lPt/7sEhn GEN2+OCurAg8yoI/breBBtYVDpexPnJ3AFYRHZ1GgBOmaQ136rYFfUsvQ2x0sC+wBjwX QI/OSwzdUWctPo5ntCaTJ48TSSc3hV7n7O5o09gxNWfUqsSHiV+D0fuHI4VUOmB4wFrM pmUTHZZIAzIj6VKHLA6yZIygGLX25BGLrAu4CoYzzO527AW+cbb5JTHTwkXw6N0JG4IC v/7pg+ahQTCaaeokuyHzCxgfxHrpy3WxRvu6wjXlnuWmBwWuf1qlCtQvCWWx6CoP58ZW NqXQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=vDdhoQcAiaIhGEuXreB1yOD8TPwm2tdEMLyUVodEHl4=; b=70hQh8XdxrYknvb2sfcl78FXlj9MgUJlfRC/yNyg2v2mIQ8520OtY8omfPqrNbrq20 M0itOZBtxTqFWFHzEGL/97+ksQ7rh99jWde52jSv6kFrpP81hWILc3zho2j3yILU1muI r1PpzDdynGX7VqwmOHn2/5zfiTfNmp22U3bOCdqUo3asJKZM+i9Ul1eVXg8UPv0rPPod cnw5nafPQSagPtWE5wguU3/ZCHzRWXlDo/Q1t1l8/kue3mo/OcSuv6O8jH8i7n5r4b5Y MrdcdurqzFuGJgSA0dgTVhkMdEKJ5xlMwV9uCU8k2/3XFE6xLOeqaCI+SjF9icve2xdI c6DQ== X-Gm-Message-State: AOAM533EXtpbJQ8o5KrgBrZQ0fnmBYzo26cCV0RpPrloxHyfVUPQis3o 04fzQDfrZRMDlTnpGbCIWwPisRZrJErGhXYaXeGMLAt0w94= X-Google-Smtp-Source: ABdhPJxjWg9p9hjppfTQAq/xMq4U34JRp1FWF5p8130qQBvo1wRx2f1PomMZREZ0QWAHCqukmRUPjQVwVWzfhO6xnfU= X-Received: by 2002:a17:907:2d93:b0:6db:ab5e:7e0b with SMTP id gt19-20020a1709072d9300b006dbab5e7e0bmr10806148ejc.262.1649292761664; Wed, 06 Apr 2022 17:52:41 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Dave Taht Date: Wed, 6 Apr 2022 17:52:34 -0700 Message-ID: To: Qian Li Cc: bloat Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Bloat] less than best effort: TCP - flexis - A New Approach To Incipient Congestion Detection and Control 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: Thu, 07 Apr 2022 00:52:43 -0000 On Tue, Apr 5, 2022 at 8:44 AM Qian Li wrote: > > Dear Dave, > > Thank you for your interest in my work. > > I have read another paper authored by D. Rossi at el. presenting the prio= rity inversion problem of LEDBAT when it is used together with AQM. And it = has become one of the factors that motivated me to devise a new LBE CC that= can preserve low priority even when AQM is used. We'd given up hope circa 2014 as of the publication of the paper I cited, and moved on. >However, I could not test FlexiS with CoDel on the CORE emulator probably = because CoDel drops packets at the dequeue time. I don't really understand that statement. > More tests should be done to verify that FlexiS does preserve low priorit= y in the presence of various AQM algorithms. Yes. until fairly recently I had had a testbed setup that allowed testing of various tcps and aqm systems, but its been in storage since covid. > I am now adapting FlexiS to the receiver side. The main motivation to do = so is that there might be HTTP/TCP proxies between the sender and the recei= ver. A receiver side LBE CC and make the connection between the proxy and t= he receiver LBE. In this work, I am going to tackle some open issues with F= lexiS. For example, I am going to test if trend analysis can be done based = on one way delay so that the throughput is less affected by ack path conges= tion. And I am going to evaluate various techniques to reduce rate below 2 = mss per RTT. This may include what you have suggested -- use small packets = and sub-packet window. I am also interested in using pacing to slow down se= nding rate and maybe more alternative solutions. Cool! > > I don't have a git tree for the source code mainly because I don't know i= f I am allowed to publish the code as open source. If you are interested in= the source code, I can ask the University of Oslo if I am allowed to distr= ibute it freely? I would hope they would allow publication. The world is full of half baked projects that if only someones new also stepped in, were completed. An example of this is BBR which originally was about half what it is today, until source was released among the right people. > > Best regards, > Qian > > > > On Sun, Apr 3, 2022 at 6:38 AM Dave Taht wrote: >> >> Dear Qian: >> >> Pretty promising paper. I liked that it tackled congestion on the ack >> path, among other things. >> >> https://www.techrxiv.org/articles/preprint/TCP_FlexiS_A_New_Approach_To_= Incipient_Congestion_Detection_and_Control/19077161/1/files/33905018.pdf >> >> I like also that you tackled, inter-rtt fairness, and, ledbat's >> latecomer advantage problem, and in fig 9, the basic problem with >> delay based LBE vs AQMs (in that ledbat degrades to reno)... [1] >> >> Towards your conclusion... >> >> I have always disagreed with the "don't reduce segment size" crowd, >> btw. If you have a rate where you need to go below 2mss, it doesn't >> hurt the network to reduce the size of the packet, and you can keep >> the signal strength up by reducing that size and continuing to sample >> rtt, to respond quickly. >> >> Even if you are only passing a single byte of data, by lowering this >> below everyone else's 2mss noise floor, you still eventually win, and >> also you occupy space in packet fifos, reducing overall latency, as >> bytes=3Dtime. IMHO. >> >> elsewhere, sub-packet windows are being experimented in bbrv2, I'm >> told, but not in LBE. >> >> I'm also a big believer in packet pacing, and I think this is the >> first paper I've seen that attempted LBE with it. Thx! >> >> Got a git tree? >> >> [1] do wish you'd had cited >> https://perso.telecom-paristech.fr/drossi/paper/rossi14comnet-b.pdf >> >> -- >> I tried to build a better future, a few times: >> https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org >> >> Dave T=C3=A4ht CEO, TekLibre, LLC --=20 I tried to build a better future, a few times: https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org Dave T=C3=A4ht CEO, TekLibre, LLC