From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-x22b.google.com (mail-lj1-x22b.google.com [IPv6:2a00:1450:4864:20::22b]) (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 07D903B29E for ; Fri, 30 Nov 2018 06:04:45 -0500 (EST) Received: by mail-lj1-x22b.google.com with SMTP id c19-v6so4612353lja.5 for ; Fri, 30 Nov 2018 03:04:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=2C+tQuRLw8tFkPUshiSBTxP0wjk2oSChmjiWKhJaWsg=; b=q0uBdXo6n6BQQU6zOvhiTWdE/Du8TJD8IMS4kEbVCr196l9g6M26Kq63HoNZeBXUL0 kvHzRfL4UImFE3MAsV4nJOUn7xUmBNiK1Q57OWIsDBBcxkk8aAa8gdyeen+dTnvLPdNv GIqgIt0kiDxNcr0VbenPo+7y7vi9zDbn7Bm82PfDfNLhYetXrnfu0iIcmjUovz037gZ/ FTQsNybh6/Bt3s/tY9QUlbGfkIVOOLKi+2KOoicNmOzAE4JM2Cc72/mDQciMkDrveaA0 6OTV6lWCXGfbawNb/rtIsz0c01u7jlq3nHYA6qUpCs/oqcaDkCQ71vFWng7VmKB+PIz+ Feng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=2C+tQuRLw8tFkPUshiSBTxP0wjk2oSChmjiWKhJaWsg=; b=UvYBS+RNo5u3GqIOVKzkbNBOWUTPuseWxRafiFDlDhJh7XpCEPr1uQalA6Fvf9jmf7 uRhhsqKQbSSFtBWjSj/d7fQnGxwTRIrWki6vyvK/8Kfos6ntZn34a6TIN5fQixEd3wr9 YnQ7hq5oSeZw3jdNLrsGJPvJfKkoR9UoYH5xNgQBIUQzWJHFtw15UEudrQL4nd9nc4Li VfaCFMtRbnldCnRiNqYi5NrqyTdIW559hetA8IrDAQ/6ui2hXf0BXxU3C7WFBuCS7HZN rtdzgIxC/mp+RKWwSF2Fs5PPXaxbg9RW99jw/MGFQF9a54jjbY0SFaqhYJyFcFaEAqog +2Sg== X-Gm-Message-State: AA+aEWYiB0QRIvqENYCRT6Tvl52jdCKEsFRYW/Uh0d4xAVEZ6dF3P05a wPzJrJrsSbnTIgKhzaTT0Dc= X-Google-Smtp-Source: AFSGD/X+0Ljwv8IXF/BGNGygP0DvjKXq8795RnDHIi0vIs1EZWxwjcZNzBkymT4qdfoY3XX9x6bwpA== X-Received: by 2002:a2e:b00a:: with SMTP id y10-v6mr3439261ljk.109.1543575883827; Fri, 30 Nov 2018 03:04:43 -0800 (PST) Received: from jonathartonsmbp.lan (83-245-236-220-nat-p.elisa-mobile.fi. [83.245.236.220]) by smtp.gmail.com with ESMTPSA id 13-v6sm712314ljj.49.2018.11.30.03.04.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 30 Nov 2018 03:04:42 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) From: Jonathan Morton In-Reply-To: Date: Fri, 30 Nov 2018 13:04:41 +0200 Cc: mario.hock@kit.edu, bloat Content-Transfer-Encoding: quoted-printable Message-Id: References: <65EAC6C1-4688-46B6-A575-A6C7F2C066C5@heistp.net> <939858e1-eeff-01a3-fd35-fb3d2bbff6f8@kit.edu> To: Luca Muscariello X-Mailer: Apple Mail (2.3445.9.1) Subject: Re: [Bloat] when does the CoDel part of fq_codel help in the real world? 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: Fri, 30 Nov 2018 11:04:45 -0000 > On 30 Nov, 2018, at 12:32 pm, Luca Muscariello = wrote: >=20 > Two last comments: one should always used fluid approximation with = care, because they are approximations,=20 > the real model is more complex. Nobody considers that the RTT varies = during the connection lifetime and that ACK can be delayed. > So CWD increases in a non simple way. If I can restate that in a more concrete way: the queue may not drain at = a smooth, constant rate. There are several real-world link technologies = which exhibit this behaviour - wifi and DOCSIS come to mind, not to = mention 3G/4G with variable signal strength. - Jonathan Morton