From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from iramx1.ira.uni-karlsruhe.de (iramx1.ira.uni-karlsruhe.de [IPv6:2a00:1398:2::10:80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id CF8593B2A4; Thu, 28 Jul 2022 04:45:37 -0400 (EDT) Received: from i72vorta.tm.uni-karlsruhe.de ([141.3.71.26] helo=i72vorta.tm.kit.edu) by iramx1.ira.uni-karlsruhe.de with esmtpsa port 25 iface 141.3.10.8 id 1oGz9D-0002gT-8K; Thu, 28 Jul 2022 10:45:35 +0200 Received: from [IPV6:::1] (ip6-localhost [IPv6:::1]) by i72vorta.tm.kit.edu (Postfix) with ESMTPS id 23F40D00006; Thu, 28 Jul 2022 10:45:35 +0200 (CEST) Message-ID: Date: Thu, 28 Jul 2022 10:45:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.11.0 Content-Language: en-US To: Dave Taht , starlink@lists.bufferbloat.net, codel@lists.bufferbloat.net References: From: "Bless, Roland (TM)" Organization: Institute of Telematics, Karlsruhe Institute of Technology (KIT) In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ATIS-AV: ClamAV (iramx1.ira.uni-karlsruhe.de) X-ATIS-Checksum: v3zoCAcc32ckk X-ATIS-Timestamp: iramx1.ira.uni-karlsruhe.de esmtpsa 1658997935.292478395 Subject: Re: [Starlink] Finite-Buffer M/G/1 Queues with Time and Space Priorities X-BeenThere: starlink@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Starlink has bufferbloat. Bad." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Jul 2022 08:45:38 -0000 Hi Dave, IMHO the problem w.r.t the applicability of most models from queueing theory is that they only work for load < 1, whereas we are using the network with load values ~1 (i.e., around one) due to congestion control feedback loops that drive the bottleneck link to saturation (unless you consider application limited traffic sources). So I'm not sure that you can expect interesting results from these kind of models to understand FQ-codel 's behavior w.r.t. to "real traffic". So it also depends on how accurately one can model the real traffic source aggregate that is actually a mixture of short-lived and longer-lived flows with a CC feedback loop. Regards, Roland On 27.07.22 at 17:34 Dave Taht via Starlink wrote: > Occasionally I pass along a recent paper that I don't understand in > the hope that someone can enlighten me. > This is one of those occasions, where I am trying to leverage what I > understand of existing FQ-codel behaviors against real traffic. > > https://www.hindawi.com/journals/mpe/2022/4539940/ > > Compared to the previous study on finite-buffer M/M/1 priority queues > with time and space priority, where service times are identical and > exponentially distributed for both types of traffic, in our model we > assume that service times are different and are generally distributed > for different types of traffic. As a result, our model is more > suitable for the performance analysis of communication systems > accommodating multiple types of traffic with different service-time > distributions. For the proposed queueing model, we derive the > queue-length distributions, loss probabilities, and mean waiting times > of both types of traffic, as well as the push-out probability of > delay-sensitive traffic.