From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-x22c.google.com (mail-oi1-x22c.google.com [IPv6:2607:f8b0:4864:20::22c]) (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 7B0F13B29E for ; Tue, 3 Jan 2023 04:57:20 -0500 (EST) Received: by mail-oi1-x22c.google.com with SMTP id r11so26671207oie.13 for ; Tue, 03 Jan 2023 01:57:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=domos-no.20210112.gappssmtp.com; s=20210112; h=to:subject:message-id:date:from:mime-version:from:to:cc:subject :date:message-id:reply-to; bh=Nbc81bWSd6X3m6zQ/FM8csiqRyex9g2Qq1nE61dRtZc=; b=dT+lVMe4T21m2Vzf6BgwWJqWXSldEjtq7gVaeipUoGrnsg2ALpf48VRaswE8w6+RgW bY2CLLFiQTH9bJHRFMm5eqxRCvNvhOaFd8y37dWRbnsrg5qmCF/L/h3rtV5k6NVKBYZB XLHVQ/23dFqcdtgLI7CTDqaVV/pCAo5Ms4M1dDOxx+IlpZhMks2W5Om9dgWZfeAVhs46 tnCiL1fqE6U2ny5prJvhQ+8YNiR6lv1XeaWaZ9Mf7K1xevjZrwNjWo1bG6shW7Wddcxg YcTxeAYTPSxtL/rbl6hePHrD83gJMkXvhkAKWxE140xOKN6yIgfE1HBh7FODiVIREFRR 6Zcg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=Nbc81bWSd6X3m6zQ/FM8csiqRyex9g2Qq1nE61dRtZc=; b=uXHgfpTo26HV1YvbyS6fBShJovp7j6W3vm3ME6Q8rnUp4LsFlyoXYuTU3Px3/FYNAd tLyjmqCc+U82kkIfJSRFxKt9ZhSJN+isyj9kJpx+lsm25CV+mNu1pY1MwOSsNFwMLsmH khRxw2gUDEtfey2R81g5wxjnPrxsf0scMpsWb5egysdd4CUJ2GAN/IIV/FQ2qNBCvyyl 6OZLe6WHdrmb98sbHutsitWlALIHRhz9gRuxgUXzhTZgZB5udRoR/JBrYZt7IUYRmnr+ 4wBp76vamuKq6EhDMQxp0OKHxmaYjaYQrT/k81owmpXhv/9dbFh4DPpVP/ZF7QpmtCQi YITQ== X-Gm-Message-State: AFqh2kpY1XIjWQCacWnVA+R0rUIeLHMKQ/a17TwNzSS4GI7M1Ezuj6dN r5dfk1934EIoq4LlDaJw/Q65Vz3VMOz+d0+8/ChQfetzsXIcCeuT X-Google-Smtp-Source: AMrXdXsqKkTvKsqhQ+S1z/EROYlNXPnn23yTvgR6aKOfzaa0TpTsVwZhD0TgEyOPSV7RoDueWY9aioKF6p2RsEWp5V0= X-Received: by 2002:a05:6808:1897:b0:35e:ac60:204d with SMTP id bi23-20020a056808189700b0035eac60204dmr2490436oib.100.1672739839265; Tue, 03 Jan 2023 01:57:19 -0800 (PST) MIME-Version: 1.0 From: =?UTF-8?Q?Bj=C3=B8rn_Ivar_Teigen?= Date: Tue, 3 Jan 2023 10:57:08 +0100 Message-ID: To: bloat Content-Type: multipart/alternative; boundary="000000000000ebe40905f15917bf" Subject: [Bloat] PhD thesis with results related to buffering needs on variable-capacity links 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: Tue, 03 Jan 2023 09:57:20 -0000 --000000000000ebe40905f15917bf Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi everyone, I defended my PhD in December. I hope some of the results are interesting to the bufferbloat community. The title is "Opportunities and Limitations in Network Quality Optimization: Quality Attenuation Models of WiFi Network Variability" Full text here: https://www.duo.uio.no/handle/10852/98385 Here is the abstract: The topic of this thesis is the performance of computer networks as measured by latency and packet loss. The maximum capacity, also known as bandwidth, of computer networks has been steadily improving for decades. As more capacity becomes available, new and higher bandwidth applications emerge, further increasing demand for network resources. Performance in terms of latency and packet loss has not seen the same regular improvement. Many applications convey real-time interactions, and these depend on low latency and low packet loss for optimal performance. Optimizing network latency is a complex task. Physical transmission time, scheduling, queuing, and interactions between traffic sources can all contribute to the latency we observe. The challenge of reducing latency in the Internet has received increasing attention in recent years. This attention has led to successful solutions to several issues causing latency. Other problems remain open despite these efforts. This thesis aims to extend our understanding of WiFi networks through the lens of latency and packet loss performance. We approach this using the quality attenuation metric. Quality attenuation is a way of combining latency and packet loss into a single variable. A quality attenuation value consists of a latency distribution combined with the probability of packet loss. The thesis begins by investigating which performance issues are most prevalent in today's WiFi networks. We show that both queuing latency and the WiFi protocol specification itself are significant contributors. By building a model of the WiFi protocol behavior we quantify the performance of the protocol in terms of quality attenuation. We find that significant performance variability is an inherent consequence of the protocol design. Having quantified how variable WiFi links are, we explore the consequences of this intrinsic variability for the performance of end-to-end congestion control algorithms running over WiFi. Because of the intrinsic variability of WiFi, achieving stable, low-latency networking with WiFi will require innovation on many levels of the network stack. In particular, we prove that capacity-seeking traffic can not achieve both high utilization and low quality attenuation over a typical WiFi network unless WiFi networks become much more predictable than they are today. We hope that the methods and results presented in this thesis will hasten the arrival of the low-latency Internet. Best regards, --=20 Bj=C3=B8rn Ivar Teigen Head of Research +47 47335952 | bjorn@domos.no | www.domos.no --000000000000ebe40905f15917bf Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi everyone,

I defended my P= hD in December. I hope some of the results are interesting to the bufferblo= at community.

The title is "Opportunities and Limi= tations in Network Quality Optimization: Quality Attenuation Models of WiFi= Network Variability"
Full text here: https://www.duo.uio.no/handle/10852/98385

Here is the abstract:

The topic of this thesis= is the performance of computer networks as measured by latency and packet = loss.

The maximum capacity, also known as bandwidth, of computer ne= tworks has been steadily improving for decades. As more capacity becomes av= ailable, new and higher bandwidth applications emerge, further increasing d= emand for network resources. Performance in terms of latency and packet los= s has not seen the same regular improvement. Many applications convey real-= time interactions, and these depend on low latency and low packet loss for = optimal performance.

Optimizing network latency is a complex task. P= hysical transmission time, scheduling, queuing, and interactions between tr= affic sources can all contribute to the latency we observe. The challenge o= f reducing latency in the Internet has received increasing attention in rec= ent years. This attention has led to successful solutions to several issues= causing latency. Other problems remain open despite these efforts.

= This thesis aims to extend our understanding of WiFi networks through the l= ens of latency and packet loss performance. We approach this using the qual= ity attenuation metric. Quality attenuation is a way of combining latency a= nd packet loss into a single variable. A quality attenuation value consists= of a latency distribution combined with the probability of packet loss.
The thesis begins by investigating which performance issues are most p= revalent in today's WiFi networks. We show that both queuing latency an= d the WiFi protocol specification itself are significant contributors. By b= uilding a model of the WiFi protocol behavior we quantify the performance o= f the protocol in terms of quality attenuation. We find that significant pe= rformance variability is an inherent consequence of the protocol design. Ha= ving quantified how variable WiFi links are, we explore the consequences of= this intrinsic variability for the performance of end-to-end congestion co= ntrol algorithms running over WiFi.

Because of the intrinsic variabi= lity of WiFi, achieving stable, low-latency networking with WiFi will requi= re innovation on many levels of the network stack. In particular, we prove = that capacity-seeking traffic can not achieve both high utilization and low= quality attenuation over a typical WiFi network unless WiFi networks becom= e much more predictable than they are today. We hope that the methods and r= esults presented in this thesis will hasten the arrival of the low-latency = Internet.

Best regards,
--
Bj=C3=B8rn Ivar Teigen
Head of Research
+47 47335952 | bjorn@domos.no=C2=A0|=C2=A0www.domos.no
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