From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-x529.google.com (mail-pg1-x529.google.com [IPv6:2607:f8b0:4864:20::529]) (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 5C96F3CB43 for ; Fri, 2 Jul 2021 12:59:28 -0400 (EDT) Received: by mail-pg1-x529.google.com with SMTP id m26so10086087pgb.8 for ; Fri, 02 Jul 2021 09:59:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=wMGl3YdjFrNaY4svE+oILRjP8glzNg+Crxlksyakgpw=; b=Pl0pOXK+xyVznyEwX8mfu7OK/rpjt78THBJiTm/wmYwbMZ1+nVTm5eFNnzXuQKu5L0 UVZI0my3SRozQSEwtVzAfOq2YhygohXZhzyDEQ4jT0olWklyn3oNY/pdlZ3pcQfEn6YA lpT//8ct9tadVKg1UOx8624Ux+bLjKkPG12FKDI2j26pVL6RdMJ1+TpYKS189KM+5a/E 8+bJemElSH9Vau+bmugon2WUrm3kD6k+DINraMm+3VZTEuy9PM8Er3/HcKIc55yQqCdo 1rS7eAGHdyTNjHwMCaqGTdal0Xaf5dQMUecS57uYoCOcrN/l1e387ugncADAmutDWJP2 mRZQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=wMGl3YdjFrNaY4svE+oILRjP8glzNg+Crxlksyakgpw=; b=n+XnRGu9U3YvYoZu95a9tLHzj7lE2uG5cCXgABwj5x5P11RJAAz8QWthMuvouuZZZR 9gSN5M8PnLVmb+fzs0j5kYpzTQf588LiwPQ7y/V7L6QXoUqKY0mC4RKe/SLjFMPYIG1g h+JYGXZO1uZsxvZLJMpl+psrpLQLO7ZaWIqOMF1DIAJ/6o/eVqzZCtBmDStBSkbjhBPW /jdLW40dky7rv4X75KpzV10n5cdfrFGrMCl0BCruJq5x66j2eQOicZg4D5osdn0OnQcz A0sdGJQ/zDogjnl63OqoMdSgnokQ5JjRR6/1nptokaVUpJT5WqbYvPcw0rla4DZMWUgy J1Rg== X-Gm-Message-State: AOAM5335bsCKLhMBJaqnJc2n+QZLPPU9dptqKYBtu/7kDRb1N9Yf4BKS sIQgFnpVEcmOmY5aoj/bB/wSOw== X-Google-Smtp-Source: ABdhPJxriQx02lbwWzd+sLMPmZkUKUG49F79Aig7RUX9pBBfHMPKgBYt0kwPXcdZSph+lyBTXFQYXg== X-Received: by 2002:a63:d74c:: with SMTP id w12mr914689pgi.91.1625245167311; Fri, 02 Jul 2021 09:59:27 -0700 (PDT) Received: from hermes.local (204-195-33-123.wavecable.com. [204.195.33.123]) by smtp.gmail.com with ESMTPSA id e24sm4194117pfn.127.2021.07.02.09.59.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Jul 2021 09:59:27 -0700 (PDT) Date: Fri, 2 Jul 2021 09:59:24 -0700 From: Stephen Hemminger To: Dave Taht Cc: David Reed , bloat , Jonathan Morton , Ketan Kulkarni , "cerowrt-devel@lists.bufferbloat.net" Message-ID: <20210702095924.0427b579@hermes.local> In-Reply-To: References: <55fdf513-9c54-bea9-1f53-fe2c5229d7ba@eggo.org> <871t4as1h9.fsf@toke.dk> <3D32F19B-5DEA-48AD-97E7-D043C4EAEC51@gmail.com> <1465267957.902610235@apps.rackspace.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Cerowrt-devel] [Bloat] Bechtolschiem X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 02 Jul 2021 16:59:28 -0000 On Fri, 2 Jul 2021 09:42:24 -0700 Dave Taht wrote: > "Debunking Bechtolsheim credibly would get a lot of attention to the > bufferbloat cause, I suspect." - dpreed > > "Why Big Data Needs Big Buffer Switches" - > http://www.arista.com/assets/data/pdf/Whitepapers/BigDataBigBuffers-WP.pdf > Also, a lot depends on the TCP congestion control algorithm being used. They are using NewReno which only researchers use in real life. Even TCP Cubic has gone through several revisions. In my experience, the NS-2 models don't correlate well to real world behavior. In real world tests, TCP Cubic will consume any buffer it sees at a congested link. Maybe that is what they mean by capture effect. There is also a weird oscillation effect with multiple streams, where one flow will take the buffer, then see a packet loss and back off, the other flow will take over the buffer until it sees loss.