From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-x532.google.com (mail-pg1-x532.google.com [IPv6:2607:f8b0:4864:20::532]) (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 5955A3CB35 for ; Fri, 2 Jul 2021 12:59:28 -0400 (EDT) Received: by mail-pg1-x532.google.com with SMTP id e20so10152927pgg.0 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=RjSsk5edlyEZt/cBAG3RO0wAoB2BvyhofLjA3o+KDujGhcjeV3iWOO9TM7KpFjmNBR UChKAE4mEpZZy3FFpbdDKDb8V1Ynyh/r0kbb0Pa0SPCdoZZcqihU0OtoLMlAghrpCmQb qGyTJiD0MCSdt2XNO9zSZ2M6p2EYQsGF6zdFssvF/sZREHKUwm33BTrdq3z9qgqSQyld 7DoaJZR6SjkelzeOfbzrQemDlb/VLVrGB3Ev9QsSnvDPrmJLEm7bPKllK1TisubdM94y /KngTo3E86t7y1HS+JFtlu1ib9eNMhK60I1sYb6GiatH51HeJtPyRSZYaRRDgcsS/wN2 4y+A== X-Gm-Message-State: AOAM530XuCiiGOgHjhoyZkbkLbxf8slTbWRsb6OaL8gaCpYQYDcbYLuH soNaH6MBONqI3WeRAB2j5ij0vw== 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: [Bloat] Bechtolschiem 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, 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.