From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-x62b.google.com (mail-pl1-x62b.google.com [IPv6:2607:f8b0:4864:20::62b]) (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 ED40A3CB37 for ; Thu, 4 Aug 2022 19:24:43 -0400 (EDT) Received: by mail-pl1-x62b.google.com with SMTP id z19so1194997plb.1 for ; Thu, 04 Aug 2022 16:24:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=3QRuaYXHVFU0oM1gmrS9Qitnd82yxJJ+6e/igDBMMfE=; b=Mdic8p08GnSMTNtDjj78/YTbvkTjQ+P3w0lVOVz9zm13u1fcI7RKaTkvehZF8HDb6+ Lc0RMrihgYE05R1cFVSvnqafuJxrCtaDcmvfsc/QyC2GszAZORlx4pIdc8TC2lbtt3b0 OpSAd7pHGn5VM3fX0RT0FbPD4qNJwaMwOiz3ooOnEDlDL4jnVbALO/lwgnfeBrvBbOFO Skgmw9F+7NwykEksuNSEGrYuyYWnYO8g3J/6cLuEqhllhK7IjeoPYIdJ+ddwpIKD3BP6 2BxUrLm1dEGahnepy1FLFnx7D+4qmTjhJI4KSYd0Mha3sM/Z7xJLEq5VndNt6+L1hxfs uBuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=3QRuaYXHVFU0oM1gmrS9Qitnd82yxJJ+6e/igDBMMfE=; b=xCL7dO9UY3kovLdMBjn8RpvrV2HGNlrKPTPG9BAHaQqXYf7bAIgNjhSRVkKSkCTk3c ex9uQ6RXxuVQl+AuDHlIPOWFYMEYYQ+4QV4qaPqx2Q5Z8tMkCh9Wn1pAO83qcI8Er3MM b8uZdDtFI7QyWndzxmJOJPRzYnslSpfoyitmBGtpWBKaW4KIPcCEvZ5yErRZChHRjNZm EGnHgcTKZhYokdeRe5Or0G8DcL0aexIhiksT2mDVz2U5VudABEmvEetfCU2yI9o5C7Xp mdFnlUSeUh7V8H/JQ5GMxCpz94S7QVOQS5nUsOkW17XM4Sux2Ngv+T9OkemCFW4/zx3a 7jaQ== X-Gm-Message-State: ACgBeo2FtGGRN1rZXfEOags1IbR563rREkwq04pOHbfh2KS1gSBshsyV SzsQAKFihawFbNu4Boo+dLhPXYdWkX62ww== X-Google-Smtp-Source: AA6agR7AUDI1CJtJPngbmBssLiTApTnei6jFm/m1ywGdUyoVRMNkatYIniqjSaLG0Xd30SsTwy1fqw== X-Received: by 2002:a17:902:ab0f:b0:16d:b340:bf8f with SMTP id ik15-20020a170902ab0f00b0016db340bf8fmr3976131plb.140.1659655482559; Thu, 04 Aug 2022 16:24:42 -0700 (PDT) Received: from hermes.local (204-195-120-218.wavecable.com. [204.195.120.218]) by smtp.gmail.com with ESMTPSA id s7-20020a170902988700b0016f8e8032c4sm356062plp.129.2022.08.04.16.24.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Aug 2022 16:24:42 -0700 (PDT) Date: Thu, 4 Aug 2022 16:24:40 -0700 From: Stephen Hemminger To: Jonathan Morton via Bloat Cc: Jonathan Morton , =?UTF-8?B?QmrDuHJu?= Ivar Teigen Message-ID: <20220804162440.57fd5201@hermes.local> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Bloat] Researchers discover major roadblock in alleviating network congestion 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: Thu, 04 Aug 2022 23:24:44 -0000 On Fri, 5 Aug 2022 00:45:12 +0300 Jonathan Morton via Bloat wrote: > > On 4 Aug, 2022, at 3:21 pm, Bj=C3=B8rn Ivar Teigen via Bloat wrote: > >=20 > > Main take-away (as I understand it) is something like "In real-world ne= tworks, jitter adds noise to the end-to-end delay such that any algorithm t= rying to infer congestion from end-to-end delay measurements will occasiona= lly get it wrong and this can lead to starvation". Seems related to Jaffe's= work on network power (titled "Flow control power is non-decentralizable")= . =20 >=20 > Hasn't this been known for many years, as a consequence of experience wit= h TCP Vegas? >=20 > - Jonathan Morton It seems like BBR developers thought they could do better. Unfortunately, p= apers with negative results never seem to get written or published ;-(