From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-x12c.google.com (mail-lf1-x12c.google.com [IPv6:2a00:1450:4864:20::12c]) (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 2967F3B29E for ; Wed, 29 Apr 2020 05:46:23 -0400 (EDT) Received: by mail-lf1-x12c.google.com with SMTP id d25so1086635lfi.11 for ; Wed, 29 Apr 2020 02:46:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=Gw+MBHu2EBhiVfpnR7LzS5Mz94m1hgrOj3ltFm4QgRc=; b=Y3oQYToFc6XVB5E2RgbbF7T307w4KWS5qYJA27w7XBMTz8VAjBuLeSxpbm3nwj4IZR mESHlbdZwWWrVRz2rW8PQvTOuwTmSVUOOceFBz+pjzlWKU+kBYIW2BC7bS+ZkiYOUzyB 6J0LG8gJz8mZdjRkl8tRz2IfR6Hezok/XmC/MnhUkgyQg1xfD3G2pJyE6Zsb7y34IHbq FyHHk+MZlleF4T85qU6dJcqcHd2YyCqRnj4RycHu8Ft4TUFDcfXgGTyxPyliTqdFmxR3 Nb7a6CC8ZLKfH1Wev7/5HhYNXKshnbLF7UXL2XPHt8US8jlmjTXkGiTm0G1vs6PujRUn F1lA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=Gw+MBHu2EBhiVfpnR7LzS5Mz94m1hgrOj3ltFm4QgRc=; b=d0ukbCX+Sc7F0a7hx0FLcocLEwZ7OcuFTReUL4bvgw0bNiu+qNrWFfJmqFpiuOY4SJ 5qbLKtOyj6Il36GOhoVlwWKmnEuBI73sWXRdTKfu9lbTKAcpslxqiuMmIZPrJF0tN1ZI j5Qxym5/KMPq2R+qP5z8UC5YAnNspg7gEVWsB33YansBInxwTEHPorZjcpxvxHIdtM/9 +q8D3avxy3U/LF+0ot3A7rHlzwoG7OR4z5JU80JKJuOLRgiXKrhaTbtab0uqerzyxZWI pqjRs4VPCLAklvHqpdLywrhw9KTV7CrVccHTV6Eme+0IhMriLQFXPtmzkByOwmJKi04D 9Jwg== X-Gm-Message-State: AGi0PuZGoxsSuq72R8A44kMOwBuiz1xrfa7QjLbGIucRHyZSBIgWgsDG yMLqoBlpMraeWQyQ1ZsJ16o= X-Google-Smtp-Source: APiQypJVLHeDEBr+9VMI2F4uDoYUZwTTCWhIHs7/rdKI9zfRLlBJzw7ofKmG+RCkPVufCB/VU164YQ== X-Received: by 2002:ac2:489b:: with SMTP id x27mr22482194lfc.60.1588153582052; Wed, 29 Apr 2020 02:46:22 -0700 (PDT) Received: from jonathartonsmbp.lan (83-245-235-192-nat-p.elisa-mobile.fi. [83.245.235.192]) by smtp.gmail.com with ESMTPSA id r23sm2222775lfi.33.2020.04.29.02.46.21 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Apr 2020 02:46:21 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) From: Jonathan Morton In-Reply-To: Date: Wed, 29 Apr 2020 12:46:20 +0300 Cc: "Rodney W. Grimes" , tsvwg IETF list , bloat Content-Transfer-Encoding: quoted-printable Message-Id: <4439559D-35A6-47A3-8827-BCA893FA3F3E@gmail.com> References: <202004290844.03T8ihOm008139@gndrsh.dnsmgr.net> To: Luca Muscariello X-Mailer: Apple Mail (2.3445.9.1) Subject: Re: [Bloat] [tsvwg] my backlogged comments on the ECT(1) interim call 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: Wed, 29 Apr 2020 09:46:23 -0000 > On 29 Apr, 2020, at 12:25 pm, Luca Muscariello = wrote: >=20 > BTW, I hope I made the point about incentives to cheat, and the risks > for unresponsive traffic for L4S when using ECT(1) as a trusted input. One scenario that I think hasn't been highlighted yet, is the case of a = transport which implements 1/p congestion control through CE, but marks = itself as a "classic" transport. We don't even have to imagine such a = thing; it already exists as DCTCP, so is trivial for a bad (or merely = ignorant) actor to implement. Such a flow would squeeze out other traffic that correctly responds to = CE with MD, and would not be "caught" by queue protection logic designed = to protect the latency of the LL queue (as that has no effect on traffic = in the classic queue). It would only be corralled by an AQM which can = act to isolate the effects of one flow on others; in this case AF would = suffice, but FQ would also work. This hazard already exists today. However, the L4S proposal = "legitimises" the use of 1/p congestion control using CE, and the = subtlety that marking such traffic with a specific classifier is = required for effective congestion control is likely to be lost on people = focused entirely on their own throughput, as much of the Internet still = is. Using ECT(1) as an output from the network avoids this new hazard, by = making it clear that 1/p CC behaviour is only acceptable on signals that = unambiguously originate from an AQM which expects and can handle it. = The SCE proposal also inserts AF or FQ protection at these nodes, which = serves as a prophylactic against the likes of DCTCP being used = inappropriately on the Internet. - Jonathan Morton=