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SFP:1102; SCL:1; SRVR:AM4PR07MB3137; H:AM4PR07MB3459.eurprd07.prod.outlook.com; FPR:; SPF:None; LANG:en; PTR:InfoNoRecords; MX:1; A:0; received-spf: None (protection.outlook.com: nokia-bell-labs.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: 7FGWz5za/lxKaq9cu6s1TfUvpUrnbM4pMf/e4lKaZF32ZxvMxpfwEFc5pZFqCJ1UN4eN7tDNbdadBPJ+F12IfOECh2BnyH1cCqGLxYl7KAccI2+BZhn+HGp0jSNqypPsPjbnn6XM4Kz3Cp5bAkkd+HQCMtOMIuhDj9VTOR5em6x6NY1XzNyRSoZTqq9FXI/6mq1QQ+gy3wfRWUYYe5F9Tq4DxncBB9bcRl+zsAvDFcwYdljHTBpYx8u6DgBP+eAhvCcFh3rl9Zs4DgdjObxHD4wcgbv39EVvTE+dUOrh15m53a+Yd1yM0UZnmYUZE7nybQK7Vidc+R6qbPsa+forUggmeRWebHqxj907J7S5xhrMVnY13R6PY05ekp+qQM5+vHHFb4kx2GmELBuuUg9NAXoeSlqC95eZmgqYyYX7mV0= Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nokia-bell-labs.com X-MS-Exchange-CrossTenant-Network-Message-Id: 7cbfe38e-c8a8-45eb-1525-08d700858ca5 X-MS-Exchange-CrossTenant-originalarrivaltime: 04 Jul 2019 13:43:08.5574 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 5d471751-9675-428d-917b-70f44f9630b0 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: koen.de_schepper@nokia-bell-labs.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM4PR07MB3137 X-Mailman-Approved-At: Mon, 08 Jul 2019 09:38:39 -0400 Subject: Re: [Ecn-sane] [tsvwg] Comments on L4S drafts X-BeenThere: ecn-sane@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion of explicit congestion notification's impact on the Internet List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Jul 2019 13:43:10 -0000 Jonathan, >> 2: DualQ can be defeated by an adversary, destroying its ability to isol= ate L4S traffic. Not correct. DualQ works not different than any (single q) FIFO, which can = be defeated by non-responsive traffic. It even does not matter what type of traffic the adversary is (L4S or Class= ic drop/mark), as the adversary will push away the responsive traffic only = by the congestion signal it invokes in the AQM (drop or classic or L4S mark= ing). The switch to drop for all traffic from 25% onwards avoids that ECN f= lows get a benefit under overload caused by non-responsive flows. This mech= anism protects also Classic ECN single Q AQMs, as defined in the ECN RFCs. So conclusion: a DualQ works exactly the same as any other single Q AQM s= upporting ECN !! Try it, and you'll see... Koen. -----Original Message----- From: tsvwg On Behalf Of Jonathan Morton Sent: Thursday, July 4, 2019 2:24 PM To: Bob Briscoe Cc: ecn-sane@lists.bufferbloat.net; tsvwg@ietf.org Subject: Re: [tsvwg] [Ecn-sane] Comments on L4S drafts > On 4 Jul, 2019, at 2:54 pm, Bob Briscoe wrote: >=20 > The phrase "relative to a FIFO" is important. In a FIFO, it is of course = possible for flows to take more throughput than others. We see that as a fe= ature of the Internet not a bug. But we accept that some might disagree... Chalk me up as among those who consider "no worse than a FIFO" to not be ve= ry reassuring. As is well documented and even admitted in L4S drafts, L4S = flows tend to squash "classic" flows in a FIFO. So the difficulty here is twofold: 1: DualQ or FQ is needed to make L4S coexist with existing traffic, and 2: DualQ can be defeated by an adversary, destroying its ability to isolate= L4S traffic. I'll read your reply to Jake when it arrives. - Jonathan Morton