From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bryce Cronkite-Ratcliff Subject: Instantaneous Threshold ECN marking for DCTCP Date: Thu, 17 Dec 2015 08:13:49 -0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 To: netdev@vger.kernel.org Return-path: Received: from mail-wm0-f48.google.com ([74.125.82.48]:37002 "EHLO mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756071AbbLQQNu (ORCPT ); Thu, 17 Dec 2015 11:13:50 -0500 Received: by mail-wm0-f48.google.com with SMTP id p187so28416641wmp.0 for ; Thu, 17 Dec 2015 08:13:50 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: Hi there, I am attempting to run some experiments with DCTCP using mininet (so this is all user-level emulation -- my switch is a linux namespace using OVS). My question is on how to apply DCTCP's AQM. DCTCP's AQM just marks all packets with CE if they are received when the queue is over a threshold value of K and otherwise does not mark CE. The DCTCP papers I have seen suggest that RED can be used to achieve this: set probability to 1, burst to 1, and min and max to the same value. However, tc-red, in accordance with this paper, does not allow burst to be significantly below the minimum threshold value, so I am unable to set the parameters I would like -- in particular to set burst to 1 -- without monkey-patching tc. Is there a way to achieve this simple threshold-ECN marking AQM with tc, or another approach? Thank you!