From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x230.google.com (mail-lf0-x230.google.com [IPv6:2a00:1450:4010:c07::230]) (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 2E4C43B47D for ; Wed, 20 Apr 2016 08:43:30 -0400 (EDT) Received: by mail-lf0-x230.google.com with SMTP id e190so40120018lfe.0 for ; Wed, 20 Apr 2016 05:43:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=GsRZsFPRc4dlkN4xlHQLi6g+6QePMUZLf5raUQGeeiQ=; b=ASF8cnTAUzdNJAU6nkIIRLkwLwvPDEg/6MqKSmnD7CSmR5gLKs3vkxZojfIfP/bfTR IV7sZ8MvRiQyGyGWFaBmH+vvNhJ6jn3dLqFdC/ckFOgxGi37FgHQco6YVT0bXL1bRhjh 9Yjt0VprvRIwc3l/Hcxmx4wEcI9CoQDajnY6r/0o58FzU6MShFmdk/SHBT4xn9rTmI+j 2pAyJYP1U30acFNcemhJg0bmnjb4Wlu9C4hr7eh9cCrtGO+dzY7Lpt5y90HGntlHHL9p 31T2wnau4FPojtj5ZBJDTh7LejvnbZbBUnU13coq1gpHo4hAwxINM5FVzY3uGneZbMt/ PlyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=GsRZsFPRc4dlkN4xlHQLi6g+6QePMUZLf5raUQGeeiQ=; b=YAq0pG4hCECeFvMJ38cAJj3BPbNv1XFHSRsx0LU6ORSWEhpSWrVCph2WoKwEU9bLos nav9XWJxZZpnWi4NifXnE+ca+XQy/h49aIifryEPaF6aLSXYXAkeftiTrNjzrvZ5HVL2 JzIv4hDYBALpZL/b5wtoewzO9tu/Il+5GI06Fozusv9VXyNZnIeYVSKp/V3n4LvdvATu cWWumbFLz8QMZVloOKlxq8H2DYEO0wSPe+6YOmkuGEr0Y3WMuuvK1TGReqYbBLwNPOIj H8VqoA4GJODiXMQX5le8kJPYiMn/eF8+cZTTSzNTUoEpHW8x5b3C8xvNANwThkVQGhYi sSzQ== X-Gm-Message-State: AOPr4FUP1mtke9mkbkv4lcI1tGrmrw69engV1bRjnScxBnpoMqENmKrtJ/MKwA+ciaxhbg== X-Received: by 10.25.17.99 with SMTP id g96mr9615lfi.112.1461156208821; Wed, 20 Apr 2016 05:43:28 -0700 (PDT) Received: from bass.home.chromatix.fi (37-33-67-252.bb.dnainternet.fi. [37.33.67.252]) by smtp.gmail.com with ESMTPSA id u10sm1075151lbu.13.2016.04.20.05.43.27 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 20 Apr 2016 05:43:28 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: Jonathan Morton In-Reply-To: Date: Wed, 20 Apr 2016 15:43:23 +0300 Cc: "Livingood, Jason" , bloat Content-Transfer-Encoding: quoted-printable Message-Id: References: To: jb X-Mailer: Apple Mail (2.3124) Subject: Re: [Bloat] dslreports bufferbloat tests 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, 20 Apr 2016 12:43:30 -0000 > On 20 Apr, 2016, at 09:06, jb wrote: >=20 > So this particular snap from the first 200 packets of a download there > are poor RTTs but it also picked up the IP ecn_capable flag (but not > the IP ecn congestion flag) and it picked up the TCP ece and cwr flags > on. The TCP ECE and CWR flags are always set during ECN negotiation. If = there are no CE marks subsequently, they will not appear again once the = data phase begins. You can therefore distinguish between ECN capability = of the host and the network. For a =E2=80=9Cdownload=E2=80=9D test, your sender will see ECE flags = inbound and generate CWR flags outbound *during the data phase* only if = there is an ECN aware AQM on the path at the bottleneck. It will not = see the CE marks themselves, as those are only present between the = bottleneck and the receiver. For an =E2=80=9Cupload" test, your receiver will see the inbound CE = marks from an AQM active on the bottleneck, respond to them with ECE = flags, and receive CWR flags in reply. Again, only during the data = phase. - Jonathan Morton