From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-x235.google.com (mail-lb0-x235.google.com [IPv6:2a00:1450:4010:c04::235]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id C902221F41E for ; Mon, 20 Jul 2015 00:52:05 -0700 (PDT) Received: by lbbyj8 with SMTP id yj8so90404496lbb.0 for ; Mon, 20 Jul 2015 00:52:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=content-type:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=NVI+bh/7aVmUqA/u4YU3SFEBlEq4LVrYdSCmdbdZGRo=; b=puK00I1D53+iAhUxXcosxx7ypyky1TtOuiHAA8S1KukTfueClvpehFZ0K8pnoyewE9 YBlv7HXqOvSsmGzB5MDvfL9W+QbdjbCiA31Wz22u0o09/HbVL06P6RzzD5yfmzZ2u66c gdaebsTbMwp9g1jnPistKuITSC69qkROXqhxL7259INibRqMpCj/Rcqaa0M3pb1IJsJd 1L6NY9w8CMiYyYJNLvH5h1HFgi64FAIqrrh6uAUPnYKzCn92e85s3yKEwDPJcLmgx6Ws MbyFs/nUBqynwLownUw/xz3pJe/B/zE2THjM8uxDIoNiTQk+xXE/yocY3TEF1SDpCJW6 rcSQ== X-Received: by 10.112.78.105 with SMTP id a9mr26477458lbx.70.1437378722952; Mon, 20 Jul 2015 00:52:02 -0700 (PDT) Received: from bass.home.chromatix.fi (188-67-145-250.bb.dnainternet.fi. [188.67.145.250]) by smtp.gmail.com with ESMTPSA id p5sm1104373lba.36.2015.07.20.00.52.01 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 20 Jul 2015 00:52:02 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2102\)) From: Jonathan Morton In-Reply-To: Date: Mon, 20 Jul 2015 10:51:58 +0300 Content-Transfer-Encoding: quoted-printable Message-Id: <7A5017C0-A403-46CD-AAF5-E89F4B4789B0@gmail.com> References: <33363.1437323022@ccr.org> To: Mikael Abrahamsson X-Mailer: Apple Mail (2.2102) Cc: cerowrt-devel@lists.bufferbloat.net Subject: Re: [Cerowrt-devel] Cerowrt-devel Digest, Vol 44, Issue 24 X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Jul 2015 07:52:34 -0000 > On 20 Jul, 2015, at 10:17, Mikael Abrahamsson = wrote: >=20 > On Sun, 19 Jul 2015, Jonathan Morton wrote: >=20 >> In the current version, a bandwidth threshold is used instead. If the = traffic in the class remains below the threshold, then they get the (non = strict) priority requested. If it strays above, the priority is demoted = below other classes instead. In the absence of competing traffic, any = class can use the full available bandwidth, but there's always room for = other classes to start up. >=20 > I had an idea of using DSCP 000xx0 and have a BE+, BE and BE-. BE+ = would be scheduled to send packets twice as often as BE, and BE- would = be 1/10th of (BE+ BE). >=20 > I keep getting pushback from the DSCP authors that he BE- idea = wouldn't be a problem (and they agree that it makes sense for a = scavenger class), but that my idea of BE+ should be something else, for = instance AFxy. I don't believe anything that isn't 000xxx will ever get = widely deployed for Internet use, and there should be no strict priority = but just a slight preference for scheduling packets with the BE+ code = point, exactly to make DDOS less of an impact. >=20 > What is your opinion on this concept? I could add support for, say, DSCP 000110 mapping to the Background = class with one line of code in Cake; that would give it the same = treatment as CS1 currently gets. The legacy TOS codepoints 000001 and = 000100 (Low Delay and High Reliability) already map to the Video class; = I=E2=80=99ve deliberately left 000010 (High Throughput) in the Best = Effort class. In effect, that would give very similar behaviour to what you suggest. = Assuming the link is saturated with all three classes of traffic, = three-quarters of the bandwidth would be dedicated to the Video class, = three-quarters of the remainder would be Best Effort, and just = one-sixteenth would be Background. Additionally, there is already *some* traffic routinely using CS6 (eg. = NTP) and EF codepoints, which I think are relatively well-established as = =E2=80=9Clow throughput, low latency=E2=80=9D indicators. Those both go = in the Voice class in Cake, which is thresholded at one-quarter of the = link. If all four classes are saturating the link, that would just = reduce the Video class=E2=80=99s share to one-half instead of = three-quarters, leaving the remaining two classes alone. More generally, using unconditional strict priority for anything is a = Very Bad Idea - as noted, it=E2=80=99s just too easy to abuse. - Jonathan Morton