From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-x230.google.com (mail-lb0-x230.google.com [IPv6:2a00:1450:4010:c04::230]) (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 ACA0F21FCA8; Thu, 30 Jul 2015 13:29:47 -0700 (PDT) Received: by lblf12 with SMTP id f12so34461824lbl.2; Thu, 30 Jul 2015 13:29:45 -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=cA0exZOmlhSG9rPAs+OqUeJZnIrycxw9UenZ17QPVcE=; b=A/5SSloX+iZiDaitQXTQ0wAGHjiNyRMDGRe7X5+H0cJyPFl+wnsPfKOSlWBMvQV+3I CRzPg7N9I962liWFxNpy3tLreWVVh0HGqRrSjbgKwDylIZ/AMp0r6OnY0E1JQyYtvdjC GoxCKQqZ9WO3kGCeUG6rqbcLEdzKF8DZRUOm5mSa4EjKXQYaN6fpJwYkzx6iVL0YvmT7 +7XRl2SvypUtXyXJQThhuKwZnx64ybz7Gj/Id/WHKF1nvxr7A+w4DFZbi/LngMRkFtSK Pd6qh+wBjZTjMuiKrWuh7meQbNFeFiJrG83TFHoG8q684fc4sChr2D685KLceA+0S4Sh rclA== X-Received: by 10.152.28.73 with SMTP id z9mr46124656lag.93.1438288184877; Thu, 30 Jul 2015 13:29:44 -0700 (PDT) Received: from bass.home.chromatix.fi (178-55-11-31.bb.dnainternet.fi. [178.55.11.31]) by smtp.gmail.com with ESMTPSA id wc1sm463626lbb.44.2015.07.30.13.29.40 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 30 Jul 2015 13:29:43 -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: Thu, 30 Jul 2015 23:29:36 +0300 Content-Transfer-Encoding: quoted-printable Message-Id: <356F5FEE-9FBD-4FF9-AC17-86A642D918A4@gmail.com> References: To: Dave Taht X-Mailer: Apple Mail (2.2102) Cc: make-wifi-fast@lists.bufferbloat.net, "cerowrt-devel@lists.bufferbloat.net" Subject: Re: [Make-wifi-fast] [Cerowrt-devel] [tsvwg] Comments on draft-szigeti-tsvwg-ieee-802-11e X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Jul 2015 20:30:16 -0000 > https://datatracker.ietf.org/doc/draft-szigeti-tsvwg-ieee-802-11e/ > On the topic of the actual mappings.... Here=E2=80=99s a handy comparison table to show how the draft, CJ=E2=80=99= s suggestions, and cake=E2=80=99s current implementation map DSCPs to = traffic classes: DSCP | SZ | CJ | Cake --------------------- CS7 | XX | VO | VO CS6 | ?? | VO | VO EF | VO | VO | VO VA | VO | VO | VO CS5 | VI | VO | VO AF4x | VI | VI | VI CS4 | VI | VI | VO AF3x | VI | BE | VI CS3 | VI | BE | VI AF2x | BE | BE | VI CS2 | BE | BE | VI AF1x | BK | BE | BE DF | BE | BE | BE CS1 | BK | BK | BK TOS4 | BE | BE | VI TOS2 | BE | BE | BE TOS1 | BE | BE | VI Interesting to note that cake puts a lot more traffic in =E2=80=9Chigh=E2=80= =9D classes than either of these suggestions. I also note that cake = does invert CS4 vs AF4x in a way that CJ doesn=E2=80=99t like - but = perhaps this is mitigated by the fact that cake thresholds VI at three = times the bandwidth as VO, which I think is appropriate since video = consumes more bandwidth than voice (or games) traffic. None of these suggestions make any practical distinction between the = =E2=80=9Cdrop probability=E2=80=9D divisions within the AFxx classes - = even though in some cases they are mapped to distinct UP values, these = always fall into the same major class. I suppose that distinction would = be better left to an AQM algorithm that was aware of them, which cake is = not since I can=E2=80=99t immediately see a way to make Codel respond = reasonably to it. The draft doesn=E2=80=99t address the =E2=80=9Clegacy=E2=80=9D = codepoints associated with the old TOS bits, but cake does, so I = extended the table accordingly. I couldn=E2=80=99t quite decipher Sebastian=E2=80=99s suggestions into = table form, so I omitted those. The major =E2=80=9Cdangerous=E2=80=9D feature I see in the draft is the = treatment of CS6 and CS7 traffic - long on =E2=80=9Cdrop or remark=E2=80=9D= and short on =E2=80=9Cif you must, just stick it in VO". CS6 in = particular is used by common NTP implementations, and for good reason. = As far as I=E2=80=99m concerned, equipment should *not* remark or drop = traffic by default based solely on its DSCP. Indeed, equipment should = probably assume they are not acting as the edge of a network domain = unless specifically configured otherwise. - Jonathan Morton