From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x22d.google.com (mail-lf0-x22d.google.com [IPv6:2a00:1450:4010:c07::22d]) (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 8C11F3B2A0 for ; Thu, 2 Jun 2016 10:49:08 -0400 (EDT) Received: by mail-lf0-x22d.google.com with SMTP id w16so35622092lfd.2 for ; Thu, 02 Jun 2016 07:49:08 -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=+/k9bd0AyO3yQO2xhbvnsz7xRcEE33izx0g4msma3FI=; b=fJAo0uqTmm+cE/xERqkj1djsi9lzurm+c64bukHYjCG6ZpjB+pglNBx34YMhVJHvsZ ejtuQX+DeI9A7o3gDPvw8Fh0W+GHhk5ZMzmsohrjT+39ZGxFLGKmxK7pf+odMC46OaQF JCarasKVGKfaOyk4vUQHbNcXCGrr0Q0kwM+6LjEKlQNxJMZmguVKdwfMBgEOlE/B9wuX wuK6TRzsUy9lw6oZAl+ZeQcmfLJCGXC4B89LTje5/tIPdUg4DF7QTCTz1qxhVP8WhQ1j P6QdaSHJx7eA5yyu/x7QImxsXOQzuSHhQ8BmTSGY1rAo0/BoABESNDsYTMOYasqjGSwT kfrw== 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=+/k9bd0AyO3yQO2xhbvnsz7xRcEE33izx0g4msma3FI=; b=fghNfaK4NW7e+8k6pc4/g7Iju8OVoYLSVGNZiAdvKWjvT1LGsihtVhzo+Shneu5jAr 0RkSBJxRFXwlrG4L5pX+qsTKJEUzu77LU6xO/Y+x+brN5pEYfSFyu/p2Hs5S1Gulm/ie pfCMz8PR8UZ8zdFf/btLoD5Kko35uznyQSRZzikhovY0AuVKAsMkk+Jw7KwS+pTcmjC+ jP/cLABBbnd8YMeJza7QuJK2LNfyl657sh9Ymaw3E7nBIISvmzJbrJhORQnseRzIiUoZ bgOU4d4T4nCdDMSY4EAci3ycZATSPNK8YMwxAe4pN2IB1rPoxDyQ9+C2hK8IAJaiuKkD n0ZQ== X-Gm-Message-State: ALyK8tIBtxV6IPoNT0s7inaRHzkKDlGt2asKaJYT50wXHhu1neRhl/l/+dlI4rFId+hXkQ== X-Received: by 10.46.0.134 with SMTP id e6mr4002731lji.37.1464878947407; Thu, 02 Jun 2016 07:49:07 -0700 (PDT) Received: from [192.168.100.11] (37-33-56-85.bb.dnainternet.fi. [37.33.56.85]) by smtp.gmail.com with ESMTPSA id r5sm84925lbb.14.2016.06.02.07.49.06 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 02 Jun 2016 07:49:06 -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: <87a8j3fyxc.fsf@toke.dk> Date: Thu, 2 Jun 2016 17:49:04 +0300 Cc: Kevin Darbyshire-Bryant , cake@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: References: <574FFE52.1040501@darbyshire-bryant.me.uk> <2A84540D-AA30-4BD0-AF9A-5510EA00B7E8@gmail.com> <87a8j3fyxc.fsf@toke.dk> To: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= X-Mailer: Apple Mail (2.3124) Subject: Re: [Cake] cake/tc - removal of atm/ptm/ethernet specific overhead keywords X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 Jun 2016 14:49:08 -0000 >> It would be nice if LuCI could infer information about the likely >> overheads from the rest of the configuration, and apply (or suggest & >> default) the correct keywords in sqm-scripts. That would make the >> feature much more widely used. >=20 > We can probably do this for the most common cases, but am not so sure > it's unambiguous when to pick what. If someone can supply a couple of > examples of configuration where we are fairly certain we know what to > pick, I can look into how that can be inferred in luci=E2=80=A6 The most obvious cases are where there is an ADSL or VDSL modem built = into the router, as there is on my Buffalo WBMR (though I don=E2=80=99t = currently have a working ADSL line to demonstrate a live example). SQM = on the WAN-facing interfaces which (directly or indirectly) use that = modem should then infer the PPP and ATM modes from the modem=E2=80=99s = configuration, which I know is visible to LuCI in some form. It=E2=80=99s slightly less obvious what to do with a standalone router, = where there is a separate modem handling the PPP endpoint, thus the WAN = interface appears in all respects to be Ethernet. For this case, an = easy way of setting the =E2=80=9Cconservative=E2=80=9D, =E2=80=9Cbridged-p= tm" or =E2=80=9Cpppoe-ptm=E2=80=9D keywords should do the trick, perhaps = with =E2=80=9Cconservative=E2=80=9D being the sane default. The PTM = keywords are better suited to VDSL installations. I suspect cable and = cell modems may work best *without* overhead compensation. As for the =E2=80=9Cconservative=E2=80=9D keyword, it assumes ATM = encapsulation and exactly one ATM cell of inner encapsulation overhead, = the latter exceeding all known combinations of inner encapsulation used = in practice (except for bizarre cases involving IP-in-IP tunnelling). = It=E2=80=99s intended to be a reasonable default where it is known or = suspected that encapsulation is in use, but no specifics are known. Sebastian seems to have more detailed information about what = encapsulation combinations are actually in use in Germany, and can = doubtless advise on how these show up in LuCI on an ADSL router. - Jonathan Morton