From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.21]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 717FB21F26A for ; Sun, 10 May 2015 23:50:15 -0700 (PDT) Received: from u-089-csam313b.am5.uni-tuebingen.de ([134.2.89.14]) by mail.gmx.com (mrgmx101) with ESMTPSA (Nemesis) id 0LfXmv-1ZXw6u1f8j-00p663; Mon, 11 May 2015 08:50:13 +0200 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) From: Sebastian Moeller In-Reply-To: <554F9594.60808@gmail.com> Date: Mon, 11 May 2015 08:50:12 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <554F64E1.6000609@gmail.com> <554F9594.60808@gmail.com> To: Alan Jenkins X-Mailer: Apple Mail (2.1878.6) X-Provags-ID: V03:K0:aXKG8yEERB0y1Z1mdcqHyfe/Cz15WyNhm2k01bYZdrHaJl3OfE7 DlPCEQ68HVxiU2PeLai2appOjZWz1eSlkprg1UvajMhuJxoMRfVWVhcPB6X9Ua6bHhP3S5L ncROIy0VTmzITEgYM4BAbTJinhSLF/CsFN7UjVr3Gz6r0/6ppM7oHG+0uyVANCaqfWbRoqL 1yzb6UPOjTwFJx5RKOJZg== X-UI-Out-Filterresults: notjunk:1; Cc: cake@lists.bufferbloat.net Subject: Re: [Cake] openwrt build with latest cake and other qdiscs X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 May 2015 06:50:45 -0000 Hi Alan, On May 10, 2015, at 19:29 , Alan Jenkins = wrote: > Hi again >=20 > I tested Dave's build of cake on wndr3800. (Didn't try specifying = cake2/cake3; I'm guessing tc cake means cake3 on there). "atm" = adjustment worked fine on my adsl. I can't distinguish it from = sqm-scripts with the same configuration. >=20 > SQM seems to win from having "overhead 40", which I can't configure in = cake. As expected, specifying the overhead is quite important for ATM = links, since it shifts the cell padding around (worst case without = overhead accounting is to drag in an 47of48 byte payload cell that the = accounting did not expect, causing almost 50% unaccounted overhead for = small packets, no shaper is going to be happy with such precision ;) >=20 > [table snipped as it did not survive my mailer...] > IMO it wouldn't hurt for 'tc atm', 'tc adsl', and everything else to = default to 'overhead 44'. (The highest overhead Seb reported; the = original worst case overhead[1] plus a vlan header for IPTV). Actually there old worst case was 44, with added VLAN tagging = this would end up at 48 bytes, but that would also include the ethernet = frame check sequence, which I have never seen used over ATM in the real = world (which sounds quite weird, without the FCS the payload is not = checked for bit errors anymore, so we relay on a) the atm checksums and = b) that neither the ethernet to ATM nor the ATM to ethernet repackaging = introduces bit errors)=85 (but I do not claim that I have seen that = much). Also I wonder what about double VLAN tagging as is sometimes used = bit bitstream access, no idea where the 2nd VLAN gets terminated, one = would hope way before the DSL link, but certainty would be nice. I would = humbly suggest that we should just get a numerical option for cake to = specify the overhead... Best Regards Sebastian >=20 > Alan >=20 > [1] http://ace-host.stuart.id.au/russell/files/tc/tc-atm/#usage > _______________________________________________ > Cake mailing list > Cake@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cake