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-AES128-SHA (128/128 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 7A11521F0BD for ; Fri, 23 Aug 2013 12:49:30 -0700 (PDT) Received: from hms-beagle-2.home.lan ([79.229.225.62]) by mail.gmx.com (mrgmx102) with ESMTPSA (Nemesis) id 0M3u86-1W38TS0hP8-00rZOG for ; Fri, 23 Aug 2013 21:49:28 +0200 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 6.5 \(1508\)) From: Sebastian Moeller In-Reply-To: <6665470B-0F21-4383-93F6-3D5E87DDE5F3@imap.cc> Date: Fri, 23 Aug 2013 21:49:29 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <56B261F1-2277-457C-9A38-FAB89818288F@gmx.de> <2148E2EF-A119-4499-BAC1-7E647C53F077@gmx.de> <03951E31-8F11-4FB8-9558-29EAAE3DAE4D@gmx.de> <20130823092702.3171b5fd@redhat.com> <20130823131653.6aa3498f@redhat.com> <2D3FE3C2-AD17-4CDF-8DC3-D807B361EE66@gmx.de> <6665470B-0F21-4383-93F6-3D5E87DDE5F3@imap.cc> To: Fred Stratton X-Mailer: Apple Mail (2.1508) X-Provags-ID: V03:K0:9sw751A0vptyDa1yGHOElqvAqb+qINPZeUiKox3NkNfkKqbLdRC bJIwYYIUa/Fx9rFNLOWOnyWnJlZfCJI1B5Rv/6JxDzoxlFhO70vM4e2uecdPgAu2WgKH09K QBgf9OIHtiMKtPfgRr/AbBGI4vh71vJSDFTdxeu/JQKsvwY0RTDQDW0smKDRxb5mV/w9lhs j0+66Ij7kiQytbbEAJB9Q== Cc: "cerowrt-devel@lists.bufferbloat.net" Subject: Re: [Cerowrt-devel] some kernel updates 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: Fri, 23 Aug 2013 19:49:31 -0000 Hi Fred, On Aug 23, 2013, at 15:02 , Fred Stratton wrote: [snipp] >>=20 >>>=20 >>> Thus, in kernels >=3D 3.9, you would need to change/reduce your tc >>> "overhead" parameter with -14 bytes (iif you accounted encapsulated >>> Ethernet header before) >>=20 >> That is what I thought before, but my kernel spelunking made me = reconsider and switch to not subtract the 14 bytes since as I understand = it the kernel actively does not do it if stab is used. >>=20 >>>=20 >>> The "overhead" of stab can be negative, so no problem here, in an = "int" >>> for stab. >>>=20 >>>=20 >>>>> Meaning that >>>>> some ATM encap overheads simply cannot be configured correctly (as = you >>>>> need to subtract the ethernet header). >>>>=20 >>>> Yes, I see, luckily PPPoA and IPoA seem quite rare, and setting = the overhead to be larger than it actually is is relatively benign, as = it will overestimate packe size. >=20 >=20 > As a point of information, the entire UK uses PPPoA rather than PPPoE, = and some hundreds of thousands of users IPoA. Lucky you! I guess one more reason to switch cerowrt over to = stab, since PPPoA with VC/mux just adds 10 bytes of overhead, so if the = ethernet would be accounted for already that would mean overhead -4 = which HTB can not represent anyway. That said, unlike Jesper, I am not = sure that tc stab includes the ethernet header by itself currently. = Thanks for you input. [snipp] Best Sebastian