From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [PATCH 0/2] NET: Accurate packet scheduling for ATM/ADSL Date: Tue, 20 Jun 2006 09:33:25 +0200 Message-ID: <1150788805.3480.31.camel@localhost.localdomain> References: <1150278004.26181.35.camel@localhost.localdomain> <20060620053536.GA10311@tuatara.stupidest.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-3gsW3VxIo49i4V0m7YvI" Cc: netdev , russell-tcatm@stuart.id.au Return-path: Received: from ex001a.cxnet.dk ([195.135.216.13]:11121 "EHLO comxexch01.comx.local") by vger.kernel.org with ESMTP id S965127AbWFTHd1 (ORCPT ); Tue, 20 Jun 2006 03:33:27 -0400 To: Chris Wedgwood In-Reply-To: <20060620053536.GA10311@tuatara.stupidest.org> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --=-3gsW3VxIo49i4V0m7YvI Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Mon, 2006-06-19 at 22:35 -0700, Chris Wedgwood wrote: > On Wed, Jun 14, 2006 at 11:40:04AM +0200, Jesper Dangaard Brouer wrote: >=20 > > The Linux traffic's control engine inaccurately calculates > > transmission times for packets sent over ADSL links. For some > > packet sizes the error rises to over 50%. This occurs because ADSL > > uses ATM as its link layer transport, and ATM transmits packets in > > fixed sized 53 byte cells. >=20 > What if AAL5 is used? The cell-alignment math is going to be wrong > there surely? Actually it _is_ AAL5 which is accounted for. See Chapter 5 "ADSL link layer overhead" (page 48-54). http://www.adsl-optimizer.dk/thesis/main_final_hyper.pdf --=20 Med venlig hilsen / Best regards Jesper Brouer ComX Networks A/S Linux Network developer Cand. Scient Datalog / MSc. Author of http://adsl-optimizer.dk --=-3gsW3VxIo49i4V0m7YvI Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQBEl6TFwuVH+NB3fZkRAvrlAJ9Is5CDyMSjd/bcC77e7UNPG1vEhACfdIDc rclEWoWa2fiePYrPVONrOIk= =nXhD -----END PGP SIGNATURE----- --=-3gsW3VxIo49i4V0m7YvI--