From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peteris Krumins Date: Mon, 03 Nov 2003 11:34:16 +0000 Subject: Re[2]: [LARTC] (simplified) Rate precision Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lartc@vger.kernel.org Monday, November 3, 2003, 2:37:26 AM, you wrote: AK> Am Saturday 01 November 2003 21:32 schrieb Peteris Krumins: >> i wrote a few days ago but did not receive any answers. AK> I did not receive/read this mail. That one was about limits and data precision. >> The example above should shape the speed to 2mbit (2048kbit) >> but unfortunately the real speed is only 1920kbit.. AK> How exactly do you measure the 'real speed'? The difference sounds much like AK> overhead of some sort that you're not accounting properly. For example, when AK> using scp to copy files over the line, it would be normal to have lower AK> transfer rates than the actual line speed, because there's some kind of AK> handshake/encryption overhead with every package sent. Via ftp. If I perform the tests using tbf attached to a class then the rate is precise. For example, if I measure rate of 256kbit using sfq and then tbf, sfq is always wrong at (actual_rate/rate_set) 240kbit/256kbit = 0,9375 = 6,25% 1920kbit/2048kbit = 0,9375 = 6,25% I performed several tests at different data rates and the innacuracy of 6,25 percent always remain. P.Krumins _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/