Re[2]: [LARTC] (simplified) Rate precision

Re[2]: [LARTC] (simplified) Rate precision

[Peteris Krumins]

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

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