Re: [nsp] bit rate accuracy?

From: scott w (scott@digisle.net)
Date: Tue Nov 13 2001 - 14:52:48 EST


On Tue, 13 Nov 2001, Deepak Jain wrote:

>
> If I remember correctly, Cisco uses some kind of decaying average algorithm
> to report bit rate/second on interfaces.

5 minute exponentially weighted average:

new avg = (avg - interval) e^(-t/c) + interval

where t = 5 sec c = 5 min

e^(-t/c) = e^(-5/300) = .983

avg = previous new avg

interval = value of the current sample (such as: load, reliability, or
packets per sec)

Working Equation: .98(avg - interval) + interval

scott



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