A question of stats..
horvitz at websecure.net
Sun Jun 8 13:07:43 UTC 1997
Here is something which has been troubling my mind lately.
The basic question is, how do I turn an in and an out into
an aggregate? Here is a scenario: I measure usage on a
customer's T1 at my router port. Every 5 minutes a sample
the port and figure the average bps both in and out for the
last five minutes. Now, I want to make a number that
represents the aggregate usage across that port but, I cannot
simply add the two ins and outs (as I am doing now) because
they were both averages over a period of time. Doing this
produces some strange effects which can show nice trends but
also lies about the real usage. Perhaps I simply lack the
math experience to do this correctly but I can't see a good
way to do it.
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