Re: 95th Percentile again!

["Richard A. Steenbergen" <ras () e-gerbil net>]

On Sun, 3 Jun 2001, Greg A. Woods wrote:

> [ On Saturday, June 2, 2001 at 23:17:48 (-0400), Richard A. Steenbergen wrote: ]
> > Subject: Re: 95th Percentile again (was RE: C&W Peering Problem?)
> >
> > No matter how you stack it, if you miss a rate sample there is no way to
> > go back and get the data again. You either discard it and lose the ability
> > to bill the customer for it (which demands high availability polling
> > systems), or you make up a number and hope the customer doesn't notice.
> > Volume polling does not suffer from this problem.
>
> What the heck are you talking about?  Only a totally amateur design
> would fail to account for the possibility of a dropped sample (or any
> other of several critical issues faced by anyone using counters to
> determine the average or Nth percentile rates).
>
> In fact the accounting for bulk throughput per period is done in
> almost exactly the same as any rate-based accounting too (only the
> counter sample time might differ, but of course you can't stretch it
> too far for the former case lest you risk an undetectable wrap-around
> event).

Actually I was refering to the more common methods of rate based
measurement, MRTG. The names of the providers who use this will be
omitted. :P

-- 
Richard A Steenbergen <ras () e-gerbil net>       http://www.e-gerbil.net/ras
PGP Key ID: 0x138EA177  (67 29 D7 BC E8 18 3E DA  B2 46 B3 D8 14 36 FE B6)