What does 95th %tile mean?

Sean Morrison seanm at dnai.com
Thu Apr 19 14:42:26 UTC 2001

Hi Alex,

  I work as an engineer in the product development group at Telseon.  I'm
curious about what feedback you get, especially what method the other
providers you list use to calculate the 95th percentile.

  For what it's worth, I agree with you and the method you mention.  I'd
be surprised if others in that league are doing it differently.

  Telseon doesn't bill using the 95th percentile method though.  We let
the customer adjust their bandwidth on the fly and bill them for what they
provision.  Since they can reprovision via a web interface they can jump
around (5 megs one day 500 megs the next).

Thanks in advance for any info you garner.

-Sean Morrison

On Thu, 19 Apr 2001, Alex Rubenstein wrote:

> I've gotten myself into an argument with a provider about the definition of
> 'industry-standard 95th percentile method.'
> To me, this means the following:
> a) take the number of bytes xfered over a 5 minute period, and determine
> rate for both the inbound and outbound. Store this in your favorite
> data-store.
> b) at billing time, presumably on the first of the month or some other
> monthly increment, take all the samples, sort them from greatest to least,
> hacking off the top 5% of samples. Actually, this is done twice, once for
> inbound, once for outbound. Then, take the higher of those two, and multiply
> it by your favorite $ multiple (ie, $500 per megabit per second, or $1 per
> kilobit per second, etc).
> I think that most people agree with the above; the issue we are running into
> is one rogue provider who is billing this at in + out, not the greater of in
> or out.
> How is everyone else doing it? Specifically, larger folks (UU, Sprint, CW,
> Exodus/FGC, GX, Qwest, L3)
> Thanks!

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