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Re: What does 95th %tile mean?


From: Arnold Nipper <arnold () nipper de>
Date: Fri, 20 Apr 2001 15:05:24 +0200


On Thu, Apr 19, 2001 at 05:18:02PM -0700, David Schwartz wrote:


      I've looked at other ways and can't find any better. Billing based upon
NetFlow, for example, is still statistical sampling since NetFlow loses a
percentage of flows. For example, one of my VIP2-50's says:


So did you calculate, how much you are losing. It's less than 1% of a 1% of
all flows. That means you catch up more than 99.99% of all flows. Not that bad.
Furthermore NetFlow gives you the ability to offer value added (billing)
services to your customers. For example ...

  368351628 flows exported in 12278484 udp datagrams
  33838 flows failed due to lack of export packet
  269989 export packets were dropped enqueuing for the RP
  108825 export packets were dropped due to IPC rate limiting

      Billing based upon total bytes transferred tends to create similar
problems. Do you bill based upon bytes transferred per day? Per month? If
so, it's still statistical sampling if you have some amount of 'paid
bandwidth'.

      And you can't collect this data from interfaces because interface rates
include local traffic, which (for example) grossly overbills customers with
newsfeeds.


... you may easily deduct News traffic from being billed. BTW: tell me how
do you exclude News Traffic if you count the 95th %ile?

Billing based upon total bytes transferred is IMHO verfy fair and attractive
from the point of a customer's view and tends to be a nightmare from an ISP's
pespective especially if you don't just count bytes but are looking at the
IP-addresses involved.

Maybe a mixture of byte-counting and portspeed would give a fair billing
model. BTW that's also the model you pay power for in Germany.

      DS

Arnold
-- 
Arnold Nipper / nIPper consulting          mailto:arnold () nipper de
Heilbronner Str. 34b                       Phone:  +49 700 NIPPER DE
D-76131 Karlsruhe                          Mobile: +49 172 2650958
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