What does 95th %tile mean?

Arnold Nipper arnold at nipper.de
Fri Apr 20 13:05:24 UTC 2001

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 Nipper / nIPper consulting          mailto:arnold at nipper.de
Heilbronner Str. 34b                       Phone:  +49 700 NIPPER DE
D-76131 Karlsruhe                          Mobile: +49 172 2650958
Germany                                    Fax:    +49 180 505255469743

More information about the NANOG mailing list