What does 95th %tile mean?

Fri Apr 20 15:38:55 UTC 2001

On Fri, 20 Apr 2001, Alex Rubenstein wrote:

> > ... you may easily deduct News traffic from being billed. BTW: tell me how
> > do you exclude News Traffic if you count the 95th %ile?
> 
> Why should you? packets are packets; does your upstream provider charge
> you less for news? Are you magically capable of moving news across your
> own network cheaper than web traffic?

Yes, they pay less for news then other traffic (possibly including web).
Why?

Because they suck N packets of news from their providers news server, but
can then provide customers*N worth of news packets out to their
subscribers.

I think in areas of heavy byte-level billing, some providers have been
known to sell connectivity at the cost of local-loop + byte usage and
required their users to use a Squid WWW cache, making their profit off of
the savings caused by the cache.

> > 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.
> 
> Agreed.

If fair = reflectes the ISPs costs of operation (which is the only useful
meaning of fair I can come up with here):

It's not fair unless the load is equally distributed (i.e. uncorrelated
between many customers). 

In North America, ISPs pay for pipes not bytes. The pipes are provisioned
for peak usage, not average. Like electrical power, if you fail at
providing for peak load you cause very poor service.