# SUMMARY - 95th percentile calculation

My thesis that I wanted to prove or disprove was that the market seems to
have standardized how they calculate 95th percentile. Years ago if you
values over days, weeks or months. Rarely would two answers jive.

But it appeared that most providers are now using 5 minute averages as the
value input over a billing month for 95th% calculation. Was this truly
standard now?

The answer is yes. All of our paid transit links use 5 minute averages,
and all but one of the replies to my query here did too.

8 providers use 5 minute averages of 30 second counter checks as the base
value calculated over the billing month.

2 providers use 5 minute averages of 1 minute counter checks as the base
value calculated over the billing month.

8 providers use 5 minute implicit averages (a single counter check) as the
base value calculated over the billing month.*

1 provider uses the maximum value found in 5 minutes of 1 minute counter
checks for the 5 minute value, and calculates that over the billing month.

1 provider uses 5 minute implicit averages (a single counter check) but
calculates that over a fixed 30 day month. (I didn't ask what they did with
the extra days)

At first glance my tendancy would be to say that 20 answers is hardly
authoritative, but the 30 second counters (first listed) comprise 6 of the
top US bit movers, and 2 of the largest bit pushers so I'm satisfied with
the results for my purposes.

* One very large bit mover that I know uses 32 bit counters claimed to only
be checking every 5 minutes. We're pushing enough to them to rotate that
counter in that interval, so I actually disbelieve this answer but I'm
reporting it as they said it.

[...]

* One very large bit mover that I know uses 32 bit counters claimed to
only be checking every 5 minutes. We're pushing enough to them to rotate
that counter in that interval, so I actually disbelieve this answer but
I'm reporting it as they said it.

A wrapped counter appears to be affecting our electricity metering and
billing. While the measurement of kWh is probably in the right ballpark for
somebody our size, they also reckon our peak consumption is about 1kW.

Since the bill usually has a pound sign followed by a telephone number, I've
toyed with the idea of disputing the bill on the basis we couldn't possibly
use that much power with just a 1kW load, but we'll pay the 40 quid for one
month of 1kW

I'm not operationally involved at AT&T, but what I've been told is that we track
5-minute samples in both directions, and do the 95th% calculation on
all the samples,
as opposed to tracking 95% of inbound-only or outbound-only or
max(in,out) samples.