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Re: SUMMARY - 95th percentile calculation
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. On 2/27/06, Jo Rhett <email@example.com> wrote: > > 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 > asked all your uplinks you'd get wildly different answers. Averages or max > 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. > > -- > Jo Rhett > senior geek > SVcolo : Silicon Valley Colocation > -- ---- Thanks; Bill Note that this isn't my regular email account - It's still experimental so far. And Google probably logs and indexes everything you send it.