I need an advice here. Is this usually better or worse than the actual usage.

Do you mean average?

70% billing is worse than actual usage in the sense that you usually pay more.

It's better in the sense that it gives the network provider more headroom with which to provision extra bandwdith, so that the network is _potentially_ faster.

I think...

most providers charge 95th,

every 5 mins a snap shot is taken.

then lined up from smallest to largest / the 70th highest is the charge.

Correct me if I am wrong, but the 95% rule came into affect to counter balance all the router/Internet spikes that use to occur. So it wasn't fair to bill for that traffic and they had no way to measure it, so they created the 95% rule. The 70% would mean they throw out 30% of your highest traffic, then average all remaining to provide th monthly average for billing. That would be a good deal. 30% of your traffic is thrown out.

MRTG tkaes the average of all incoming and outpoing. You need to run a perl script to calculate the 95%. Then it is still measured in terms of aerage use - not highest use.

At least that is the way I figure it.

OK, even there are spikes in bandwidth measurement, some servers hardly have more than 7 hours/day peak usage averagely. So I don't see any reason why they wanna do 70th percentile billing.

Maybe you mind to elaborate more, or something missing there? :)


i almost forgot...
perhaps to compare the price of bandwidth instead of billing percentile??

Lets say you used 9 megs for 8 hours everyday and only 2 megs at night and your avrage by mrtg was only was 5 megs for the month.

Ok now your provider has to have 9 megs or more ready for you to use at anytime so they have overhead just to make sure you can burst to the full 9 megs everyday.

As you can see you was only charged for the 5 megs but your provider was charged fo the full 9 megs so they have to make this up some how and be fair about it so thus the 95% or the 70% in this case.


Bursting bandwidth will always be billed at the 95% from any large tier 1 provider.

Now on the other hand if you was on a capped line (and nobody likes this) they have flat rate billing for that situation because they dont have the overhead to cover your bursting bandwidth.

Nobody likes the percentile billing but most hosts are charged on it by the tier one providers so they must pass it on to the end customer.

I totally agree here with Paul .. we have been billing on average, but now that we got out own line, they charges us on the 95% . and I have to tell you guys, it's not easy .. :(

Originally posted by CRego3D
I totally agree here with Paul .. we have been billing on average, but now that we got out own line, they charges us on the 95% . and I have to tell you guys, it's not easy .. :(

What's the problem? All it means is that you calculate the prices you charge differently -- instead of basing them on 300GB/Mbps-month, you calculate based on 200GB/Mbps-month.

In a sense, 95th percentile billing is the middle ground between "average" and "unmetered" (aka a capped xMbps line) billing: While with "average" billing every bit costs the same amount, and with "unmetered" billing only the bits during the very peak period cost anything (because the line has to sustain the peak capacity), 95th percentile billing accurately reflects that bandwidth at 4AM is not going to cost anywhere near as much as bandwidth at 8PM to provide (because at 4AM the utilization isn't going to be anywhere near the 95th percentile level).

While I agree that 95th percentile helps you determine how much you need, as in total mbps, it does not truely reflect how much you use. Only an average monthly can tell you that.

Originally posted by WebAuth
While I agree that 95th percentile helps you determine how much you need, as in total mbps, it does not truely reflect how much you use. Only an average monthly can tell you that.

Yep. Anything percentile == paying for more than you use.
<edit> well unless its like 40th percentile or something. :D </edit>

Originally posted by cperciva
What's the problem? All it means is that you calculate the prices you charge differently -- instead of basing them on 300GB/Mbps-month, you calculate based on 200GB/Mbps-month.
I tell you what the problem is .. everybody whats to pay 1.00 a gig for the bandwidth, and they dont whant to oversubscrive, and they whant fries with that too.

Problem is prices are not getting that low, but everybody seems to think they are ;) (damm you cogent)

Originally posted by CRego3D
I tell you what the problem is .. everybody whats to pay 1.00 a gig for the bandwidth, and they dont whant to oversubscrive, and they whant fryes with that too.

Ok, point taken, but that's a problem of people not wanting to pay reasonable rates, it's not a problem with 95th percentile billing.

Blaming 95th percentile billing here is like blaming your calculator because it says you have to pay lots of taxes.

Originally posted by cperciva


Ok, point taken, but that's a problem of people not wanting to pay reasonable rates, it's not a problem with 95th percentile billing.

Blaming 95th percentile billing here is like blaming your calculator because it says you have to pay lots of taxes.

Hoo, but you got me wrong .. I didnt' blame the 95th percentile rule .. not at all, beeing this far in the game .. I like it, I was just saying it's hard when you pay at 95% but the customers don't whant to ;) ..

I am seriously thinkign of adopting the method .. it's much more fair to us too

Originally posted by CRego3D
I am seriously thinkign of adopting the method .. it's much more fair to us too

Be prepared for some funny math.

For small values of x, x Mbps + x Mbps is much less than 2x Mbps, while for large values, x Mbps + x Mbps = 2x Mbps.

95th percentile billing is really best at fairly covering the costs associated with "rush hour" traffic... that is, it accurately reflects the fact that a site which draws 500GB of traffic between 8PM and midnight is far more expensive to provision for than a site which draws 500GB spread equally over the entire day.

However, 95th percentile billing also picks up on the short-term fluctuations in data rates. A single visitor to a site can easily draw 40kbps -- if a site only has a few visitors at any given time, the 95th percentile will not reflect global temporal patterns of bandwidth usage, but will instead reflect the random behaviour of a few individuals.

In terms of purely statistical fairness, I'd say that it only makes sense to utilize 95th percentile billing when the MRTG graphs are reasonably smooth -- that is, when there is sufficient traffic for short-term fluctuations to average out, leaving behind the clear diurnal pattern.

The level at which this occurs will vary, of course, but generally speaking at levels below 1Mbps it doesn't make sense to use 95th percentile measurements, while at levels above 5Mbps it certainly does make sense.

5% shave for 95% is hardly ANYTHING for the peaks.


Most peaks are around 30-40%

When you pay 95% you will pay around 1.5x what you use average.


Nobody peaks for only 5% everybody usually peaks at least 25% a day.

If you think about it, there are peaks from 2:00 EST PM - 9:00 EST PM

thats almost like 7 hours.

7 hours out of 24 hours is what.. 1/3 ?

5% is not going to cover anything :) might as well throw that garbage away and just pay 100%

of course we can't do that. Damn the isps :))

Originally posted by CLEARVERT
5% is not going to cover anything :) might as well throw that garbage away and just pay 100%

CLEARVERT, have you ever seen bandwidth utilization graphs over long time periods? There are two major characteristics of which you seem unaware. First, the graphs are not smooth. Second, some days have more traffic than others; the peak value on one day will be far higher than on another day.

To quote an MRTG graph of my recent acquaintance:
Average Out: 4.081 Mbps
95th percentile Out: 6.169 Mbps
Maximum Out: 10.115 Mbps

Yes, 95th percentile billing seems to be a fair billing method.

Back to the question. Anyone has had 70th percentile billing experience? cperciva what do you think?

70th percentile billing would be ... odd. I honestly can't see why anyone would want to use such a scheme. In some cases it would actually "reward" people for having very bursty traffic.

I haven't yet seen anyone using this; can anyone provide a reference?