Bandwidth

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If you're a high bandwidth customer then our usual "gigabytes per month" data transfer commitment may not make sense for you. It's not the way that bandwidth is usually purchased in large quantities and it's not how BitFolk deals with its suppliers either.

At high levels of bandwidth use, attempting to sell you a limit of a simple number of gigabytes transferred per month risks giving you a bad deal or exposing BitFolk to overage charges that can't be passed on to you.

95th percentile billing

The most common industry standard billing method for burstable bandwidth charges is referred to as 95th percentile billing. If you're in the market for large amounts of bandwidth then you probably know how 95th percentile works and just want to know our pricing. Here goes.

Pricing

Item Monthly cost Quarterly cost Yearly cost
Base VPS including 4Mbit/s bandwidth 95th percentile £8.99 £24.70 £89.90
Additional 1Mbit/s bandwidth 95th percentile £1.50 £3.80 £15.00
Overage outside of commitment, per 1Mbit/s or part thereof, 95th percentile £3.00

All prices exclude VAT.

For low levels of bandwidth usage you can choose whichever billing method you like. The majority of customers do very little data transfer and will probably find it much simpler to go with the included transfer quota of the usual method, therefore that is the default and we will not ask you about it unless you start doing much more data transfer.

How it works

If you haven't heard of 95th percentile billing before, here follows a full explanation which should enable you to work out if it could make sense for you to switch to it.

We also specify our exact method since there are a few little variations in how providers do such calculations.

Concept

95th percentile billing is designed to give a fair treatment of bursting bandwidth requirements. It recognises the fact that there will be some spikes of usage but that most of the time the requirements will be much lower, and matches costs to those requirements.

Our procedure

The procedure is as follows:

  1. Rates of data transfer in and out in bits/second are measured every 5 minutes.
  2. At the end of the 30-day measurement period the 5 minute readings are ordered low to high, one set for the in readings and one set for the out readings.
  3. The top 5% of each (there's 8,640 5-minute readings in 30 days, so that is the top 432 readings) are discarded.
  4. The highest remaining reading in each set is your 95th percentile measurement for in or out.
  5. We bill you based on the higher figure of those two.

The above method will discard the top 5% of traffic spikes. That is, 95% of all individual readings will be at or below the level you are billed at. As a consequence:

  • If you have a mostly constant bandwidth requirement then you will generally do quite well out of 95th percentile billing.
  • If you have very spiky requirements then you will generally do less well.
  • An anomalous bandwidth use event lasting less than 36 hours (432 × 5 minutes) should not feature in your billing at all.

Frequently asked questions

Is there any point in me switching to 95th percentile billing?

If you currently always do less than the included limit per month (at the moment that is 2000GB) then no, there is no point.

If you are paying to do a lot more than 2000GB/month then it may make sense, especially if you are already paying yearly.

The only way to be sure is to measure your actual traffic.

How do I know how much I can transfer for a given 95th percentile commitment?

An example of a Cacti 95th percentile bandwidth graph.

It totally depends on how "spiky" your traffic is.

Taking the default 4 megabits/sec commitment: If your traffic is very constant and remains near 4 megabits/sec at all times (less than 5% of readings above 4Mbit/s) then it is a simple calculation:

4000 × 1,000 bits × 60 seconds × 60 minutes × 24 hours × 30 days = 10,368,000,000,000 bits per month
10,368,000,000,000 bits ÷ 8 = 1,296,000,000,000 bytes per month
1,296,000,000,000 bytes ÷ 1,000 = 1,296,000,000 kilobytes per month
1,296,000,000 kilobytes ÷ 1,000 = 1,296,000 megabytes per month
1,296,000 megabytes ÷ 1,000 = 1,296 gigabytes per month

Very few people's traffic remains constant, however, and estimating visually can be quite difficult.

If you'd like to get a figure from past data you can ask BitFolk support to do a calculation for any time period in the last 6 months. If you'd like to get an estimate for the future then you can look at your Cacti graphs as these include 95th percentile measurements. It'll end up looking something like the image on the right. Do bear in mind that Cacti shows 95th percentile measurements for the range you ask for, so you should only look at 30 day time spans.

What happened to the doubling of inbound quota?

At these high traffic levels BitFolk can't offer that unfortunately. The higher of your in or out readings are taken as the 95th percentile measurement.

How does overage work?

Your commit level is deducted from your actual measurement and if there's anything left it's divided into blocks of 1Mbit/s or part thereof, the cost of which is detailed above.

How do the data transfer warnings work under 95th percentile?

At the moment unfortunately they do not work at all. Very few customers are interested in 95th percentile billing and the warnings system for data transfer hasn't yet been adapted to cope with this. You will need to monitor your own bandwidth usage if you switch to 95th percentile billing.