Burstable Billing

Burstable billing is a method of measuring your bandwidth based on peak utilization. It also allows a user to use more than the agreed bandwidth without the financial penalty of purchasing a higher Committed Information Rate (CIR, "commitment") from an Internet service provider (ISP). DI Dedicated s use a five minute sampling and 95% utilization when calculating the burstable rate.

95th Percentile

The 95th percentile is a widely used mathematical calculation to evaluate the regular and sustained utilisation of a network pipe. It is commonly used among bandwidth providers, e.g. datacenters and upstream providers, for both capacity planning and/or calculating metered use and roughly means ‘for most of the time this was the throughput on the line’.

The 95th percentile is a good number to use for billing as it can allow the customer throughput bursts without any financial penalty. Basically the 95th percentile says that 95% of the time, the usage is below this amount. Conversely, 5% of the time, usage is above that amount.

There are important factors to percentile calculation:

Sampling interval, or how often samples are taken (called also "Data Points").

• A percentile is calculated on some set of data points.
• Every data point represents the average bandwidth used through the sampling interval, calculated as the number of bytes (or KB/MB/GB etc.) transferred divided by the sampling interval length in seconds (effectively representing the average utilisation for single sampling interval).

Burstable rate calculation

Your bandwidth is measured from our switch and recorded in a log file, which is done every 5 minutes. At the end of the month, your usage statistics are sorted, and the top 5% (which equal to approximately 36 hours of a 30-day billing cycle) of data is thrown away, and that next measurement becomes your 'billable utilization' for the month.

Based on this model, the top 36 hours (top 5% of 720 hours) of peak traffic are not taken into account when billed for an entire month. What this means is that you could run at the full rate for up to 65 min a day with no financial penalty.

• With 95th percentile billing you are allowed to briefly "dip into" peak bandwidth when you are require to. For example, if your website has a surge of traffic.

• DI Dedicated will allow you to upgrade your commitment and therefor benefit of other pricing options if they notice these type of peak patterns.