Burstable billing

Burstable billing is a method of measuring bandwidth based on peak use. It also allows usage to exceed a specified threshold for brief periods of time without the financial penalty of purchasing a higher committed information rate (CIR, or commitment) from an Internet service provider (ISP).

Most ISPs use a five-minute sampling and 95% usage when calculating usage.

95th percentile

The 95th percentile is a widely used mathematical calculation to evaluate the regular and sustained use of a network connection. The 95th percentile method more closely reflects the needed capacity of the link in question than tracking by other methods such as mean or maximum rate. The bytes that make up the packets themselves do not actually cost money, but the link and the infrastructure on either end of the link cost money to set up and support. This method of billing is commonly used in peering arrangements between corporate networks, it is not often used by ISPs because Internet service providers need committed information rates (CIRs) for planning purposes.