TNPFA 4.1.1 Installation and User Guide - e IBM Tivoli Composite ...

Appendix B. 95 th percentile billing
The 95 th
percentile is a widely used mathematical calculation to evaluate the regular and sustained utilization of a
network connection. The 95 th percentile method more closely reflects the needed capacity of the link in question than
tracking by other methods such as mean or maximum rate. Rather than charge for total traffic, customers get charged a
per-megabit rate (Mbit/s). This rate is calculated by taking 5-minute transfer rate readings throughout the month, then
disregarding the top 5% of readings (in an attempt to remove all of the spikes) and charging for the next highest rate on
the list.
Figure B-1 demonstrates the 95 th
percentile rate for sent and received traffic for a particular month.
Figure B-1 95th Percentile Rate
Figure 9-1 shows how the customer’s interface ports on their routers and switches are polled or sampled at regular
intervals throughout the billing cycle. In this example, 8,640 samples are accumulated in a 30 day calendar month. Each
sample contains the number of bytes transmitted to the customer and the number of bytes received from the customer
since the sample took place.
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