How it works
Your provider records your traffic rate every five minutes for the billing month — about 8,640 samples in a 30-day month. It sorts them from highest to lowest, discards the top 5% (roughly 36 hours of samples), and bills you at the highest remaining value.
Why it is used
It charges for sustained usage while forgiving short spikes, which is fair to both sides.
Inbound vs outbound
Providers usually take the higher of the inbound and outbound 95th percentiles, or bill them separately — check your contract.
Managing cost
- Shift traffic to peering to reduce transit 95th percentile.
- Schedule large transfers outside peak hours.
- Investigate any new sustained peaks.
Planning ports
The same metric is a good basis for capacity planning on your own ports.
