jitter

term

networkingISP & telecom

Variation in delay between packets - the reason a call sounds broken on a link whose average latency looks fine.

Real-time media cares about consistency more than speed, because a receiver has to play audio at a steady rate and can only absorb variation by buffering. A jitter buffer trades latency for smoothness, so the cure and the disease are measured in the same unit. This is why an average is the wrong statistic for anything interactive: the ninety-fifth percentile and the spread say what the user experiences, and the mean hides exactly the packets that ruined the call.

Also known as: delay variation

All glossary entries