Téléphonie
Erlang
An Erlang is the standard unit of telephone traffic intensity. One Erlang represents one hour of call traffic in one hour — equivalently, a single circuit occupied continuously.
Offered load in Erlangs is call volume multiplied by average handle time, divided by the length of the interval. 100 calls of 180 seconds each arriving in a 30-minute interval is (100 × 180) / 1,800 = 10 Erlangs.
The unit is named after Agner Krarup Erlang, the Danish mathematician who founded traffic engineering while working for the Copenhagen Telephone Company in the early 1900s. His work on telephone exchanges still underpins contact-centre workforce planning a century later.
Offered load sets the floor for staffing: you always need more agents than Erlangs. A queue staffed at or below its offered load has no stable service level at all — the backlog grows without bound.
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Questions fréquentes
How do you calculate Erlangs?
Multiply the number of calls in an interval by the average handle time, then divide by the interval length in the same units. 100 calls at 180 seconds each in a 30-minute interval is 10 Erlangs.
Termes associés
Voyez Erlang dans un véritable appel.
Réservez une démo de 30 minutes et regardez Finn gérer les appels entrants et sortants de bout en bout — aucune pile technique à assembler.