Queueing Network — Contact Centre
Erlang-C staffing for a 480-call-an-hour contact centre with billing, technical and retention queues, showing why 26 front-line agents at 93% occupancy still leave the average caller queueing over a minute.
Make it your own.
title "Contact centre — weekday 10:00 peak"
target 90%
rate unit /h
arrivals "Front line" 480/h
# Talk time is roughly exponential on the front line; tier 2 is far more
# variable (cv 1.4) because a hardware fault and a password reset are the
# same queue.
station "Front line" { servers: 26; service: 3m; cv: 1.1 }
station "Billing desk" { servers: 11; service: 5m }
station "Technical tier 2" { servers: 18; service: 11m; cv: 1.4 }
station Retention { servers: 5; service: 7m }
route "Front line" -> "Billing desk" 0.22
route "Front line" -> "Technical tier 2" 0.17
route "Front line" -> Retention 0.05
route "Front line" -> exit 0.56
route "Billing desk" -> Retention 0.08
route "Billing desk" -> exit 0.92
route "Technical tier 2" -> "Front line" 0.04 # escalations handed back
route "Technical tier 2" -> exit 0.96
route Retention -> exit 1.0