The condition in which a communications system, link, or switch is processing traffic at its absolute maximum capacity. In telephony, this is typically measured as one erlang per circuit, meaning the line is continuously occupied. When a system hits saturation, any additional incoming calls or data packets are either queued, delayed, or dropped entirely.
The trunk group hit saturation during the morning rush, so callers started getting fast busy signals.
Related terms
erlang
An erlang is a unit of telecommunications traffic measurement representing one hour of continuous voice or data use.
Blocked
A state where a call or connection attempt is rejected by the network switch or firewall.
Fast busy signal
A rapid pulsing tone indicating that the telephone network cannot route the call.
Contention
A state where multiple devices or users attempt to use the same network resource simultaneously.