Offered traffic (${\alpha }_r={\nu }_r/{\mu }_r$)

For calls arriving at rate ${\nu }_r$ with mean holding time $1/{\mu }_r$, offered traffic is the dimensionless load ${\alpha }_r={\nu }_r/{\mu }_r$, often measured in Erlangs. The Erlang loss formula distinguishes this offered traffic from the mean traffic actually carried.