The Extended Erlang B Calculator is based on the Extended Erlang B traffic model and is used to work out how many lines are required on a trunk group if the traffic and the required grade of service are known. Unlike similar products, you can also carry out these calculations in reverse. For example, you can find out what the probability of blocking would be for a given busy hour traffic figure and trunk group size. If you know two of the variables, you can work out the third.

The Extended Erlang B Calculator provides one important advantage over the Erlang B Calculator: it takes into account the additional load on a trunk group caused by a percentage of blocked calls being immediately retried. This means that the Extended Erlang B Calculator can provide more accurate results when modelling situations in which no overflow facilities are provided.

The Extended Erlang B Calculator supports calculations involving busy hour figures dimensioned in both Erlangs and C.C.S.

See also

The Extended Erlang B Calculator window