Some practical considerations on multi-server queues with multiple poisson arrivals

A simple approximate formula is presented and evaluated in this paper for the steady-state average number of customers in the M(x)/G/r queueing system. The derivation of the formula is based on a heuristic argument. Comparisons between approximate results and the ones obtained analytically or by extensive simulation experiments seem to suggest that the degree of approximation achieved is satisfactory for most practical purposes.