Overflow Models for<i>Dimension</i>®; PBX Feature Packages

Abstract

We present numerical results for some traffic overflow systems with queuing. Traffic is offered by two independent streams to two groups of trunks, with a finite number of waiting spaces for each, and some overflow capability from the primary group to the secondary group. We consider three different overflow systems, two of which model feature packages offered in Dimension <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> PBX. For given offered loads and unit mean holding time, we determine the number of trunks and waiting spaces in the two groups so that the blocking probabilities, and the average delays of queued calls do not exceed prescribed values. We also calculate various other quantities, such as the occupancies of the trunk groups and the probability of overflow from the primary group to the secondary group. Finally, we examine the effect on the blocking probabilities and the average delays of varying the loads offered to a given system.