New features for the Queueing Network Analyzer (QNA): Deterministic routes plus probabilistic transitions and customer creation.

The Queueing Network Analyzer (QNA) is a software package developed at AT&T Bell Laboratories to calculate approximate performance measures for systems that can be modeled as queueing networks. This memorandum has been used as the basis for developing QNA 3.0, a new version of QNA written by Randall Sandt of Department 52511. It is also being used as the basis for developing an enhanced version, QNA 3.1. The new features described here were developed in response to needs identified in the modeling of production systems. The first version QNA 1.0, can represent probabilistic transitions, customer creation or combination, and multiple customer classes each with their own deterministic route through the network, but these features are not available simultaneously. In this memorandum we describe a procedure to analyze queueing networks with all these features together. The main input format still exploits deterministic routes, but also includes additional probabilistic transitions from these routes.