Approximate Performance and Sensitivity Analysis of Closed Queueing Networks

A new heuristic algorithm called QNA (Queueing Network Analyzer), has been proposed by the authors for the evaluation of the average performance measures in a queueing network, This algorithm iteratively computes mean queue lengths, throughputs and machine utilizations by means of heuristically derived formulas. The same approach is extended to the computation of the partial derivatives of the same quantities with respect to the parameters of the routing policies. This can be accomplished by considering aside to the basic algorithm an additional set of equations which give, at convergence, the desired sensitivity coefficients.