Studio Comparativo di Alcuni Metodi di Approssimazione per Reti di Code Chiuse Generali

Queueing network models of contemporary computer systems tend to be too complex to seek exact solutions for the queue length distributions of each device. Several approximation techniques heve been proposed to deal with this problem, but little is known about the accuracy end the reliability of these methods. This paper reports on e study of the results computed by some approximation techniques when used to estimate the performance of a large number of computer's models. The EPF technique appears to be quite reliable, especially when used to evaluate models containing only one general server. This approximation method provides also a good estimate of the homogeneous equivalent model associated to every general queueing network.