Arbitrary open queueing networks with server vacation periods and blocking

A cost-effective decomposition algorithm is proposed for the approximate analysis of arbitrary first-come-first-served (FCFS) open queueing network models (QNMs) with Generalised Exponential (GE) external interarrival time and service time distributions, multiple vacation periods, exhaustive service scheme and repetitive service blocking of random destination (RS-RD). The algorithm is based on a new product-form approximation suggested by the information theoretic principle of Minimum Relative Entropy (MRE), subject to marginal mean value constraints and a prior joint distribution estimate of the corresponding open QNM with infinite capacity. The censored GE/GE/1/N queue with exponential server vacations is solved via relative entropy minimisation and in conjunction with associated effective flow streams (departure, splitting, merging), plays the role of an efficient building block in the solution process. An exhaustive validation study against simulation is included to illustrate the credibility of the MRE results.