The inconsistency index method for estimating the accuracy of Schweitzer's approximation

Product-form queueing networks have proved to be useful for predicting the performance of computer systems. In practice, these networks are analyzed using approximate methods because exact methods are computationally too expensive. Schweitzer's approximation is one of the most commonly used. However, there is no method for estimating the error in the solution. This paper proposes a new approach for estimating the error in Schweitzer's approximation for fixed-rate product-form networks. It is based on detecting the extent to which the approximation assumptions used hold. Empirical evidence is presented to show that this approach can be used to accurately predict the error in the approximation.