Towards the accurate modelling of high-speed communication networks with product-form discrete-time networks of queues

High-speed communication networks and computer systems can be modelled by using discrete-time networks of queues that have a product-form equilibrium queue-length distribution. Although these models can be solved exactly to give a steady-state performance analysis, the models themselves are only approximations to reality in that they do not take into account restrictions imposed by such things as switch capacities, finite buffer sizes, channel capacities or data rates. These problems are addressed in the paper, where methods of refining a closed queueing network model to allow for such restrictions are considered. Conditions are derived for the refined network models to have a product-form equilibrium distribution, and examples of applying the results to obtain product-form networks are given.