Two tandem queues with general renewal input - II: Asymptotic expansions for the diffusion model

In Part I we formulated and solved a diffusion model for two tandem queues with exponential servers and general renewal arrivals. We thus obtained the heavy traffic diffusion approximation to the steady state joint queue length distribution for this network. Here we study asymptotic and numerical properties of the diffusion approximation. In particular, analytical expressions are obtained for the tail probabilities. Both the joint distribution of the two queues and the marginal distribution of the second queue are considered. We also give numerical illustrations of how this marginal is affected by changes in the arrival and service processes.