Reduced load approximation analysis for fixed hierarchical routing

The reduced load approximation technique has been investigated for flat networks successfully. Nevertheless, less attention has been focused on hierarchical network model. However, hierarchical routing is essential for large networks. For example, the ATM PNNI standard and the Internet inter/intra-domain routing hierarchy. Hence, the goal of this paper is to propose an efficient and accurate analytical model for evaluating the performance of hierarchical networks with multiple classes of traffic. We first study the reduced-load approximation model for multirate loss networks, and then propose a new model for networks with hierarchical routing. Our numerical results show that the proposed hierarchical reduced-load approximation yield quite accurate blocking probabilities as compared to that of simulation results