Performance evaluation model for adaptive hierarchical loss networks

Although the reduced load approximation technique has been extensively applied to flat networks, the feasibility of applying it to hierarchical network model has seldom been described. However, hierarchical routing is essential for large networks, such as the Internet inter/intra-domain routing hierarchy and the PNNI standard. Furthermore, most of research focused on the performance evaluation with fixed routing. Hence, this paper proposes an efficient and accurate analytical model for evaluating the performance of adaptive hierarchical networks with multiple classes of traffic. The evaluation model is based on decomposing a hierarchical route into several analytic hierarchical segments, therefore the blocking of the hierarchical path can be computed from these segments blocking. Numerical results indicate that the proposed adaptive hierarchical reduced load approximation yields quite accurate blocking probabilities as compared to that of simulation results. We also investigate the speed of the convergence rate of the reduced load approximation analysis in both of OD pair level and alternative hierarchical path level.