Performance Evaluation of Hierarchical Routing in ASON Networks

The design and dimensioning of ASON networks are still an open question. Very little is still known on how these phenomena impact the network performance or scalability. In this paper, we have designed a four-layer hierarchical topology structure and developed the simulator. A hierarchical routing algorithm is also proposed. Utilizing the simulator, we analyze the trade-off between performance and scalability in hierarchical ASON networks. Especially, the blocking probability is both affected by the different aggregation schemes and by the different layers. Simulation results show that topology of two- and three-layer has much lower blocking probability than that of four-layer in term of both nodal load and number of nodes. Two- and three-layer are better suited for ASON hierarchical networks. Additionally, minimum spanning tree (MST) is a good aggregation scheme and performs slightly better than star in blocking probability.