University of Alberta Topology Design for Reconfigurable ATM Networks

ATM is recornmended as the preferred transfer mode to support multimedia services in B-ISDN. The logical VP based network provides an effective way to facili tate the dynarnic resource management in ATM networks. The physical topology of a n ATM network should be designed to provide flexibility to the logical VP reconfiguration in order to adapt to changing traffic conditions and possible network facility failures. In this thesis, we first address the problem of physical topology design for ATM networks with a view to facilitating the logical VP reconfiguration phase. The physical topology design model is formulated as a nonlinear mixed integer programming problem where the objective function to be minimized is defined by considering the balance between the link capacity cost and the link installation cost. Two parameters are introduced in the design model to control the capacity assignments for the primas, and alternate routes respectively. Two graph-based heuristic algorithms are developed to solve the problem by exploiting two important properties of the physical topology design model. In the second part, the performance of generated topologies is s tudied. The two dgorithms are numericdly compared with respect to the computational efficiency and the quality of solution. Extensive computational experiments are conducted t O investigate topological (static) properties of the generated physical networks. The static performance evaluation indicates that the parameter that controls spare Capacity for alternate paths has more effect on the generated topology than the other paameter. The two parameters can be adjusted to achieve better performance with little increase in network cost. Finally, a call-IeveI simulation is carried out to dynamically evaluate the extent to which the generated physical topology provides flexibility to the dynarnic bandwidth allocation at the logical VP level. The dynamic performance evaluation shows that the generated physical topology can achieve the same performance wi t h small extra capacity.