Randomized and deterministic routing strategies for circuit-switched networks: design and performance

Summary form only given. An investigation of two fundamentally separate classes of routing algorithms, randomized and deterministic, is reported. The main randomized algorithm is the recently introduced dynamic alternate routing algorithm of Gibbens and Kelly. In the contrasting deterministic algorithm, attempts to carry a call are made in a specific precomputed order. The design of these routing sequences is new and depends on (i) analytic approximations based on fixed-point equations for evaluating network performance and (ii) heuristics for the rather complicated problem of network revenue maximization. In all cases an important role is played by the control mechanism of trunk reservations. The testbed is a network of six nodes which is fully connected, except when the effects of various link failures are studied. The network data are quite nonuniform and extracted from a realistic network. The primary tool in this study is discrete-event simulation. Results have been obtained for each of the following goals: (i) to evaluate and compare performance, primarily in terms of revenue generated; (ii) to evaluate performance in the event of link failures; (iii) to develop innovative design tools; (iv) to develop an appreciation of the time constants of the various algorithms; and (v) to propose new algorithms, especially hybrids