Design of private backbone networks-I: Time varying traffic

Technological advances, special communication needs and potential cost advantages are prompting an increasing number of businesses to configure private communication networks, bypassing the public networks to varying degrees. In view of the high prices of leasing capacity, this paper develops a model for determining transmission line capacity in private backbone networks, such that multi busy-hour point-to-point circuit requirements can be met at low cost. Recent technology has developed backbone nodal elements, such as Networking Multiplexers/Digital Cross Connect Systems, which can be easily reconfigured to reroute traffic so as to take advantage of noncoincidence of demand among communicating node pairs across different busy-hours. A multi-period cost model is formulated. A 3-phase heuristic, based on Benders decomposition, is developed to determine the line capacities jointly with circuit routing to satisfy the time varying circuit requirements at low cost. Computational results on practical sized backbone private networks are shown and solution quality is established by comparison with a lower bound obtained from an LP relaxation of the model.