Spare Capacity Provisioning for Dynamic Traffic Grooming in Optical Networks

Optical networks with wavelength routing are expected to form the backbone in the next generation wide area networks. The traffic grooming problem in optical networks is an optimization problem of aggregating sub-wavelength traffic demands onto lightpaths such that the required electronic switching capability, hence network cost, can be minimized. In this paper, we propose an over-provisioning scheme, which pre-allocates the spare capacity of lightpaths to dynamic subwavelength traffic demands such that the network can be more agile in responding to traffic increment requests. For the single-link case, the problem is a convex non-linear programming problem. We provide an exact algorithm to find the optimal solution. The problem with general topologies is then studied. We prove the NP-hardness in this case, and propose heuristics. Numerical results show our heuristics perform well.