Survivable lightpath provisioning in multi-domain optical networks

This paper proposes a survivable lightpath provisioning scheme that allows traffic splitting in multi-domain optical networks to minimize the cumulative cost of a set of paths. The proposed scheme, called two-phase lightpath provisioning´ employs an integer linear programming (ILP) formulation based on hierarchical path computation with full-mesh topology abstraction. There are two phases in the scheme. The first phase solves the ILP problem on an inter-domain topology and then feeds the results as intra-domain requests. The second phase solves the ILP problem in each related domain. Finally, we concatenate all the intra-domain solutions along routing sequences. Three different protection strategies are considered with varying degrees of primary and backup route separation. Furthermore, to support various types of traffic demands, we investigate two cases in terms of the number of requested wavelengths. First, the number of requested wavelengths is less than link wavelength capacity. Second, the number of requested wavelengths is greater than link wavelength capacity. For the latter case, the proposed scheme allows traffic splitting among feasible primary and backup routes. The proposed scheme well supports the implementation of heuristic algorithms for lightpath provisioning since it can provide reference values, including upper and lower bounds, that are useful as benchmarks.