An optimization approach for survivable lightpath provisioning in multi-domain optical networks

This paper proposes an optimization approach for survivable lightpath provisioning that allows traffic splitting in multi-domain optical networks to minimize the cumulative cost of a set of paths. The proposed approach, called two-phase hierarchical optimization, employs an integer linear programming (ILP) formulation based on hierarchical path computation with full-mesh topology abstraction. There are two phases in the approach. 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, namely same domain sequence (SDS), link disjoint (LD), and domain disjoint (DD) are considered with varying degrees of primary and backup route separation. Furthermore, we evaluate our approach from two points: the effect of traffic demands and the effect of link capacity. The results show that the LD strategy gives notably better performance than the other strategies in both points.