Towards optimum planning of GMPLS transport networks

The rapid increase in the number of wavelengths per fiber has significantly increased the size of Optical Crossconnects (OXCs) in WDM transport networks. This calls for the use of Multi-Granular OXCs (MG-OXCs) to maintain the scalability of OXCs at a reasonable level. Various MG-OXC architectures and methods for the planning (or dimensioning) of MG-OXC-based networks have been proposed. Motivated by the fact that the MG-OXC constitutes only the optical segment of GMPLS-based transport node, we first propose a new transport node architecture that can handle the whole traffic hierarchy defined in GMPLS. Second, incorporating the proposed architecture with our novel contributions, namely (1) considering grouping and switching of the whole flows defined in GMPLS; (2) allowing bifurcation of multi-granularity traffic demands among different physical routes, requires defining a new transport planning problem, which we call the Routing and Multi-Granular Paths Assignment (RMGPA) problem. The RMGPA problem is formulated as a Mixed Integer Linear Programming (MILP) model with the objective of minimizing the overall network weighted port count.