Online impairments-aware routing within a path computation element

In English A Path Computation Element (PCE) is a computing device in a network capable of calculating paths. Once a PCE receives a path computation request, the PCE is suppose to provide a response within a reasonable short time. However, computing a feasible path is not a straightforward task, since the computational problem must consider several constraints in a short time. In this paper we propose an algorithm for light-paths computation for this purpose that is intended to comply with the PCE standard. Our algorithm considers optical impairments, wavelength conversion and nodes with limited switching capabilities. Optical impairments are estimated using a Q-factor. The routing problem is solved using Multi-Constrained Shortest Path exact algorithm.