Routing in multilayer optical networks

Abstract

A method, system and network for routing a multiplexed signal through an optical network () comprising nodes (A to F) for routing signals along links (to) of the network (), each node (A to F) comprising a lower order matrix () and/or a higher order matrix (). Each matrix () is capable of switching segments of the multiplexed signal between interfaces (N) of the matrix (), the lower order matrix () capable of switching smaller segments comprising fewer channels than the higher order matrix (). The method comprises allocating a cost to using each interface (N) of each matrix (), the allocated cost taking into account a relative value of the lower order matrix () to the higher order matrix () due to the capability of the lower order matrix () to switch smaller segments of the multiplexed signal, generating a cost function associated with possible routes for the signal through the network () from the allocated costs, and determining a route for the signal through the network () by optimizing the cost function. The system and network are arranged to carry out this method.