Rearrangeability of Wavelength-Space-Wavelength Switching Fabric Architecture for Elastic Optical Switches

In this paper, we consider the necessary and sufficient rearrangeability conditions for the wavelength-space-wavelength switching fabric, called the WSW2 switching fabric, for elastic optical network nodes. We derive and prove the lower bound of the necessary conditions for such switching fabrics to be rearrangeable. We also show the upper bound of the sufficient conditions for the rearrangeability of the switching fabric with two input and two output switches. For simultaneous connection routing, we propose a routing algorithm that always ends with success in switching fabrics, which fulfill the sufficient conditions. Finally, we extend the proposed algorithm to the switching fabric with r input and r output switches, and we derive the conditions under which this routing algorithm always ends in success. The required number of center-stage switches is significantly lower than that in the strict-sense nonblocking switching fabrics. To our knowledge, the proposed routing algorithm is the first one which ends with success for any connection set, within the provided sufficient conditions.