Routing and regenerator planning in a carrier's core reconfigurable optical network

The introduction of colorless-directionless reconfigurable-optical-add-drop multiplexers (ROADMs) brings new capabilities to the physical network, including bandwidth pre-positioning, bandwidth-on-demand, optical layer mesh restoration, and wavelength defragmentation. In order to utilize these new capabilities, carriers need to pre-deploy transponders at endpoints as well as regenerators at intermediate locations when needed. Optimizing routing and regenerator planning in a carrier's core ROADM network provides significant savings. In this paper, we describe our algorithms to minimize the total number of regenerator sites and the corresponding number of regenerators needed at each chosen site. We consider both bandwidth-on-demand wavelength services and multilayer restoration needs to provide the upper layer with more efficient restoration. Portions of this work were presented at the Optical Fiber Communications Conference and Exhibition (OFC), March 2017.