Impairment and regenerator aware lightpath setup using distributed reachability graphs

GMPLS-based transparent optical networks suffer from accumulation of physical layer impairments (PLIs) along the optical path and inefficient wavelength utilization due to wavelength continuity constraint. To increase the optical reach, resource utilization, and average call acceptance ratio, network operators resort to translucent optical networks in which a limited number of regenerators are placed at a selected set of nodes. In this scenario development of an optical control plane which is aware of PLIs, location and number of regenerators, is of paramount importance for on-demand lightpath provisioning. In this paper, we propose a novel three phase approach-reachability graph construction, route computation on reachability graph, and signaling-impairment and regenerator aware routing and wavelength assignment (IRA-RWA). We also propose corresponding GMPLS protocol extensions. The simulation results suggest that our proposed approach together with LSP stitching signaling mechanism can be deployed in realworld translucent optical networks.