Routing and wavelength assignment algorithms in survivable WDM networks under physical layer constraints

This paper addresses the problem of survivable lightpath provisioning in wavelength division multiplexed networks taking into consideration the optical signal performance degradation triggered by the physical impairments of transparent optical networks as a routing constraint. This work proposes a resource efficient provisioning scheme that takes into consideration both working and protection traffic. In order to maximize the utilization of spare capacity the backup multiplexing technique is applied in combination with suitable wavelength assignment algorithms differentiating the two types of traffic. In addition, to provide the required quality guarantees an impairment aware routing algorithm that incorporates the main physical layer characteristics of large-scale optical networks into its path computation process is proposed. The performance of the proposed solution is investigated and compared to other conventional RWA algorithms (i.e shortest path, minimum hop and random wavelength assignment) through simulations of a typical mesh long-haul network.