Efficient QoT-Aware Rerouting Algorithm for Differentiated Services in WDM Transparent Networks Provisioned with Set-Up Delay Tolerance

In this paper we investigate further improvement in performances of Wavelength-Division Multiplexing (WDM) transparent networks under two traffic classes referred to as Scheduled Lightpath Demands (SLDs) and Random Lightpath Demands (RLDs). Scheduled traffic corresponds to high priority traffic whereas random traffic corresponds to best effort traffic. Indeed, in such networks, optical signals propagate over long distances without any electrical regeneration. Thus, noise and signal distortions accumulate along the physical path. Since these impairments continue to degrade the signal quality as it progresses toward its destination, the lightpaths' Quality of Transmission (QoT) might become potentially unacceptable. This constraint along with the wavelength continuity constraint imposed by WDM transparent networks might have a severe consequence on the performance of transparent optical networks especially in terms of rejection ratio. In this paper, we propose to apply traffic rerouting concept for network with QoT constraints provisioned with set-up delay tolerance in order to investigate further improvement in network performances under differentiated services. Through simulation results, we confirm that traffic rerouting concept and set-up delay tolerance are an efficient way to improve the performances of WDM transparent networks in terms of rejection ratio and service disruption period incurred by rerouting.