Comparison of Opaque and Translucent WDM Networks with Different Regenerator-Placement Strategies under Static and Dynamic Traffic

In this paper we compare the performance of opaque and translucent Optical Transport Networks (OTNs) taking into account different regenerator placement strategies. The translucent approach achieves noticeable results under static traffic in terms of saving of deployed resources. On the other hand in the dynamic scenario a translucent OTN suffers from fewer resources and may display high blocking probability. We describe our planning procedure that is composed of two main steps: the first one selects a subset of network nodes that can host regeneration devices solving the Regenerator Placement Problem (RPP) by the means of three different heuristic allocation algorithms; the second one computes the amount of resources (number of transponders and DWDM systems) accomplishing the Routing and Wavelength Assignment with Regenerator Problem (RWA-RP) to satisfy a given set of static traffic demands. This dimensioning procedure is applied both to a translucent and to an opaque implementation of the same OTN showing the CAPEX benefit of the first approach. Subsequently both translucent and opaque versions of the OTN are simulated under dynamic traffic, displaying the greater robustness of the opaque case to blocking, no matter what regenerator placement algorithm has been adopted. To back up this conclusion we carried out a further analysis on the power consumption.