A priority-aware protection technique for quality of service enabled WDM networks

Connection availability is considered as a critical metric,when providing differentiated services in WDM mesh networks. Indeed,one of the major concerns of optical network operators is related to improvingthe availability of services provided to their highest-class clients.Achieving this objective is possible through the use of the different classicalprotection schemes, namely the so-called dedicated and shared protectionschemes. However, the majority of the work concerning protectionschemes has considered the primary connections as equally importantwhen contending for the use of the backup resources.As a main contribution in this paper, we therefore propose an improvementof the existing protection schemes through the introductionof relative priorities among the different primary connections contendingfor the access to the protection path. To evaluate numerically the bene-fits of the service differentiation feature introduced in our proposal, wefirst develop a mathematical model based on which we derive explicit expressionsfor the average connections availabilities that result from boththe classical protection schemes and the proposed priority-aware one.Through this model, we show how the availability of the highest-classclients is improved when deploying the proposed priority-aware protectionscheme. Finally, with the same objective in mind, we develop a simulationstudy, where a given set of connection demands with predefined availabilityrequirements is provisioned, using different protection strategies.Through this study, we show that the priority-aware protection strategysatisfies service-availability requirements in a cost-effective mannercompared with the classical protection schemes.