Quality of Protection on WDM networks: A Recovery Probability based approach

Abstract

WDM networks survivability needs a flexible quality of protection (QoP) due to the variety of existing connection demands, lack of fair resource distributions under traditional QoP and optimal resources assignment. Thus, this paper proposes a new paradigm of QoP based on generic levels of protection where the set of protection levels can be defined as the network administrator needs, i.e., a flexible QoP approach whose particular case is the traditional or non-flexible QoP approach. Essentially, the proposed generic level is based on the recovery probability concept which measures the grade of conflict among primary lightpaths that share backup lighpaths for link failure recovery. In order to study how this strategy impacts on the network cost, a Genetic Algorithm is proposed. It calculates the primary and backup lightpaths, considering a multi-objective optimization on the basis of lexicographical sorting approach. The Genetic Algorithm minimizes the number of blocked requests, the number of services without protection, the total differences between the requested QoP and the assigned QoP, and the network cost; all of which by considering the optical fibers used and subject to the wavelength usage as constraint. The experimental results indicate that the proposed approach –flexible QoP– is a promising strategy where the network cost, the number of requests and QoP levels are contradictory objective functions in environments with homogeneous and heterogeneous QoP requirements.