Loss models in traffic-groomed WDM all-optical networks

The performance evaluation of wavelength division multiplexing (WDM) all-optical networks becomes an exceptionally important research topic, especially when the traffic grooming technique is used. In this paper we develop analytical loss models for calculating route establishment failure probabilities and call blocking probabilities in traffic-groomed WDM networks. We consider both single optical links and mesh all-optical networks with wavelength conversion capabilities. For single links, the proposed models are based on Markov chains and well-established teletraffic models, while, for mesh all-optical networks, they are also based on a reduced load approximation method (RLA). Their recursive nature makes them computationally efficient. In the input process of the models we assume that traffic is originated from service-classes with either infinite or finite traffic-source population. We demonstrate the accuracy of the analytical models by comparing the analytical results with that of the simulation; the results found to be satisfactory.

I. Introduction

The implementation of the WDM technology in optical networks has offered sufficient bandwidth through the simultaneous delivery of data over multiple wavelengths (channels). With each channel operating at high data rates (up to 40 Gb/s), the efficient utilization of these data rates is essential, given that the major percentage of the network users demand only a small fraction of the total wavelength capacity. The traffic grooming technique suggests a resourceful solution to this problem, by multiplexing sub-wavelength demands with dissimilar granularity onto the same wavelength [1]. The completion of traffic grooming reduces the network cost, through the avoidance of the over-dimensioning of the network and the achievement of high utilization of the network resources [2].