Performance of optical burst switched networks: A two moment analysis

We describe a fairly accurate model for the analysis of optical burst switched (OBS) networks. We use a two-moment approximation to calculate the burst dropping probabilities and hence the throughput of OBS networks. We consider networks with no-deflection of a burst and also networks in which blocked bursts may be deflected from their primary paths. The algorithms that we describe are adapted from the models for circuit multiplexed networks. The adaptation consists of modeling the offered load on the links by accounting for the dropping of blocked bursts on the routes. We obtain a two moment description of the link loads which turn out to be superpositions of several Poisson and non Poisson flows. Further, since the offered load to a link is not Poisson, the dropping probabilities for the different routes on it are not identical and they are evaluated separately. Numerical results show that these features of the model provide a significant improvement in the accuracy of the link and end-to-end burst dropping probabilities. Obtaining accurate link blocking probabilities for each route is expected to help in the better dimensioning of the link capacities and routing.