We present an approximate analytical method to compute efficiently the call blocking probabilities in wavelength routing networks with multiple classes of calls. The model is fairly general and allows each source-destination pair to serve calls of different classes, with each call occupying one wavelength per link. Our approach involves two steps. The arrival process of calls on some routes is first modified slightly to obtain an approximate multi-class network model. Next, all classes of calls on a particular route are aggregated to give an equivalent single-class model. Thus, path decomposition algorithms for single-class networks may be extended to the multi-class case. Our work is a first step towards understanding the issues arising in wavelength routing networks that serve multiple classes of customers.
Sridhar Ramesh, George N. Rouskas, Harry G. Perros