Routing and Spectrum Allocation policies for time-varying traffic in flexible optical networks

We consider the problem of serving dynamic traffic in a spectrum flexible optical network, where the spectrum allocated to an end-to-end connection varies dynamically with time so as to follow the required source transmission rate. In the proposed framework, each connection is assigned a route and is allocated a reference frequency over that route, using an appropriate Routing and Spectrum Allocation (RSA) algorithm, but the spectrum it utilizes around the reference frequency is allowed to expand and contract to match the source rate fluctuations. To perform this function, we propose two spectrum expansion/ contraction (SEC) policies and we develop models for calculating the network blocking probability for these policies. We then present an iterative RSA algorithm that takes into account the developed blocking models and identifies the routes and the reference frequency for the connections so as to minimize the average blocking of the network.