An isochronous and asynchronous traffic scheduling algorithm for dual-star WDM networks

In this paper, based on the concept of wavelength reusing, a new architecture for interconnecting two wavelength division multiplexing (WDM) star networks is proposed. According to this architecture, the problem of scheduling isochronous as well as asynchronous traffic is investigated. The lower bounds for the problem of minimizing the switching duration and the number of switching modes are derived. A transmission scheduling algorithm for the proposed architecture to efficiently reuse the wavelength is also proposed. For only asynchronous traffic, the analytical result shows that the proposed scheduling algorithm produces solutions equal to the lower bounds. For both isochronous and asynchronous traffic, simulation results show that the average switching duration and the average number of switching modes obtained by the proposed algorithm are quite close to the lower bounds. Simulation results also show that given the same number of users and available wavelengths, the solutions (in terms of the average switching duration and the average number of switching modes) obtained by the proposed scheduling algorithm on the dual-star WDM networks are better than the solutions obtained by the two-phase algorithm on the similar dual-star WDM networks.