Comparison of contention resolution strategies in OBS network scenarios

Optical burst switching (OBS) has attracted interest as a transport network architecture for the future optical Internet. As OBS relies on statistical multiplexing efficient contention resolution is a key issue in order to achieve a low burst loss probability. Basically, contentions can be resolved by wavelength conversion, deflection routing and delaying the burst in a fiber delay line or a combination of these schemes. This paper compares the basic and combined contention resolution strategies in two reference core network scenarios with respect to burst loss probability and end-to-end transfer delay. We show that the effectiveness of those contention resolution schemes highly depends on the load offered to the network and the dimensioning of specific nodes and links. For high load, contention resolution schemes applying deflection routing have an end-to-end transfer time increase in the order of 10-60% depending on the scheme.