On the efficiency of stream line effect for contention avoidance in optical burst switching networks

The OBS paradigm is a very promising all-optical transmission paradigm; however, OBS still suffers from burst losses because of burst contentions. Consequently, several loss-less approaches were proposed by various authors. In this paper, we investigate further one of them, the CAROBS framework, originally proposed by Coutelen et al. (2010) [15]. CAROBS uses electronic buffering for contention resolution that requires careful routing strategies in order not to entail too many new contentions, and then buffering as a result of these contentions. This led us to look at the stream-line effect in order to devise efficient routing. The streamline effect has not yet been much exploited except for its straightforward implementation. Firstly, we empirically verify the impact of buffering within a stream-line effect framework, and discuss the significance of the results. Secondly, we devise an optimized request provisioning taking advantage of the stream-line effect with a compact integer linear programming (ILP) model, and then with a decomposition ILP model. Thirdly, we proceed with extensive numerical experiments. We run a time domain analysis of the routing obtained from the last ILP model for four referential network topologies. Results show very appealing properties of the CAROBS framework, and in particular, a maximal wavelength efficiency higher than 70%.