Two lower bounds on the burst loss probability in optical burst switching networks

Optical burst switching (OBS) is a promising technology which is able to well support bursty traffic and is also technically mature. One critical issue in OBS networks is burst contention. Several methods have been proposed to solve contention such as wavelength converters and fiber delay lines. Among those methods, routing is relatively cost-effective and technically tractable and has been extensively researched. A framework for evaluation the strength of this method is presented in this paper. As routing is a fundamental issue in optical networks and not only confined to OBS, the framework is applicable to a class of connectionless and non-buffer all-optical networks. Through comprehensive analysis of the relation between the total traffic load offered to the network and the traffic load on each link together with some mathematical skills, a lower bound on the burst loss probability is figured out. Extending it by minimizing the lower bound over all reasonable topologies, another lower bound is worked out. With the help of the two lower bounds, comprehensive prospect on the effectiveness of routing and network topologies in reducing the burst loss probability is shown for the first time to the best of our knowledge.