Measurement-based alternative routing strategies in optical burst-switched networks

Optical burst switching (OBS) is a very promising technology for the next generation of optical Internet. In OBS networks, contention caused by multiple bursts competing simultaneously for a given wavelength on a fiber link, significantly increases the burst dropping probability and hence deteriorates the overall network performance. That is the reason why finding solutions in order to minimize burst dropping due to resource contention is one of the critical design issue in OBS. This paper proposes and analyzes three new deflection routing strategies that resolve contention with significantly better performance compared to the previous ones that have been previously proposed. One of the drawbacks of the deflection routing mechanisms presented in the literature is their lack of flexibility for computing the alternative paths based on some clear design constraints. The proposed deflection strategies are based on different alternative path computing methods with a burst dropping anticipated feature: (i) Least loaded node (LLN), (ii) LLN/U-turn and (iii) LLN/U-turn with load balancing. Simulation was conducted on the Pan-European COST 266 optical network to analyze the proposed strategies.