On Regenerator Placement in Loss-less Optical Burst Switching Networks

Optical burst switching suffers from burst contention, which can occur even under low load. This issue was investigated by Coutelen et al., 2009 and led to the CAROBS framework. Therein, the authors considered burst concatenation, and with the recourse to wavelength conversion throughout signal regeneration, can resolve all burst contentions, offering then a loss-free OBS framework. However, CAROBS does not take into account physical layer impairments, which can lead to OSNR degradation and ultimately optical burst losses. In this paper, we investigate how many additional optical regenerators need to be introduced in order to overcome those physical impairments in translucent OBS networks. We propose two different heuristics in order to optimize the regenerator locations. Numerical results are presented in order to both investigate the number of regenerators that need to be installed in order to minimize burst loss, ultimately to reach no burst loss, and the signal degradation due to physical layer impairments.