Combined probabilistic deflection and retransmission scheme for loss minimization in OBS networks

Optical burst switching (OBS) is an appropriate optical switching technology for optical internet considering the bandwidth requirements and technological constraints. However, burst loss remains to be the critical issue in the bufferless OBS network. Many contention resolution schemes were proposed in the literature to address this issue. Deflection routing is regarded as an attractive method for contention resolution in OBS networks. To further reduce the loss, hybrid schemes combining deflection and retransmission were proposed. In this paper, a new hybrid scheme combining the limited retransmission and deflection namely combined probabilistic deflection and retransmission (CPDR) is proposed to achieve loss minimization, overcoming the adverse effects of pure deflection and pure retransmission. The proposed protocol is found to provide 25 percent to 60 percent reduction in burst loss with respect to other similar protocols at higher load conditions. An analytical model is also developed to estimate the burst loss probability of the proposed protocol and the predicted results are found to be in good agreement with simulation based results.