Retransmission in slotted optical networks

We consider an all-optical slotted network with contention-based operation where optical switches have neither an electronic buffer nor an optical buffer inside them. Since retransmission could be the cheapest contention resolution scheme in this network, we study and compare both the conventional and prioritized retransmission schemes. In the former technique, traffic retransmission continues until traffic passes the core switch. In the latter technique, dropped traffic is prioritized when retransmitted from edge switches. On the other hand, the core switch processes the prioritized traffic with a higher priority. Thus, the number of retransmissions is significantly limited. We present the analysis of both techniques, and demonstrate via simulation that the prioritized scheme can achieve a better network performance than the conventional retransmission scheme