IGFS: A New MAC Protocol Exploiting Heterogeneous Propagation Delays in the Dynamic Bandwidth Allocation on WDM-EPON

One of the most challenging issues of the Ethernet passive optical networks´ (EPONs) architecture is the bandwidth allocation problem. Various dynamic allocation schemes have been proposed to schedule the subscribers´ demands. However, the performance of all these schemes is significantly degraded when the round-trip times (RTTs) of the optical network units (ONUs) are dissimilar, due to the large number of gaps in the transmission schedule. Unfortunately, in real networks, RTTs are usually dissimilar. In this paper a new medium access control (MAC) protocol for multichannel EPONs, namely the Intelligent Gap Filling Strategy (IGFS) is proposed. The IGFS employs two algorithms: the DissimilarityExploitation algorithm, which exploits the RTTs´ dissimilarities, and the MinimumLatencyScheduling algorithm, which rearranges the ONUs´ service order in order to favor the requests that cause the minimum scheduling latency.