Double-phase polling algorithm based on partitioned ONU-subgroup for high utilization of fiber channel with EPON

Ethernet passive optical network (EPON) is the next generation technology to avoid the bottleneck problem in high-capacity access networks. In order to allocate time-slots of fiber channel efficiently, it performs polling based on multi-point control protocol (MPCP). We study previous polling algorithms and propose a novel one that increases channel utilization on capacity. This approach divides a polling cycle, consisting of a data up streaming period and a computation period for dynamic bandwidth allocation, into two sub-polling cycles. It allows the two sub-polling cycles to poll in parallel, which reduces a polling cycle time. It not only decreases channel idle time but also accommodates bandwidth requests by optical network units (ONUs) effectively. It is found from comprehensive computer simulation results that, compared to previous work, the proposed algorithm postpones the saturation points of packet delay and ONU queue size and has outstanding network throughput as well. In comparison with the previous research, it has up to about 81% lower average packet delay, up to about 53% smaller average ONU queue size, and a maximum of 15% performance in terms of network throughput.