Excess bandwidth distribution techniques have recently been proposed to improve the dynamic bandwidth allocation in Ethernet passive optical networks (EPONs). We compare existing offline excess bandwidth distribution with conventional limited interleaved polling with adaptive cycle time (IPACT-limited) in terms of packet delay performance. We identify the factors that result in packet delay reduction with excess bandwidth distribution compared to IPACT-limited and discover that existing offline excess distribution mechanisms become unstable at moderate to high loads in long-range EPONs with large round-trip propagation delays. We propose a novel online excess bandwidth distribution (OEBD) mechanism to provide stable excess bandwidth distribution even at high loads in long-range EPONs. We demonstrate how OEBD can be tuned via parameters to provide grant sizing between limited and gated service.
© 2009 Optical Society of AmericaPDF Article