Investigating cycle demand proportionality in Ethernet passive optical networks

Advances in high speed network communications have raised the bar of delivering demanding multimedia and data services through Ethernet passive optical networks (EPONs). At their relatively low cost, EPONs have become an attractive solution to providing essential services like voice, video, and data communications reliably, while at the same time providing expected guarantees of the delivery of those services in terms of defined quality of service measures. A continuous theme throughout EPON research has been the study of efficient dynamic bandwidth allocation (DBA) as a key factor in achieving fairness in distributing bandwidth amongst remote network units. In our research, we investigate another factor and its effect of network performance and service delivery: cycle demand proportionality (CDP). By observing the patterns of demand in the network on an individual network unit basis cycle after cycle, we can deduce load characteristics of some units over others. We can then make decisions about subsequent grant allocations based on this factor and aim to achieve better results in the process. We simulate EPONs under varying loads and incorporate the use of CDP in conjunction with currently used DBA schemes. In this paper we present results of achieving improvements in delay performance under light-load circumstances for the cyclic polling DBA scheme