| With the ever increasing demand for bandwidth intensive applications like video-on-demand, interactive television services, high-definition television (HDTV) and internet telephony, the first mile network, referred to as the last mile network in the earlier stages of its development, has proven to solve the "bottleneck" often experienced between users and the central office. The Ethernet Passive Optical Network (EPON), developed by the IEEE 802.3ah Task Force for Ethernet in the First Mile (EFM), resolves this bottleneck by providing the user with a fiber optic link to the central office that has many advantages, such as nearly infinite bandwidth, low cost, easy installation and immunity to electromagnetic interference, and a saving of the need for powered components in the signal path from the user to the switch. EPONs have proven to deliver the essential services of 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 (QOS). 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.;This research investigates another factor and its effect on 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, deductions regarding load characteristics of some units over others can be made. Decisions can be make about subsequent grant allocations based on this factor and aim to achieve better results in the process. Simulations of EPONs under varying loads incorporating the use of CDP in conjunction with currently used DBA schemes are made and results are analyzed. A major contribution of this research is a new bandwidth allocation algorithm that gives improved performance in terms of packet delay versus offered load. Performance metrics are compared against two common bandwidth allocation algorithms: Interleaved Polling with Adaptive Cycle Time (IPACT) and Cyclic Polling (CP). Additional results also include improvements in packet loss and throughput.;The data that represents traffic for this network has two properties, self-similarity and long range dependency. Plotting the auto-covariance, auto-correlation, and variance for this traffic, for various aggregation levels demonstrates these properties. |
