Dynamic Bandwidth Allocation Algorithm. Epon Uplink

As an important solution for access network, EPON has mature technology and wide application. It provides Multi-Service basing on Ethernet. It combines the advantages of PON and Ethernet. With its feature of high bandwidth, low cost, and being used and updated easily, EPON is one of the best solutions to broadband access network. In EPON, the typical network topology is point to multi-point. A downstream packet is broadcasted by OLT to all ONUs. For upstream transmission, all ONUs share a single fiber, which is the key technology of EPON. The alternative solutions to upstream include WDMA, TDMA, CDMA, and CSMA/CD, among which we adopt TDMA at present.In this paper, existing dynamic bandwidth allocation (DBA) scheme is introduced and a novel DBA algorithm over QOS is presented, which has fixed cycle, based on the self-similarity character of network traffic. The novel OLT-based polling scheme has a fixed polling cycle (2ms). ONU's buffer receives different data packets from user, and these packets are classified and then placed into their corresponding appropriate priority queue. It is shown from the simulation results that the algorithm improves bandwidth utilization of uplink and ensures the QOS of different services and shows satisfied delay performance. In addition, DBA scheme over SLA is discussed, based on the implementing of DBA in actual system of EPON. The scheme supports multiple services and provides different bandwidth service guarantees for different service such as fixed, guaranteed and extended bandwidth service. In this paper, the software designing of EPON is presented.This thesis is about the designing and implementing the DBA scheme. The main contents are as follows:1) In the first chapter, the concept of access network is introduced and the technology of EPON is summerized.