Research On The EPON System And The Dynamic Bandwidth Allocation Algorithm

Getting into 21th century, our communication industy gets into high speed development stage, and the ability of the Internet Backbone Networks improve significantly, but the access networks still don't satisfy person's hope."The last kilometer"is the bottleneck between the Metropolitan Area Network and the Wide Area Network. In fact, the leaders who aim at this problem once proposed various solutions, and always try their best in effort. For example, DSL is adopted by CHINA TELECOM, and HFC is adopted by Broadcast TV Newworks. But viewed from the bandwidth aspect all the solutions just are regarded as the transition. Now fiber is considered to be the most wonderful material to apply in the transmission networks. Once people pay more attention to the APON combining ATM technology and PON technology, but APON become more and more complicated with the upgrading networks, and its cost is so high. So under this background, the EPON (Ethernet Passive Optical Network) technique shows off in our life, because it can provide voice, vidio, and data with its brief structure. And EPON is considered to the best technique of the next generation access networks, because it represente the fusion of the low cost ethernet and the high bandwidth optical network.This text studies some kinds of the key techniques using in the EPON system. In a word, the main work in this thesis is as follows:1) Study the characteristic of the optical access networks especially the EPON system. Compared to some kinds of the access technology, the advantage of EPON is showed as clear as it can be seen, and then elaborate the current status of the research;2) Discusse EPON system structure, MPCP protocol and so on. Then study the structure and the three functions of OAM in the EPON system;3) Because in the EPON system the entire ONUs share the same way in the up channel, we emulate a fixed length DBA to ensure its QoS consulted the method using in the APON system which can provide wonderful standard to deliver the real time information.