Epon System To Ensure That The Alarm Signal Quality

In recent years,since the rapid development of the network technology, the access network has become the bottle-neck of the whole network. Ethernet Passive Optical Network (EPON) integrates the simplicity of Ethernet, the high bandwidth of the optical transfer, and technology of Passive Optical Network (PON). EPON emerges to be a promising candidate for the next-generation broadband access networks. And EPON represents the latest development trend of the access network,and it is one of the hot studies of current board access network,is thought as the main means to realize future broadband access and FTTH.In this dissertation, some key technologies in EPON system areinvestigated, including study on system structure, MPCP protocol, and bandwidth allocation algorithm, the major achievements are outlined as follows:Firstly, this thesis discussed the development of the access network, some kinds of comparison of PON. Then from definition of EPON system, we illuminate structure of EPON system and operation principle, up and down frame, analyzes the characteristics and key techniques of EPON.And we illuminate implementation of alarm signal over EPON system,including major modules and function.Secondly, for the staticbandwidth allocation and basic DBA algorithm (IPACT algorithm), we analyze some strategy problems in the process of bandwidth allocation, such as priority queuing scheduling and interleaved polling scheme. After analyzing the disadvantages of the current DBA algorithms, alarm signal brought new requirements to the network called low delay and little jitter. The paper mainly focused on the service quality of alarm signal. Build up the simulation model and give out the simulation results.A protection schemes in EPON against link failures between OLT and splitter and splitter and ONUS are provided. The basic protocol in MAC layer with a small modification can support proposed protection schemes in physical layer. Availability and performance of protection scheme are proved. Based on thequantitative analysis to protection structure, we analyze protection structure. Trough simulation in MATLAB, it is proved that the survivability of EPON with protection structure .