Dynamic Bandwidth Allocation Design And Simulation For Multiple Business In Epon System

21century as the era of network, people’s dependence on the network is more and more frequent, and people’s requirement for network bandwidth is also more and more high. At present, the core network all have optical fiber and high transmission rate, but access network called "last mile" problem, is still bottlenecks of the entire network restricted. Although there are ADSL, Wimax and other access technology, but there is no doubt that optical transmission medium for the FTTx is the leader.EPON is the mainstream FTTx technology, constituted a point to more structure by OLT, PoS and ONU. OLT transfers data to ONU by broadcasting, multiple ONU transmit data to OLT by TDMA way and PoS mainly transmits data according to the destination address like switch. The key problem of EPON is at what time the ONU uploads data can make the bandwidth utilization rate more highly and the delay more shortly. This problem collectively refers to as BA problem. The existing IP ACT algorithm and CPFCT algorithm are two classical DBA algorithm. But they also have defects:In light load, IPACT’s bandwidth utilization rate is low and its delay jitter bigly; In height load, utilization rate of CPFCT algorithm is very low, but its stable delay is very suitable for business wiht high sensitive delay. In order to guarantee the time delay and improve the utilization rate of bandwidth as far as possible, the main job of this paper content as follows:(1) analysis performance of IP ACT algorithm and CPFCT algorithm, and then put forward the improved algorithm.(2) build EPON system by OPNET simulation platform, introduce IPACT algorithm, CPFCT algorithm and improved algorithms into EPON system, and collect the simulation data.(3) take Analysis Configuration as Analysis tools to Analysis simulation data, and then compare and analyze the time delay and bandwidth utilization performance.