The DBA Algorithm Research In GPON Network

Explosive growth of the IP data traffic demands more form optic transmission network, such as increasing need of bandwidth, Dynamic Bandwith Assignment, the introduction of Gigabit Passive Optical Networks (GPON) meets these demands. GPON has wide bandwidth,high efficiency,large coverage,flexible user interface advantage. It is regarded as the ideal technology of realizing access service broadbandwidth,totalization by most of the operating agencies.In this dissertation, the PON network technology generation and evolution, FTTx market and trend, GPON technology standard development process, the difference between GPON and APON,BPON,EPON, system architecture of GPON network, working principle and key technique etc. are introduced. It analyzes the significance and research direction of GPON DBA technology.Then the GPON protocol architecture,function is deeply researched, DBA key concept and realizing principle is introduced. This dissertation also give a summary on all the exist DBA algorithm, their own characters and comparison. Then it submit a new DBA algorithm, analyze its package delay time,network throughput,system bandwidth usage rate and bandwidth distribution efficiency advantage. This algorithm is based on T-CONT 5, converge four type of services into one T-CONT 5, but needs to add the different type of service's queue length in the T-CONT DBRu field, when the system total assignable bandwidth is bigger than the request, OLT assign the bandwidth based on the request; when the system total assignable bandwidth is smaller than the request, OLT assign the bandwidth based on the service priority and commands.In the last chapter of this dissertation, it uses OPNET network simulation tool to modeling the GPON OLT ONT ODN nodes. Through different service combination, simulate the performance of new algorithm in different kind of circumstance. The simulation results says that this algorithm can meets different customers different service's QoS to the best within certain limits. It has the advantages in the respect of package delay time,network throughput,system bandwidth usage rate and bandwidth distribution efficiency etc.