Research And Realization Of Guaranteeing QoS Of Multi-service In GPON System

As one of the main optical access technology, GPON is thougth as the best Broadband Access Network, based on supporting many kinds of rate, guaranteeing QoS of all services, survivability, High efficiency, and fully considering the suggestions of Service ProvidersThe series of GPON standard are proposed by telecom operators, so it cares more about operation interests, and has obvious advantages in supporting multi-services and guaranteeing QoS. The core of guaranteeing QoS of services in GPON system is Danamic Broadband Allocation (DBA). OLT knows the congestion of network through checking the DBA report from ONU and/or detecting the input service flows, and then allocate bandwidth on the basis of DBA. DBA provides many kinds of QoS for GPON system through four kinds of bandwidth and five kinds of T-CONT, which meets the requirements of Latency, Jitter and Frame Loss for services. However, DBA of OLT only considers the QoS of PON, especially MDU. When congestion appears, normal services will be affected, so ONU needs to manage the bandwidth allocated by OLT. Through deep analyzes of network and service, the optimization scheme of QoS is proposed based on bandwidth utilization, service type, service priority , bandwidth allocation, and so on. So, the scheme can be used for improving the bandwidth utilization and the QoS of GPON system, and then users can use bandwidth effectively and enjoy services with high quality.In this paper, the significance of research is depicted based on the analyses of the domestic and international development on GPON. Then the requirement and challenges of GPON multi-services QoS are discussed through analyzing the QoS parameters and requirements of data service, voice service and image service. And the dynamic bandwidth allocation method is proposed based on UNI of ONU in GPON system, which includes the design of bandwidth allocation algorithm on UNI, the feasibility analysis of the algorithm, and the design of device drivers. Futhermore, some key technologies used in the algorithm and realizes the algorithm are analyzed and realized through programming. After that, the bandwidth allocation algorithm is tested, and its availability is checked. And the result shows that the algorithm can improve the QoS of GPON system and then achieve desired goal. Finally, the dissertation is summarized and some expectations for the next research are put forward.