Resarch on the Multi Sub-Cycle dynamic bandwidth allocation algorithm

Triple play is the direction of business development for PON network. Current bandwidth allocation algorithms have many problems such as fairness between ONUs, poor light load, lack of differentiated QoS guarantees and so on, when they are used in the multi-service transport network. Based on the analysis of current PON bandwidth allocation algorithms, this paper research an improved dynamic bandwidth allocation algorithm for difficult problems of QoS in Multi-service transmission, which is named Multi Sub-Cycle dynamic bandwidth allocation (MSC-DBA) algorithm. MSC-DBA algorithm divides a complete polling cycle into two sub-cycles, which are used for priority forwarding and conventional forwarding. According to the service priorities in PON network, this algorithm sends different service queues of each ONU to PF and CF sub-cycles for respectively transmission. When the system is in the PF sub-cycle, ONU sends only EF queues, AF and BE queues remain in the cache. Until the EF sub-cycle is exhausted into the CF sub-cycle, the system will send AF and BE queues, according certain rules. It avoids the low priority and high priority services to snatch time slot, increasing high priority service delay in the effective bandwidth. Through pressure simulation for Multi-service transmission, compared with IPACT and T-DBA algorithms. It can be verified that MSC-DBA has certain advantages for efficient bandwidth allocation, which can be applied to the high QoS requirements in multi-service scenarios.