Research On Network Congestion Control Algorithm In Hiberarchy Qos

With an expansion of the customer quantity and an increasement of the Service,many new services over the IP network have become to implement,such as VoIP,IPTV etc.Meantime,the service provider want to set up the next generation networks based on the existing access network that will require the network equipment can not only distinguish the network traffic more meticulously,but also are able to provide the integrated management and hierarchical scheduling for the transmission objects such as multi-users,multi-operations,multi-flows.The general QoS policy can not meet the demand,thus a new Hiberarchy QoS scheduling policy comes into being.This paper is set in the realization of Hiberarchy QoS in Routing Switch.In-depth analysis is made in the differentiated service model of QoS and the key technologies,such as traffic policing,traffic shaping,congest management,congest avoiding,data packets classifying.The basic principles of the Hiberarchy QoS scheduling model are expounded and the realization of it in network devices is done.The queue scheduling and the queue management on the network congestion control algorithms in Hiberarchy QoS are delved into in this paper.The four user-level in the scheduling algorithm of the Hiberarchy QoS scheduling model,such as port layer,user group layer,user layer and service layer are analyzed.It achieved a integrated management and hierarchical scheduling for the transmission objects such as multi-users,multi-operations,multi-flows.Then,the performance of the Hiberarchy scheduling is verified.In view of the advantages and disadvantages of the RED algorithm which is widely used in current network equipments,in-depth analysis of the reasons for its disadvantages is made.Research is done on the improved fairness-based active queue management algorithm.Without increasing the complexity,the algorithm can adapt the packet loss rate according to the changes of the network load,and the fairness of network bandwidth is taken into account.The algorithm can solve the problem of non-adaptive flows seizing the network bandwidth in case of congestion,having good scalability.Finally,this paper realized the improved algorithm on Network Simulator-NS2.Compared to RED algorithm,the experimental simulation results show that the new improved algorithm performs better.