The Research And Simulation On QoS Mechanism Of Multi-service IP Bearer Network

QoS (Quality of Service) is the comprehensive index for service satisfaction measurement. The main objective of QoS for multi-service IP bearer network is to provide telecom-class QoS. and provide different levels of QoS according to users'requirements, and to differentiate IP packet of different services and make user admission control. That IP network can not guara specific QoS requirements of a particular business becomes a huge obstacle of the development of integrated service of broadband IP network. Therefore, to study how the multi-service IP bearer network can provide a certain QoS guarantees has become a real and important issue.This paper studies the QoS technology of multi-service IP bearer network, focusing on the admission control mechanism and queue scheduling mechanism. QoS service model is firstly analyzed and compared, through which the Differentiated Service Model(DiffServ) is determined as the basis for this study. Then, admission control techniques as a preventive means of flow control is described and a variety of admission control algorithm principles and their advantages and disadvantages are analyzed. Based on detection technology, Link Parameters Probe Admission Control(LPPAC) algorithm is proposed. LPPAC algorithm collects the detection information of several links and quickly selects one of the links for data transmission. The simulation results on OPNET simulation tool show that LPPAC algorithm can effectively improve the throughput and delay. Finally, the queue scheduling algorithm in congestion control is studied. Based on the analysis of existing queue scheduling algorithms, Adjust Weight Loop Compare (AWLC) algorithm is proposed, and the OPNET simulation results show that:AWLC algorithm can reduce the loss rate and the delay of bursty packets on the occasion of emerging bursty traffic or a large quantity of packet-length changes for specific service.