The Analysis And Guarantee Of The NGN QoS

With the developing of IP technology and computer communication technology in 1990's, people realized that the "three networks"(telecom network, computer network, cable television network) must evolve into "one network" that based on IP package switching. That network is called NGN (next generation network) .Every type of service based on IP package can realize intercommunication, so people firstly have a communication protocol that all three networks can accepted. Although with some disputes ,the NGN become a common standard ,that is the developing direction . Telecom Service providers in some countries have constructed their NGN networks. A telecommunication revolution have coming up.With the scale of NGN becoming more and more huge, the QoS (Quality of Service) of NGN become more and more important. In NGN, almost every service is based on IP network. But IP network only provide "Best Effort" service, cannot provide exactly real time service, especially voice and video service. Comparing with traditional telephone service on PSTN , people hardly accepted the quality of service over IP. Thus the research on NGN QoS have theoretically and practical significance.This paper firstly introduce the network structure of NGN and some OSI's research on NGN. Because the NGN is based on IP switching, the paper analyze some kinds of traditional IP QoS techs: IntServ,DiffServ,MPLS,CAC and so on. NGN have four level's structure, paper analyze QoS parameter and norms in Service Level, Control Level and IP Level, especially emphasized on some video and vice service. The paper introduce some QoS mapping, especially from IP QoS to ATM QoS and MPLS QoS.Based on the former analysis and practical experience, the paper research QoS solution, provide some practical and systemic proposals based on MPLS,VPN,TE,especially provide a feasible QoS solution for NGN Voice Service.Finally, paper introduce OPNET, that is the common simulation software in telecom and computer network research. And how to use OPNET to realize level modeling,servie modeling,traffic modeling on NGN, and provide a example about RSVP QoS protocol modeling analysis.