Since telecommunication operators have commercialized VoIP services recently, it is important to provide quality of the call across networks. It is demanded that the same quality as PSTN provides should be supported in VoIP networks too. Several QoS solutions have been developed and proposed for VoIP service in many organizations for this purpose. In this paper, we explain several QoS Solutions for IP networks, and present the QoS architecture for Next Generation VoIP Networks, which is proposed by Multi-service Switching Forum.(omitted)