Future telecommunication networks are likely designed along the Next Generation Network (NGN) framework of the ITU-T. End-to-end Quality-of-Service support---independent from underlying transport-related technologies---is one of the fundamental requirements of NGNs. This paper presents an overarching QoS control architecture that is based on the IETF's Next Steps in Signaling framework. It provides a detailed discussion of how the NSIS approach fits into the NGN architectures, its coupling to the IP Multimedia Subsystem, and possible migration paths from centralized to more distributed approaches. Advantages of using NSIS as part of an NGN-based QoS architecture are pointed out and implementation results for parts of a proposed NGN architecture are presented.