This paper focuses on high speed networks in a future public network infrastructure. ‘Next Generation Networks’ (NGNs), built on fast IP based packet switching technologies, will provide a unified platform capable of seamlessly supporting a variety of existing and future telecommunications and data services and applications. Requirements on and expected properties of NGNs as the new generation of carrier networks are discussed. An architectural overview reveals the major interfaces and related protocol issues. An implementation approach with emphasis on QoS, network resilience and operational cost issues is presented.