In recent years, there has been widespread global interest in the Next-Generation Network (NGN) model as a framework for the evolution of packet-based networks. Extensive standardization efforts lead by the ITU-T and regional standards development organizations such as ETSI and ATIS have generated a broad industry consensus on the basic NGN architecture model and services, as well as other related domains of interest. Much of this activity has been documented by the ITU-T NGN Focus Group in its Technical Reports, and an overview of this work has been described in.

The general NGN architecture is typically described in terms of functional blocks or components that are used in combination to enable service providers to support a range of multimedia services. A high-level, generic view of this approach is shown in Figure 1, based on the Technical Report developed by the ITU-T NGN Focus Group (FGNGN). More detailed representations of the NGN have also been developed by the ITU-T and other bodies such as ETSI TISPAN and ATIS, etc. in order to specify the functions and interfaces for standardization.