Next Generation Network (NGN)
The Next Generation Network (NGN) is a phrase that refers to the network that is being developed to replace the PSTN network commonly used today to provide international telecommunication service.
The NGN is essentially a managed IP-based (i.e., packet-switched) network that enables a wide number of multimedia services. Among those are VoIP, videoconferencing, instant messaging, email, and all other kinds of packet-switched communication services.
The ITU has defined the NGN in ITU-T Recommendation Y.2001 as follows:
Next Generation Network (NGN): a packet-based network able to provide telecommunication services and able to make use of multiple broadband, QoS-enabled transport technologies and in which service-related functions are independent from underlying transport-related technologies. It offers unrestricted access by users to different service providers. It supports generalized mobility which will allow consistent and ubiquitous provision of services to users.