NGNs

NGNs, or Next Generation Networks, are packet-based telecommunications networks that deliver voice, data, and multimedia services over IP-based infrastructure. They aim to converge networks previously separated by technology, enabling end-to-end service delivery regardless of access method. The concept gained prominence in standardization efforts by ITU-T and other bodies in the late 1990s and 2000s.

Key architectural principles include decoupling of the service layer from the transport layer, and the use of open, interoperable signaling protocols. An NGN typically features an IP core (often using MPLS), edge and access networks, and a service layer that may include softswitches, media gateways, session border controllers, and an IP Multimedia Subsystem for multimedia services. Signaling and control commonly rely on SIP and related protocols to manage sessions and quality of service across the network.

NGNs support a range of services and capabilities, including voice over IP, video conferencing, messaging, and unified communications over a single network, with programmable networks that allow rapid deployment of new services and applications. This convergence enables more flexible service delivery, scalable capacity, and potential cost efficiencies for providers and users alike.

Adoption and challenges: Many operators migrated from circuit-switched PSTN to NGN gradually, drawn by cost efficiency and service convergence. Challenges include interoperability across vendors, security and privacy concerns, QoS management across diverse access networks, regulatory considerations, and risks associated with retiring legacy infrastructure.

See also: IP telephony, IMS, SIP, VoIP, softswitch.