NGN is a concept for defining and deploying networks, which, due to their formal separation into different layers and planes and use of open interfaces, offers service providers and operators a platform which can evolve in a step-by-step manner to create, deploy and manage innovative services. NGN is therefore a converged IP network.

Traditional circuit switched networks reserve resources from end to end in a fixed inflexible manner with initial development geared towards voice traffic. As a result providers have separate voice and data networks.
Further more, the operations and management of these networks are based on restrictive proprietary systems with limited vendor interoperability.
On the other hand the NGN is a packet-based network where the packet switching and transport elements (e.g routers, switches, and gateways) are logically and physically separated from the service/call control intelligence. This control intelligence is used to support all types of services over the packet-based transport network, including everything from basic voice telephony services to data, video, multimedia, advanced broadband and management applications.The NGN converges the voice and data networks onto a single IP-centric network with great advantages as shown in Fig 2.1 below

The operational and management components of the NGN are based on open standards (NOT vendor specific) these offer seamless equipment interoperability irrespective of supplier. The open nature of this network provides for a significantly
larger arena for new service development.