Next-Generation Network (NGN) refers to a packet-based network and it can be used for both telecommunication services as well as data and it supports mobility. It is able to make use of multiple broadband capabilities, especially Quality of Services (QoS) enabled transport technologies where the service-related functions are independent of the underlying transport-related technologies.
The main goal of Next Generation Network (NGN) is to serve/work as a replacement of Public Switched Telephone Network (PSTN) and Integrated Services Digital Network (ISDN).
Nowadays there exist different networks for different purposes like voice, data, and all sorts of video. The telephony, Internet, and cellular networks refer to different domains and each has its own protocol and services. The idea behind the Next Generation Network (NGN) is that one network that transports all types of data and provides services in the form of packets similar to those which is used on the Internet.
Commonly NGNs are built around Internet Protocol (IP). That’s why sometimes NGN is referred to as an all-IP network to describe the transformation towards Next Generation Network (NGN).
International Telecommunication Union Telecommunication Standardization Sector (ITU-T) defines Next Generation Network (NGN) as a packet-based network that provides telecommunication services to users and it uses multiple broadbands, QoS enabled transport technologies. NGN is a generalized mobility approach and it allows consistent and all over-provision of services to users.
Fundamental characteristics for defining NGN :
Packet-based transfer.
Separation of control functions for bearer capabilities, call/session – service.
Decoupling of service and network, and provision of open interfaces (I/F).
A wide range of services like (Real-Time(RT)/ streaming/non-Real Time (RT)/ multimedia).
Interworking with legacy networks via open I/F.
Support of Generalized mobility.
Support to unrestricted access by users to different service providers.
Services supported in NGN :
Data communication services.
Multimedia Services.
Public interest services.
Public Switched Telephone Network (PSTN)/Integrated Services Digital Network (ISDN) simulation services.
Public Switched Telephone Network (PSTN)/ Integrated Services Digital Network (ISDN) emulation services
Next-Generation Network Layer :
In Access Layer, different types of media gateways that support connection to and from access network with the core network are included.
The Core network layer is network handling converged services based on Internet Protocol (IP). The Control layer works as a call server. It provides call control functions also provides control of a media gateway.
The service layer is an IT platform that creates a service creation environment extending its functionality in order to cover new network scenarios as an intelligent network.
The below figure illustrates Next Generation Network (NGN) Layers as follows.
This basic reference model separated the Transport layer (Access and Core) from the Service layer. In short Access Layer elements handles different media gateways.
Core Layer handles networks based on IP. Control Layer handles call control functions and control of media gateways. Service Layer is an IT platform that plays the role of an Intelligent Network Service Creation Environment.
