Next Generation Networks (NGN)
The term is used by equipment suppliers, private network service providers, public network operators, standardisation bodies, telecommunications sector analysts, policy-makers and regulators. In each case, it anticipates the use of intelligent devices in the hands of users, with limited reliance on intelligence at the core of the network.
A renewed public network :-
It is used to describe the replacement of the switching system at the core of the public telecommunications network. Carriers and manufacturers of network equipment use the term in this narrow sense when discussing regeneration of the current public switched telephone network (PSTN). Intelligent devices at the network edge will enable users to exploit the capabilities of the renewed network.
The concept of network layers :
More broadly, it describes a conceptual approach to the fixed and mobile telecommunications networks of the future in which network elements are viewed as layers. For example, the higher layers in the diagram can accommodate any number of service providers, and the lower layers describe the role of the carriers and other providers of network infrastructure.
Advanced private networks :
The most advanced “next generation networks” available now are not public but private networks. Corporate networks provide business users with a menu of advanced voice and data services, high speed internet and intranet services, video-conferencing, and specialised services to support electronic transactions.
Software-based services :
Sometimes discussion focuses on the user’s access to software that can provide voice and multimedia services. The internet already provides access to such services. At a more sophisticated level, “middleware” such as directories and authentication services become vital for electronic transactions.
Multiple services and service providers :
Regardless of how the term is used, next generation networks usually imply multiple services using the same network. These services may be offered by a number of providers who do not necessarily own or manage the physical infrastructure (the ‘carriage’ layer) of public networks.
Drivers and enablers :
Packet switching and IP – the enabling technology :
The internet is based on a transmission protocol called the Internet Protocol (IP). IP enables data to be broken into packets, transmitted, and then reassembled at the destination. The technology is a form of packet-switching. This is contrasted with circuit-switching, which was designed for voice communications and remains the primary technology employed in the PSTN. Circuit-switched networks rely on signals sent down an electrical circuit created between the telephone exchange and the telephone, with signals for particular applications (eg voice services) being assigned a dedicated channel (circuit) on the network. IP technology is now being incorporated into the telecommunications network, and can be considered the key enabling technology for next generation networks. When devices in the core of the network (exchanges, signal concentrators, central switches) need to be replaced, they are being replaced with IP-based devices. Carriers have the opportunity to consolidate switching services in a smaller number of centres with packet-switching technology that can carry large volumes of integrated traffic, including multimedia and data services in addition to voice. Carriers therefore expect to consolidate services and traffic, and save money on carriage, network management, maintenance and service costs.
Broadband access :
The demand for broadband is a driver for the development of next generation networks, expanding the transmission capacity available to consumers and giving them the opportunity to use internet-based voice and multi-media services. Carriers converting to packet-based networks hope to take advantage of this demand and to provide a wide variety of innovative services with a high level of service quality and security.
Mobile access :
Mobile users already enjoy more sophisticated services than fixed telephone customers, with multi-function phones that also function as cameras, games platforms and micro-computers. Mobile internet and mobile television services are developing rapidly.