Next Generation Networking

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Next Generation Networking (NGN), also referred to as Next Generation Network Architecture (NGNA), is a broad term for a certain kind of emerging computer network architectures and technologies. It generally describes networks that natively encompass data and voice (PSTN) communications, as well as (optionally) additional media such as video.

The general idea behind NGN is that all information is transmitted via packets, like the Internet; packets are labelled according to their type (data, voice, etc) and handled differently for Quality of Service (QoS) and security purposes by traffic management equipment. In a NGN there is a more defined separation between the transport (connectivity) portion of the network and the services that run on top of that transport.

Next Generation Networks are based on Internet technologies including Internet Protocol (IP) and Multiprotocol Label Switching (MPLS). At the application level, Session Initiation Protocol (SIP) seems to be taking over from ITU-T H.323.

According to ITU-T the definition is:

A Next Generation Network (NGN) is a packet-based network able to provide services including 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.[1]

NGN's architecture allows decoupling the network's transport and service layers. This means that whenever a provider wants to enable a new service, they can do so by defining it directly at the service layer without considering the transport layer - i.e. services are independent of transport details.

For voice applications one of the most important devices in NGN is a Softswitch - a programmable device that controls Voice over IP (VoIP) calls. It enables correct integration of different protocols within NGN. The most important function of the Softswitch is creating the interface to the existing telephone network, PSTN, through Signalling Gateways (SG) and Media Gateways (MG). However, the Softswitch as a term may be defined differently by the different equipment manufacturers and have somewhat different functions.

One may quite often find the term Gatekeeper in NGN literature. This was originally a VoIP device, which converted (using gateways) voice and data from their analog or digital switched-circuit form (PSTN, SS7) to the packet-based one (IP). It controlled one or more gateways. As soon as this kind of device started using the Media Gateway Control Protocol (MGCP), the name was changed to Media Gateway Controller (MGC).

A Call Agent is a general name for devices/systems controlling calls.

The IP Multimedia Subsystem (IMS) is a standardised NGN architecture for an Internet media-services capability defined by the European Telecommunications Standards Instititue (ETSI) and the 3rd Generation Partnership Project (3GPP).

In UK another popular acronym was introduced by BT (British Telecom) as 21CN (21st Century Networks, sometimes mistakenly quoted as C21N) -- this is another loose term for NGN and denotes BT's initiative to deploy and operate NGN switches and networks in the period 2006-2008 (the aim being by 2008 BT to have only all-IP switches in their network)

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