The NGN concept is mainly used in two ways: 1) A broad concept encompassing the whole development of new network technologies, new access infrastructures and even new services, and 2) A focused concept of specific network architecture and related equipments, with one common IP core network deployed for the entire legacy, current and future access networks. The first definition is so broad that in a sense it covers the whole current chapter on technological trends. The second definition relates to the transition path towards a converged IP-based core and access network. In this report, the concept of NGN denotes the second definition. Here we distinguish between the Next Generation Core Network (NGCN) and Next Generation Access Network (NGAN). The NGCN is about the new switching, gateways and transmission equipments in the core network, enabling several access networks to use the same core network. The NGAN is about new access networks, like deployment of optical fibers, and the challenges derived from that.
ITU defines NGN as "a packet-based network able to provide 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 enables unfettered access for users to networks and to competing service providers and/or services of their choice. It supports generalized mobility which will allow consistent and ubiquitous provision of services to users".[1] In this definition there is a major emphasis on one of the main characteristics of IP platforms namely the separation of network and service layers.
NGN is about the transition from current dedicated voice (and radio/TV) networks to the IP-based networks. From a technology efficiency point of view this is a natural development of all network technologies. However, there are a number of problems connected to the overall organization of the NGN platforms, which are subject for discussions amongst regulators today. One of the main issues is the interconnection model which will be used in the NGN. Will this, for example, be dominated by the IP interconnection models like peering and transit, or will the PSTN interconnection and tariff regime be modified and used in the future NGN platforms?
In this section first the NGCN and then the most important NGANs are described and organised in two major categories, Fixed and Wireless:
Fixed:
Wireless: