What is Next Generation Networks (NGN)
NGN are the systems based on emerging packetization technology of IP which is leading to convergence of networks, services and markets and enhancing efficiency and flexibility by following the layered approach for separation of Infrastructure, Service Control and Service Provision function. NGNs offer service providers and operators a converged, efficient and flexible IP-based platform which can evolve in a modular and flexible manner to create, deploy and manage innovative unified and application services.
As TDM technology, which is Circuit Switched (Connection-Oriented) and hence inefficient and inflexible is being phased out, the IP- based NGN is taking charge. In NGN domain various network elements will be: Softswitch, IMS (IP Multimedia Subsystem), Media Gateways, Service Control servers, Application servers, routers and Transmission links and Broadband Access .
NGN is a layered architecture consisting of Transport, Service Control and Application layers distributing intelligence at every layer. The underlying Packet transport and media infrastructure is grouped under Transport layer which also inter-works with circuit- switched (PSTIN) network through media Gateways so that existing networks need not be scrapped. The Service Control layer consisting of Softswitches, Media Gateway Controllers and IMS performs the functions of control, authentication, accounting, maintaining QOS, security and network management. The Application layer makes use of capabilities provided by other functional layers to provide muliti-media services and applications.
The definition of NGN as per ITU is as following:
“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 in which service-related functions are independent from underlying transport-related technologies; It offers unrestricted access by users to different service providers.
What are these networks designed to do? From co-existing with PSTN, to be agnostic to access technology, they support quad-namely voice, data, video and mobile services including quality of service requirements. The architecture is based on open standard for the networks to be versatile with separation between service provision and underlying infrastructure so that operational license holders have flexibility and could accommodate different content to serve the customers with innovative and multi-media services.
NGN has not only to take care of every existing and new multimedia service but also cater to different enduser devices like computer, laptop, fixed line telephone or mobile handset or TV. Such networks are obviously going to be the networks of the future as the handset delivers not only voice and data but also video, mobile TV, mobile e-mail and all other unified services. This has become the big story in communication now, a change from VOIP to EOIP or Everything over- Internet Protocol;
PSTN migration to NGN
The evolution of PSTN to NGN would be determined by customers and services. Instead of merely providing broadband, it promises new services to end-users. NGN must build on the strength of both the telephony and the internet service models. Access modernization is key in this evolution but state of the art PSTN solutions of today can evolve and stay part of the future NGN systems to preserve investments. Access for instance could be through high sped broadband provided through ADSL, VDSL, and Wi-Max, FTTH or PLC or all of them. Carrier Ethernet and IP-MPLS have become preferred transport modes.
Advantages of NGN
NGN makes use of best of both the worlds (flexibility, efficiency & Innovativeness of IP and QOS, Security, Reliability, Customer-friendly features of proven PSTN)
For service providers these provide many advantages. The integrated and efficient packet based technology reduces capex. Transmission costs are lower, greater power saving, less space requirement and less O&M costs while there is also ability to offer wider range of services at faster speed. Yet another advantage is personal service customization and management. Instead of maintaining different networks for different services, the single network alone need be managed.
Subscribers also benefit as call charges are reduced, they could choose multiple service providers to get maximum advantage of competitive offers and take advantage of single billing for all services of voice, data, video and mobile.
Fixed Mobile Convergence (FMC)- A Compelling NGN Application Amajor development due to the versatility of NGNs is that it is now possible to have fixed-mobile convergence for the benefit of the users and also to conserve the precious licensed spectrum. In the context of decline in fixed line usage and saturation in mobile, there could be more harmonious division of time between the two benefiting the entire system. As broadband becomes ubiquitous and cost effective and mobile handset is turned into a multi-band palm-held computer, the advantages of increased use of FMC could be easily seen.
NGN Deployment Scenario
Several operators are now realizing NGN as the future and are evolving towards it. Obviously existing PSTN cannot be scrapped overnight but migration has to be initiated the sooner the better. BT in UK is one such operator. Key milestones towards NGN migration in what is termed as 21CN began with the initiation of transition in 2005, completing the transformation into NGN by 2011.
Many countries like UK, Japan, Korea Malaysia, Italy, Singapore, Australia, New Zealand, Vietnam and China have decided to migrate to NGN. The incumbent operators there are going for NGN and replacing their existing network to IP –based in a time bound manner. This is being done to beat to competitors and new entrants on the technology front and being able to provide new value added services, cut down on Opex as well as to make the network future-proof.
Regulatory challenges for migration to NGN
NGN capabilities are blurring the differences between multiple services and traditional boundaries between local access and long distance operators are vanishing. Regulators are now faced with ongoing technological developments causing drastic impact on the telecom scenario forcing a re-look at the service based licensing and geographical area based regulatory regime including numbering systems. They have to determine who exclusively telecom operator is and who value added service provider is when operators are also becoming value added service providers and niche operators are connecting to large networks.