|Why NGN? |
The NGN concept takes into consideration new realities in the telecommunication industry characterised by factors such as: the need to converge and optimise the operating networks and the extraordinary expansion of digital traffic (i.e., increasing demand for new multimedia services, increasing demand for mobility, etc.).
Background: ITU-T’s NGN Work
In 2003 a Joint Rapporteur Group bringing together experts from across all Questions of Study Group 13 was formed. The main subjects studied by the Joint Rapporteur Group on NGN (JRG-NGN) were: NGN requirements, the general reference model, functional requirements and architecture of the NGN, and evolution to NGN. The JRG-NGN produced two fundamental Recommendations, viz. Y.2001, General overview of NGN and Y. 2011, General principles and general reference model for next generation networks.
In order to continue and accelerate NGN activities initiated by the JRG-NGN, ITU-T established a Focus Group on NGN (FGNGN) in May 2004. Focus Groups provide an effective and rapid response mechanism for progressing the work of the ITU-T. The FGNGN addressed the urgent need for an initial suite of global standards for NGN. The FGNGN’s mandate was extended through November 2005 as it was clearly attracting significant participation and input from the membership.
Present: NGN Global Standards Initiative (NGN-GSI)
The results of the FGNGN (Release 1) provided the building blocks on which the world’s systems vendors and service providers can start to make the shift to NGN. Since the creation of FGNGN there has been an intensive schedule of meetings, about every two months, but more importantly there has been growing momentum in the work, and growth in participation and the number of contributions. Now this work is carried forward by ITU-T’s NGN-Global Standards Initiative (NGN-GSI), which encompasses all NGN work across ITU-T Study Groups. It has been implemented by co-located meetings of concerned Study Groups and Rapporteur Groups from the various study groups to jointly progress the work under the auspices NGN-GSI.
NGN-GSI Objectives and Goals:
NGN Study Topics
- to address the market needs for NGN standards
- to produce global standards for NGN
- to further strengthen the ITU-T’s leading role amongst the groups in NGN standard work
- to keep visibility of the work spread between different technical groups in ITU-T
Over the few years the market drive for NGN standards has firmed up and a number of operators have announced implementation plans for the transition to IP-based networks.
An implicit part of the agreement to close the NGN Focus Group was that steps would be taken to maintain the momentum that had been built up by the Focus Group in order to provide the global standards to underpin these plans. This has been implemented by co-located meetings of the concerned study groups and their Rapporteur groups to jointly progress the work under the auspices of the NGN-GSI
ITU-T activities are related to the establishment of architectures, interface specifications, and implementation guidelines in the form of ITU-T standards (Recommendations) for the realisation of NGN.
Evolution of Networks to NGNNGN Work Planning and Coordination
The evolution of networks to NGNs must allow for the continuation of, and interoperability with, existing networks while in parallel enabling the implementation of new capabilities. Since the realisation and deployment of the NGN will be an evolutionary process, and not all networks will start from the same point, it is necessary to describe a variety of approaches.
The high capital investment in the PSTN (public switched telephone network) means it must be one of the main work areas for studying evolution to the NGN. The resulting outputs describe possible ways of evolving the PSTN to become an NGN. These outputs provide steps for evolution of transport, management, signalling and control parts of the PSTN to the NGN. Other starting points, notably existing public land mobile networks (PLMNs), and associated transition scenarios are also under study.
QoS (Quality of Service)
The basic criterion for QoS evolution is ‘subjective user satisfaction’, e.g. speed, accuracy, reliability, and security. This involves identification of parameters that can be directly observed and measured at the point at which the service is accessed by users and network providers. Flexibility within the global end-to-end NGN architecture is essential to allow for each recognised operating agency’s different regulatory environment, service offerings, geographic span, and network infrastructure. These factors need to be taken into account when agreeing on parameters for, and levels of, QoS for NGN.
Considering that the NGN will involve a broad series of protocols (including various profiles) at both service and network levels, it is essential to ensure interoperability between different systems and networks.
Security is as crucial to the NGN as it is in today’s network environment. The very wide scope of this topic, combined with the number of SDOs (standards development organisations) already involved, underlines the strategic importance of this subject. Within the NGN, security issues interrelate with architecture, QoS, network management, mobility, charging and payment.
Security studies in NGN are addressing:
- a comprehensive security architecture for NGNs
- the preparation of NGN operational security policy and guidelines
- NGN security protocols and APIs (application programming interface)
NGN will give users and devices the ability to communicate and to access services irrespective of change of location or technical environment. The degree of service availability may depend on several factors, including access network capabilities, service level agreements between the user's home network and visited networks, etc. It includes the ability to communicate from various locations using a variety of terminal equipment, with or without service continuity while in transit or while changing access means. This includes recognition of the need to converge the previously distinct worlds of fixed and mobile telecommunications into a coherent whole.
Service Capabilities and Architecture
Work in this area will continue to:
Backward compatibility with and the evolution from existing services and systems will be studied in order to meet the needs of end users and service providers.
- address the telecommunication service capabilities that the NGN should provide, maintaining separation between services and the networks they run on; and
- develop a suitable service architecture focused on the interfaces to support different business models and seamless communication in different environments.
Study Group 13 is developed a Release plan for ITU-T NGN Recommendations indicating where the work is being, or to be done and by when. NGN Focus Group deliverables were passed to Study Group 13 for processing as draft Recommendations (where appropriate) by Study Group 13 or by other study groups depending on the subject.
In addition a web-based NGN Project Management Tool, developed with the support of a voluntary contribution from Siemens, aims to provide an overview of the NGN work going on across the standardization world. Essentially, it acts as a repository of NGN information from ITU and other SDOs. A key feature of the tool is the ability to track work progress and see the latest versions of documents.
Ongoing involvement of other SDOs and regional standards organisations in the NGN planning and standards development activities is essential.