scope:

This Recommendation specifies the high-level requirements for the development of a set of ITU-T Recommendations which will constitute NGN.

The high-level requirements and related capabilities specified in this Recommendation are aligned with the general goals and objectives captured in [ITU-T Y.2001] and are based on the objectives of NGN release 2 [b-ITU-T Y.Sup-7].

The requirements are mainly provided from a high-level perspective, and are not intended to constitute precise functional requirements for the different NGN entities.

More detailed requirements are outside the scope of this Recommendation.

It is recognized that a specific realization of NGN may be constituted by an arbitrary set (or superset) of services supported in NGN and of capabilities as specified in this Recommendation.

NOTE 1 - Text taken from [ITU-T Y.2201] uses blue font. Also, Appendix I identifies the main differences in terms of high-level requirements and capabilities between this Recommendation and [ITU-T Y.2201].

NOTE 2 - It is also required to consider how NGN can contribute to energy savings. However, studies for this topic are ongoing in ITU-T Study Group 5 based on the output from the ITU-T Focus Group on ICTs and Climate Change. So requirements from energy savings aspects are for further study in this Recommendation. For the output from the ITU-T Focus Group on ICTs and Climate Change, please see [b-ITU-T Climate].