The objective of Recommendation ITU-T E.129 is to specify a methodology that will provide a standardized method for presenting ITU-T E.164 numbers in the national numbering plans (NNPs) of all countries (i.e., each country's application of Recommendation ITU-T E.164). This Recommendation also includes a method to make such NNP information available to all interested parties, as well as timely information on numbering plan changes that influence the routing, charging and accounting of international telecommunication traffic. This Recommendation also helps to collect other information that may be relevant, such as numbers related to important services like emergency services (emergency numbers) and services of social value, as well as information on the implementation of number portability (NP) of ITU-T E.164 numbers.