ITU-T Recommendations

Supplement 2 to Recommendation ITU-T E.164 defines standard terminology for a common
understanding of the different aspects of number portability within an ITU-T E.164 numbering
scheme. It identifies numbering and addressing formats, call flows, network architectures and routing
approaches that will provide alternative methods of implementation. It also proposes some examples
of the administrative and operational processes required for the successful implementation of number
portability.