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Home : ITU-T Home : Study Groups : Study Group 2
Question 1/2 – Application of numbering, naming, addressing and identification plans for fixed and mobile telecommunications services
(continuation of part of Q.1/2)


The Question has traditionally maintained an extensive list of projects. With the continuing growth in new public services, networks, concepts and capabilities, the list of projects is not expected to diminish - numerous new telecommunications services require unique numbering, naming, addressing and identification capabilities that have been developed by this question.

With the anticipated development of new networks (referred to as Next Generation Networks) and their yet to be defined capabilities, it may be necessary to address new telecommunications services which might require unique numbering, naming, addressing and identification capabilities. Aspects of mobility including those relevant to the mobile cellular radio systems global and regional satellite networks and other similar requirements need to be considered. It is anticipated that such capabilities have the potential to be significantly different from those applicable to currently deployed (legacy) networks, yet it is essential that they interwork fully with this legacy environment.

In a competitive global telecommunications environment, the importance and controversial nature of numbering, naming and addressing issues often cause their study to be contentious and lengthy. The nature of these studies, consequently, results in not only a large list of issues, but also the need for significant time for the resolution of each. This nature of the studies is also not expected to diminish.


The Question will deal with the issues detailed under Tasks below.

Project number Topics and rationale Target completion date
1 Maintenance of existing E-series numbering related Recommendations

Rationale: This project reviews and revises, where and when appropriate, the existing ITU-T numbering, naming, and addressing Recommendations of the E-series and F-series, e.g. E.118, E.129, E.164, E.164.1, E.164.2, E.164.3, E.168, E.168.1, E.169, E.169.1, E.169.2, E.169.3, E.190, E.191, E.191.1, E.193, E.195, E.212, E.213, E.214, E.217, E.218, E.370, E.910.

This project will ensure that these Recommendations are updated to reflect the current circumstances of the global telecommunications industry and regulatory environment taking into account NGN and IP-based networks. As an example, several recommendations were revised and updated during the last Study Period. This project also addresses requests for resources described in Recommendations such as E.212, E.164 or E.118 resources not covered in any of the projects below.

2 Mobile (including SNAC) numbering issues

Rationale: This project studies the sometimes unique numbering and addressing requirements of the mobile sector of the telecommunications industry. These studies are periodically introduced by mobile service providers for timely resolution.

Current Inmarsat is consolidating its network and access arrangement into one E.164 Country Code - there are currently four such codes assigned to Inmarsat. The project is titled Single Network Access Code (SNAC) and the Q.1 question has an agreement with Inmarsat regarding the time schedule for this project and the resulting return of the four ocean zone country codes; the four ocean region codes are due to be relinquished by Inmarsat by 01 Jan 2009, after which this part of the project should be complete.

3 UIFN/UIPRN/UISCN registrar coordination

Rationale: The Question maintains the Recommendations regarding the administration of Universal International Freephone Numbers (UIFN), Universal International Premium Rate Numbers, Universal International Shared Cost Numbers and ITU-T IND ATM End System Addresses (ITU-T AESAs)

Under this project, the question will consult on an ongoing basis with the Registrar to resolve issues, relative to the above resources and any new resources created in the future, presented by the industry and the Registrar.

4 Request for numbering resources for new telecommunications services

Rationale: When new global or regional services are developed and proposed for implementation, they often request/require global numbering resources. This project receives and determines such resource requests.

This question will receive, study, and resolve such anticipated requests. Previous examples of such requests include UPT, UIFS, USCS, GMSS, RMSS, ETNS, etc.

5 Global evolution of naming, numbering and addressing requirements for telecommunications services

Rationale: This project will undertake to study the potential evolution of global numbering, naming, addressing and identifier methodologies to accommodate current and future services, technologies, capabilities, and architectures. This work relates closely to the work in Projects 6 and 14.
A global understanding of these future methodologies and their evolution would be of significant value to telecommunications network operators, service providers, vendors, planners, forums, and standards bodies worldwide.

The new project would initially develop a uniformly-acceptable definition for and an understanding of numbering, naming, addressing and identifiers. Once the definitions are agreed upon, the project would then study and document the projected evolution of numbering, naming, addressing, and any other potential identifier methodologies and its convergence with IP-based systems/networks including NGN.

Specifically in relation to NGN it is anticipated that there may be a need to revisit issues of personal and terminal mobility, including the concepts of a single terminal being used by multiple subscribers. Personal Mobility might include the idea of a subscriber being able to move between terminals whilst communications are active and in progress and also in the time periods between instances of active communications.

With regard to geographic location it is anticipated that NGN may have additional or different requirements for both terminal and subscriber geographic location compared with existing and legacy systems. This could give rise to the requirement for new numbering and identifier resources or the expanded use of the current E.164 and E.212 resources.

Undertaking studies into the “future of numbering” based upon Identity Management and other similar requirements.

6 Naming, numbering, addressing and other identifiers for interworking between E.164 numbering plan-based networks and IP address-based networks

Rationale: Convergence of the existing telecommunications networks, both fixed and wireless, with the IP address-based network requires the continuing development of naming, numbering, addressing and other identifier mechanisms to support this convergence.

The project identifies requirements and develops solutions for the interworking between the E.164 numbering plan-based networks and IP address-based networks. The development of a solution includes, but is not limited to, the identification of the E.164 resource, the determination of how these resources will be used and administered, the determination of the E.164 addressing scheme required to support this type of interconnection, and the determination of which, if any, E.164 resources will be made available to IP address-based networks.

In addition, this project will consider identification of identifiers with respect to the longer term goal of convergence of the naming and addressing schemes used in international telecommunications networks.
The objective is a Recommendation(s), as appropriate, containing the results of the above work.

7 Implementation and Activation of E.164 Numbering Resources

Rationale: The growth of new and existing telecommunications services, as well as the quantity of network operators and service providers due to the evolution of competition in the telecommunications industry, has resulted in the introduction of numerous new geographic and non-geographic numbering resources domestically and internationally. In order for these resources to be activated effectively, new methods are required to increase awareness and implementation of the resources.

This project will study potential new awareness and implementation methods as appropriate and, as a result of the study, will publish these methods in a new E-series Recommendation.

8 Number portability

Rationale: Update the existing Number Portability Supplement to include the necessary technical requirement for the introduction of number portability, including with respect to IP address-based networks.

9 ENUM Interim Procedures

Rationale: During the last Study Period (2000-2004) the Question approved interim procedures for the delegation of E.164 Country Codes and E.164 CCs + ICs into the Domain Name System (DNS). It has been agreed that these procedures will be reviewed based on any contributions received during a full Study Group meeting in order to ensure that the procedures are updated and approved as needed.

10 ENUM Administrative Issues

Rationale: Issues are arising that deal with the process and procedures for delegation of E.164 international numbering resources and the Question is developing individual Recommendations for E.164 Country Codes, E.164 CCs + ICs, E.164 CCs + GICs, and Global Services. The Question will finalize the recommendations dealing with each category of E.164 international numbering resources (e.g., E.A-ENUM, E.A-N/GoC, E.A-GSVC).

11 Criteria for assignment of E.212 resources

Rationale: This project will study whether it is appropriate to develop and describe high-level principles for the assignment, and reclamation of E.212 mobile country codes. The principles, if developed, will be the basis for the effective and efficient utilization of the available E.212 numbering resources.
If the study determines that principles should be developed, the project will develop the principles for the assignment, and reclamation of E.212 mobile country codes. This may include expanding the scope of the use of E.212 resources to cater for the needs of developing infrastructures such as NGN.

12 Opening access to E.164 resources

Rationale: Develop the necessary guidelines and procedures for propagation of information related to the introduction of new E.164 numbering series.

xx Other projects as they are proposed and approved

Rationale: A significant amount of Q.A work throughout a study period is the result of new issues presented by Q.A Collaborators. These issues typically resulted in numerous new projects defined and approved during the previous study periods.

Q.A will continue to define, study, and resolve new issues through the approval of additional projects.



Within ITU

  • ITU-T SG3 on tariff and accounting principles, telecommunication economic and policy issues
  • ITU-T SG17 on Identity Management, security, languages and telecommunications software
  • ITU-T SG11on signalling requirements and protocols
  • ITU-T SG13 on NGN
  • ITU-D SG2

With other groups

  • ETSI
  • IETF
  • 3GPP
  • GSMA
  • Relevant international forums/organizations


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Updated : 2009-04-23