Discussion Papers

Stefano Lucidi, Ulrich Stumpf:

Implications for the management of numbering due to the internationalization of telecommunications networks and services

No. 393 / December 2014

(Full version only available in German)


The availability of adequate numbering resources is a crucial pre-requisite for the development and growth of telecommunication markets and services. New business models, such as VoIP and machine-to-machine (M2M), change the demand for numbering resources and are challenging national regulatory authorities worldwide with the task of adapting the existing numbering management.

  • E.164 is a general format for international telephone numbers and according to the ITU-T recommendation E.164 defines an international public telecommunication numbering plan for the world-wide public switched telephone network (PSTN).
  • E.212 are International Mobile Subscriber Identity (IMSI) numbers and according to the ITU-T recommendation E.212 used to identify the user of a cellular network. The E.212 numbering standard is a unique identification associated with all cellular networks.

The study shows the implications of these developments for the national numbering administrations. In several countries a bottleneck especially for MNCs of E.212 is expected due to the development of new business models. With regard to E.164 numbers, a possible extraterritorial application of the numbers is at the forefront of discussions, because internationally active M2M and VoIP providers are eager to offer their services simultaneously in several countries. To meet these challenges there are different courses of action for national and international authorities dealing with numbering management.

To counter the risk of a number shortage of MNCs in the near future, a technical proxy solution, as it was introduced in the Netherlands recently, can be realized without larger regulatory adjustments in the market. Alternative solutions require more effort in terms of technical and regulatory adjustments or even need a harmonization on an international level.

E.164 numbers are, although not explicitly mentioned in the recommendations of the ITU, designed for a geographical application. Numbering plans and allocation rules meet the needs of national markets, and the laws of different countries vary significantly. A general authorization for using E.164 numbers on a permanent extraterritorial basis is accompanied by significant legal and technical obstacles. An adaption of existing rules to allow an extraterritorial use of E.164 numbers require a global consensus via the ITU.

In the medium to long-term a breakthrough of the Embedded SIM (eSIM) is expected, which will have effects on the use of E.212 and E.164 numbers. In the end of 2013 common technical standards for the use of eSIM were adopted by the GSMA. The use of eSIM prevents operator-lock-in effects for third parties such as M2M providers and facilitates the cross-border use of for example M2M applications. In the case of Connected Cars, for example, a cross-border use would be conceivable through eSIM without incurring international roaming charges.

In case of a widespread use of eSIM, the allocation of E.212 and E.164 numbers could be conducted more efficiently. In case of a temporary use of E.212 and E.164 numbers, the overall number of unused capacities could be reduced.

Overall, major adaptions of existing rules regarding the management of E.212 and E.164 numbers will not be necessary under these circumstances. In the short to medium term, national regulatory authorities, if required (e.g. in the case of number scarcity of MNCs) could take action and adapt the regulatory framework appropriately. In the light of the further spread of eSIM and a possible future migration to IPv6, national regulatory authorities should continue to monitor market developments in order to adapt regulatory measures when necessary.

Discussion Paper is available for download.

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