Regulation in a convergent future: numbering and number portability

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December 19, 2005

...the market will not work effectively if consumers in a converged world are not able to move seamlessly from one service provider to another

Fixed-mobile convergence (FMC) raises a number of important questions for regulators with respect to both numbering plans and number portability. The fundamental issue is that the market will not work effectively if consumers in a converged world are not able to move seamlessly from one service provider to another.

Numbering plans

Many national regulators administer a numbering plan for telecoms services. With convergence, there is a move away from the traditional technology-specific numbering plans to a technology-neutral identity management system, allowing a single contact point to be able to access a range of communications devices.

One such system is the ENUM protocol, which maps a telephone number to a Uniform Resource Identifier (URI) that can be used to contact a resource associated with that number. The URIs are based on a Domain Name System (DNS) architecture.

National ENUM trials are being held, or are scheduled, in Australia, Austria, China, France, Germany, Korea, the Netherlands, Poland, Singapore, Sweden and Switzerland, while in the United States NeuStar – the company that manages the North American telephone numbering databases – is conducting an ENUM trial using test telephone numbers.

Case study: Australia

In December 2003 the Australian Communications Authority (ACA) launched a project to understand the impact of the future communications environment on regulation. The final project report discusses many different types of convergence, including fixed-mobile, telecommunications and broadcasting, IT and consumer electronics, PSTN and VoIP. The ACA believes that there is a limited future for separate fixed and mobile numbering plans:

Numbering plans are likely to continue operating for the next 10 to 15 years, but will start to decline in importance in the near future relative to electronic addressing, authentication and verification of identity. Fixed - mobile convergence may mean that separate national numbering plans are unlikely to be sustained over the longer term. [ACA (2005) Vision 20/20: Future scenarios for the communications industry – implications for regulation, p45].

The ACA expects that the current Australian numbering plan has a lifetime of “perhaps five to ten years, at most”.

During the twelve-month Australian ENUM trial, which commenced in June 2005, the ACA is assessing the long-term viability of the system, with particular emphasis on issues such as privacy, security, service availability and numbering system robustness.

While the ACA is supporting the ENUM protocol, it recognises that developments in open source interconnectivity systems will need to be monitored, as these may provide superior solutions.

Number portability

Technological and market developments, particularly in relation to fixed-mobile convergence, are driving the need to review number portability.

Common numbering plans, such as the ENUM protocol described above, will greatly facilitate the challenges of porting a number between fixed and mobile networks, however there are several issues that regulators must still address.

Case study: France

In the final report on its public consultation on number portability , the French regulator – Authorité de Régulation des Télécommunications (ART) – found that different pricing methods would detract from pricing clarity for portability between the fixed and mobile networks. The price the caller pays for a call should not be affected if a number has been ported from a fixed to a mobile network, otherwise this would generate pricing uncertainty. Furthermore, there may be a significant deterrent to porting numbers if a charge is incurred for receiving calls on a ported number.

ART notes that technical solutions for number portability, such as the development of common numbering databases for use by both fixed and mobile operators, or “Intelligent Architecture” methods, are required to prepare for convergence.

In a convergent future porting charges will be symmetrical, that is the price to port a mobile to a fixed number should be the same as that to port a fixed to a mobile number. As at 2004, several of the European Union countries, including France, have comparable charges for both fixed and mobile number porting. Where asymmetric charging exists – for example in Belgium, Finland, Spain and Sweden – mobile porting charges are lower than those for fixed porting.


A convergent future will bring many challenges for regulators. It is clear from the projects already being undertaken by regulators that:

  • FMC is a significant issue in the planning of future telecommunications regulations
  • FMC is not viewed by regulators as the objective of regulatory change, rather it is a possible result of regulatory change.

We believe that it is preferable that regulators anticipate potential areas of market failure, yet develop a sufficiently flexible regulatory environment to allow competitive forces to act as the prime delivery mechanism for services at prices that are in the best interests of the consumer.