Number portability for future networks - PTS-ER-2009:7
20/02/2009
Number portability (NP) has been used in Sweden since 1999 and enables end users to retain their telephone number when switching operators.
In 2008, PTS had an operators’ working group, initiated through Nummerforum [Numbering forum], which studied how today’s number portability is to be assured when the existing TDM-based networks move towards the future IP-based networks (e.g. NGN). This is because IP-based networks were not originally designed to process telephone numbers, meaning that these networks must map telephone numbers (through ENUM, for instance) into other identifiers (called ‘URIs’) so that calls can be made to telephone numbers that have been ported.
Two main areas were studied:
- The type of unique NP data to be transmitted between the interconnecting operators via the SIP-based network interface used between IP-based networks.
- The database functions needed for number portability for the IP-based networks to enable the provision of correct supporting data for routing via these SIP-based network interfaces. ‘Database functions’ mean both the current central reference database (managed by SNPAC) and the new ENUM functions which can be used for the IP-based networks. These national ENUM functions will probably become subject to an international ENUM hierarchy.
This preliminary study presents conclusions and identifies work to be continued. The preliminary study is largely based on the results achieved by the participants in the operators’ working group. This group consisted of representatives from TeliaSonera, Tele2, Telenor, TDC, Hi3G, Comhem, Inabler, SNPAC and IT&Telekomföretagen. PTS convened the working group.
The preliminary study is being distributed with an accompanying information letter to all stakeholders with numbering licences, as well as other parties, including the following: .SE, IT&Telekomföretagen, ITS, ISOC-SE and SOF. This is to enable their participation in the continuing work as proposed in section 7 of the preliminary study. This section points out further activities, for example activities to be carried out by ITS and the operators collectively, which it may be appropriate to conduct through the IT&Telekomföretagen association or the NP Forum.
Sections 5.7 and 5.9 in addition to 6.4 to 6.6 and 6.8 summarise outstanding issues identified by the operators’ working group.
Continued activities for PTS include: reviewing regulations and guidelines regarding number portability (PTSFS 2007:7); a decision (reference 00-18205) concerning the obligation of a donor operator to provide reference data; investigating how the technical code routing number for NP should be dealt with in the future and whether PTS should continue to assign such numbering capacity or if another neutral stakeholder should be responsible for this function; and how a framework (not necessarily legal regulation) should be designed to encompass a prospective national ENUM function for number portability.