Numbering & addressing

The International Telecommunication Union (ITU-T) has set out the principles of international public telecommunication numbering for the fixed network in their Recommendation E.164. However, the widespread use of the Internet has meant that it is becoming more and more necessary to unify the E.164 telephone numbering scheme with the addressing schemes used in the Internet.

The Internet uses the Domain Name System (DNS) to provide IP addresses, among other things. Specification RFC 3761 from the Internet Engineering Task Force (IETF) defines ENUM (Electronic Numbering) and provides a suite of protocols to enable callers or networks to determine if a called party can be contacted over the internet. ENUM facilitates the transfer of traffic from public telecommunications networks to the Internet.

RFC 3761 specifies how the DNS can be used for storage of E.164 numbers. More specifically, it shows how DNS can be used for identifying available services connected to one E.164 number.

A Working Group of ETSI technical committee TISPAN has the task of working on issues concerning Numbering, Naming, Addressing and Routeing. It is responsible for:

• Co-ordination of the numbering and addressing issues within ETSI, and contributing to ITU-T Study Group 2
• Addressing and Naming translation
• Representing ETSI at the ENF (European Numbering Forum)
• Collaborating with ERO (the European Radio Office) on European numbering, naming and addressing issues
• Representing ETSI at the ETNS (European Telephony Numbering Space) Steering Committee.