ENUM

ENUM (Electronic Numbering) is a protocol developed by the Internet Engineering Task Force's (IETF) Telephone Number Mapping Working Group,<re>www.itu.int</ref> which used the Domain Name System (DNS) architecture and protocol to identify available services associated with E.164. ENUM involves the process of creating a domain name from a telephone number and resolving it to an Internet address or Uniform Resource Identifier (URI) using the DNS technology and the hosting of ENUM domain names on the E.164 arpa domain. ENUM is defined in RFC 3761.

History

The International Engineering Task Force created the the Telephone Number Mapping Working Group in 1999. The working group was tasked to determine a DNS based architecture and protocols for mapping a telephone number to a set of characteristics such as URLs, which can be utilize to contact a resource to that particular number. In 2000, the working group published RFC 2916, which discussed ways on using the DNS to determine available services connected to a E.164 number. E.164 is an international telecommunications numbering plan. E.164 numbers are globally unique, language independent identifiers for resources on Public Telecommunication Networks capable of supporting numerous services and protocols.

In 2001, different International Telecommunications Standardization Sector (ITU-T) workshops as conducted in Asia, Europe and North America regarding the administrative issues in implementing the ENUM.

By 2002, ITU-T and the Internet Architecture Board (IAB) approved the interim procedures for ENUM subject to national authorities and end-users approval. ENUM protocol allows consumers to use one number to access numerous terminals and services which include phone, fax, e-mail, pager, mobile telephones, websites or any other services available through an internet addressing scheme. Subsequently the European Telecommunications Standards Institute (ETSI) published its technical specifications for ENUM Administration in Europe. The IAB also assigned the responsibility of delegating the E.164arpa domains to Reseaux IP Européens Network Coordination Centre (RIPE NCC). RIPE NCC assigned the ENUM TLD, 9.4.e164.arpa to the German Interne Community DENIC, which started the ENUM trial on May 21, 2002.

In 2003, ETSI published its technical specifications for Minimum Requirements for Interoperability of European ENUM Trials while the IETF issued final procedures for the ENUM domain and opened the registration of ENUM services through the Internet Assigned Numbers Authority [[IANA]. In 2004, IETF RFC 3761, which specifies Enumservices registration, commercial private ENUM services and public ENUM (E.164.arpa).. The Asia Pacific ENUM Engineering Team (APEET) was established due to the growing interest of the use of ENUM in the region. Its members include JPRS, CNNIC, KRNIC, SGNIC and TWNIC. In 2005, APEET coordinated the ENUM/SIP live trial in Kyoto during theAsia Pacific Regional Internet Conference on Operational Technologies (APRICOT) Conference.

In 2006, the Public User ENUM trial was conducted in the United States for six months between n March 2006 and June 2007. It was sponsored by the Country Code 1 ENUM Limited Liability Company (LLC).

In 2008, the ITU-T approved the ENUM interim procedures for geographic country codes for the Telecommunications Standardization Bureau (TSB).

ENUM Working Group

The ENUM Working Group is responsible in monitoring and promoting discussions and initiatives to develop the advancement of ENUM, the internet resource mapping technology using the E.164 telephone numbers identifiers.

Types of ENUM

There are three types of ENUM, the Public User ENUM, which allows an end user to enter his or her own records in the ENUM registry under the public dumaine164.arpa ehereby the DNS is publicly available to any internet user; Private Infrastructure ENUM is used by a closed group without using the e164.arpa public domain instead, they opt to use the process of creating a domain name from a telephone number and resolving it to a URI to exchange IP traffic; and the third type is the Public Infrastructure ENUM which is assigned by a National Number Administrator which normally delegates a telephone number to a carrier, which in turn assigns the telephone number to an end-user. The Carriers maps telephone numbers to an internal network addresses to enable call routing features which are not publicly available, highly secure and the access is restricted only to other service providers.

Uses of ENUM

Based on a report prepared by the Center for Democracy and Technology, ENUM has several benefits and uses which include:

1. It serves as single number point of contact wherein a single ENUM number facilitates the routing of telephone calls to the internet instead of the regular telephone sytem, meaning it allows numerous access to different types of communication such as fax, cellular phones and many others.
2. It facilitates the transition away from the Public Switch Telephone Network (PSTN) to the internet as the main carrier of voice communication.
3. It can be used as an internal routing within a telephone company's network, for example major telecommunications companies in the United States converts voice calls using VoIP.
4. It serves as a dial access to new internet service providers that allows users to simply dial a telephone number which can be translated using ENUM to a desired internet address for them to be able to access the internet services via cellphone.

ENUM Administration

The International Telecommunication Union (ITU) is responsible in designating which organization will administer or control the implementation of ENUM based on the regulations of a certain country. Every country set their own rules which governs the establishment and control of ENUM records, this means that "called party control" of ENUM is administered by each country.

ENUM Deployment Status

Since its establishment, ENUM has become commercially available worldwide. ENUM trials began since 2003 in different countries such as Australia, Austria, China, France, Germany, Korea, Netherlands, Sweden, Switzerland and the United States. Prior to the implementation of ENUM in the United States, the Department of Commerce (DoC) issued an endorsement regarding the participation of the U.S. of the official ENUM trial and to create guidelines particularly to protect the users privacy and security.

Internet Engineering Task Force

Request For Comments

International Telecommunication Union

Internet Architecture Board

Top-Level Domain

Internet Assigned Numbers Authority