Enum and VOIP Technology

Enum stands for E.164 NUmber Mapping. Telephone number mapping is the process of merging the public switched telephone network's (PSTN) telephone number system with Internet telephony (VOIP). Telephone numbers are organized under the E.164 standard, whereas the Internet employs the domain name system for linking domain names to IP addresses. Enum uses special DNS record types for translating a telephone number into a uniform resource identifier or IP address that can be used to communicate on the Internet. Most people understand or are at least able to use the traditional number system without a problem, but those who aren't familiar with VOIP can learn more about it here at enum-forum.org.

Voice over internet protocol, or VOIP, is part of a group of communication and transmission technologies used to deliver of voice communications and multimedia sessions over the Internet. Other terms commonly related to VOIP and even used in its stead are IP telephony, Internet telephony, voice over broadband, broadband telephony, and broadband phone. VOIP has several benefits, such as a low operational cost and the flexibility to transmit more than one telephone call over a single broadband connection, secure calls using standardized protocols, integrating with other services available over the Internet, and more.

In order to use ENUM, a person needs to have a personal uniform resource identifier (URI), an E.164 regular personal telephone number associated with the personal URI, and authority to write their call forwarding/termination preferences in the NAPTR record accessible via the personal URI. The parties involved with Enum include the subscriber, who makes their access information available to others; the registrar; which manages the subscriber’s access information and makes sure that it is publicly available on the Internet; the registry, or manager of a national Enum zone; the regulator, normally a governmental body with control over the National zone of Enum; and the number holder operator.

There are also different types of Enum, mainly public, the original vision of a global, public directory database; private, in which a carrier, VOIP operator or ISP may use ENUM techniques within its own networks; and carrier, where groups of communication service providers agree to share subscriber information via ENUM in private peering relationships. These same carriers control subscriber information, not the individuals. This is also referred to as infrastructure ENUM, and is being the subject of new IETF recommendations to support VOIP peering.

Currently, when a user places a regular phone call, he has to start by deciding how to establish the call with the other party, via VOIP, PSTN, cellphone, entering a URI or dialing a number. With Enum's telephone number mapping indirect dialling it is the called party who solves that question. Another advantage of indirect dialing is to allow the user to change their phone telco, webpage, IMS, email or whatever service they use without having to tell all his contacts about that.