Carriers and users prepare to midwife ENUM

The long-awaited debut of ENUM - the mapping of globally recognized telephone numbers to the Domain Name System - is beginning in earnest, although the technology is still not quite ready for widespread deployment. Promoted as a way to enable end-to-end voice-over-IP (VoIP) connectivity and various other IP-enabled applications, ENUM was long expected to be controlled by end users. However, recent industry activity and standards-body discussions have turned the notion of end-user ENUM on its head, instead favoring carrier ENUM or infrastructure ENUM - that is, VoIP service providers will exchange information among themselves about ENUM-enabled numbers, thus avoiding fees collected by public switched telephone network (PSTN) companies for bridging calls between VoIP providers.