Dial 'ENUM' for murder?

Once, there was just a switched handset, firmly attached to wall, and the dial had letters as well as numbers--not to send email, but to select the local connection. Now, things are more complicated. Not only are there fixed and mobile phones, there is the internet--and the PSTN numbers of yore and IP addresses do not mix. That, however, is about to change, with industry blood-letting potentially to follow.

ENUM (Electronic Number Mapping) promises to overcome the PSTN/internet divide. ENUM is still based on the standard E.164 phone number system, but what it does it to flip the numbers round to use them as IP addresses--so mapping a PSTN number to internet services. (The number is, literally, reversed, a period is placed between the digits, '.el 64.arpa' is added at the end, et voila, a URL.) "ENUM is not a glamorous technology, but it is a very useful piece of glue, an application that will make life much easier," argues Julian Rose of Atlas Advanced Internet Solutions, which is trialling ENUM and is part of Timico, a provider of business telecom services, including converged voice and data.

ENUM is not a radically new idea. However, its circumstances have recently undergone a sea change. "The big thing that's different today is that the people with the chequebooks are talking about it," says Albert Gouyet, of Nominum, a provider of IP name and address management software. (Nominum's interest in ENUM is partly driven by the issue of making the DNS infrastructure robust enough to deal with the volume of queries that full ENUM implementation could drive.) Mechanisms for setting up a public ENUM database are in motion in many countries. The UK, for example, having carried out a consultation last year, is expected to make an announcement on its plans following the up-coming election. In Germany, a public ENUM database will be available from October.

This development could be both an opportunity and a threat. ENUM promises to pave the way for painlessly avoiding the PSTN. Users with a WiFi and SIP-enabled mobile could, for example, use ENUM to call up email addresses and URLs and then opt for a data connection, rather than an expensive switched voice call. "Many of the newer smart phones have Wireless LAN functionality," says Rose, "So it is not too big a leap to see how these devices could use VolP technology not only to make calls outbound over Wi-Fi networks, but also update ENUM records such that when they are in range of a Wi-Fi network they would publish their reach-ability for incoming calls (or SMS/ MMS) over VolP." Some handset manufacturers are already working on these features, Rose adds.

Speakers at a recent seminar on ENUM in London refused to be drawn on whether mobile operators were keen on the technology--one suspects that it is of more immediate interest to providers of fixed-line VolP. However, those present did appear to anticipate the disappearance of the switched/IP divide. "The telecom industry will move toward an 'all you can eat' model," argues Paul Mockapetris, chairman and chief scientist at Nominum and the inventor of the domain name system. Mockapetris also anticipates that ENUM will creatively destruct itself. "Phone numbers are here because there is a very large legacy base. I don't think we will be using them in thirty years. People will think about other ways to do ID," he says.

Identity is core to the appeal of ENUM, and also a core threat. "People want to call an individual, not an number," as Rob Barmforth of Quocirca, points out. However, if, for example, the wrong ENUM data were connected to a phone number, it would be possible to over-ride the forwarding wishes of the person whose data ought to present. Security questions are not the only pain point. Regulation is also likely to be thorny. "There will be issues such as deciding what VoIP is, who the dominant carrier is and who will carry USO obligations," points out Peter Aknai, an analyst with Analysys. Aknai also sees "a major strain on the naming and numbering systems." ENUM is not, however, dependent on the introduction of IPv6.

COPYRIGHT 2005 Horizon House Publications, Inc.
COPYRIGHT 2006 Gale Group