IP address management company Nominum followed up a record-setting ENUM benchmark announcement earlier this month at the VON Conference with a $16 million funding round this week led by Advanced Technology Ventures.

The total equity investment in Nominum now stands at $45 million thanks to ATV and other investors, including: Bessemer Venture Partners, Morgenthaler Ventures, Globespan Capital Partners, Presidio Venture Partners and Silicon Valley Bank. Nominum will use this investment to continue expansion of its worldwide sales and business operations.

Nominum was founded in 1999 by chief technology officer David Conrad to develop BIND9 and ISC DHCP3 for the Internet Software Consortium (ISC.) In 2000, Nominum offered a domain name system (DNS) hosting service called Global Name Service, which hosted thousands of enterprise customers as well as several top-level domains. It was based on the DNS technology that Paul Mockapetris, chairman and chief scientist, invented in the 1980s at the University of Southern California's Information Sciences Institute.

In 2002, Nominum sold its managed service business to concentrate fully on developing and supporting next-generation solutions. Its customers include British Telecom, Samsung Networks, ASAHI Net, COLT Telecoms, NTL, Telewest, 3 and KPN.

One of those next-generation solutions is called ENUM, which is not an acronym, but a technology used to map traditional telephone numbers to Internet-friendly domains that can be stored in DNS servers. It addresses routing issues between PSTN and voice-over-IP networks as well as between VoIP-based networks.

"ENUM will push DNS like its never been pushed before," said Albert Gouyet, vice president of marketing at Nominum.

ENUM can be deployed in either of three ways: publicly, where a DNS server gets populated with ENUM information and is available to the Internet; internally to a private carrier network; or open to certain carrier peering partners. Gouyet expects to see the first large-scale private deployment within the year.

Earlier this month, Nominum released benchmark results for ENUM performance in its Foundation Authoritative Name Server (ANS) that scaled to 45,000 queries-per-second against 200 million customer records running on commodity hardware. With an average latency of two milliseconds, the ANS raised the bar by as much as four times other software.

Nominum also announced the availability of open source extensions to the "queryperf" program, a DNS server performance measurement tool capable of simulating DNS clients' requests. The extensions increase the performance of queryperf to allow service providers to compare the performance of Nominum's products over the open source-based alternatives.

According to a report from the consultancy Ovum, 24 countries have received ENUM delegation of their country codes and 10 countries have started public ENUM trials.

"The last five or six months we couldn't find people with checkbooks. They showed interest, but were thinking on a philosophical level," said Chris Risley, president and CEO of Nominum. "But two things changed: The economics of VoIP are more compelling and carriers are starting to think about peering with their brethren. ENUM is a standardized answer for that."