Who's afraid of IPv4 address depletion? Not IT professionals, according to a new survey due this week by BT INS, a Californian consulting firm.

Only 16 per cent of IT professionals consider IPv4 address depletion "a huge concern that has or will soon force us to migrate to IPv6," according to a BT INS survey of 310 IT professionals that was conducted in December 2007.

A whopping 26 per cent of IT professionals felt IPv4 address depletion was "no concern." These survey respondents said they can use network address translation combined with VPNs to alleviate the problem.

The majority of respondents -- 58 per cent -- said they had some concern about IPv4 address depletion but ``not enough by itself to cause us to migrate to IPv6 in the near term."

The survey results confirm what BT INS officials said they are seeing in the market: faint interest among IT professionals in IPv6 and weak demand for IPv6 products.

"IT professionals see no compelling benefit to IPv6," says Rick Blum, director of strategic marketing with BT INS. "IPv6 has a number of advantages including security and autoconfiguration, but none of these is compelling enough at this point for people to move. IPv4 address depletion would be the primary reason, but in North America we have much better availability of IPv4 addresses so that wouldn't be true."

IPv6 is a long-anticipated upgrade to the Internet's main communications protocol, IPv4. IPv4 uses 32-bit addresses and can support around 4 billion IP addresses. IPv6 uses a 128-bit addressing scheme and can support so many billions of IP addresses that the number is too big for anyone but a mathematician to understand. (IPv6 supports 2 to the 128th power of IP addresses.)

The Internet Engineering Task Force designed IPv6 in the mid-1990s to expand the available IP address space. The standards body added features such as built-in security through IPSec and easier network management through autoconfiguration to encourage network managers to upgrade their networks to IPv6.

During 2007, the threat of IPv4 address depletion came back to the forefront as the main reason for upgrading to IPv6. With 6 billion people on the planet and 1.3 billion already online, experts say that IPv4 addresses will run out soon.

The American Registry for Internet Numbers (ARIN) warned in May 2007 that IPv4 address depletion was looming, and the group said it would actively encourage migration to IPv6.

RIPE, the European Internet registry, followed in October with its own warning that IPv4 addresses would run out by 2011.