In addition, 23 per cent say they are not concerned about depletion of IPv4 addresses "in the near future."
Other reasons cited for putting off the migration to IPv6 are that it's too complex or too costly.
"Eventually the Internet registries are going to run out of IPv4 address space, and new companies are going to have to go to IPv6," Rooney predicts. "That will drive others to expose their networks at least externally to IPv6, which will drive further migrations."
On the plus side, IT professionals see value in many features of IPv6. More than 75 per cent of survey respondents said IPv6 features such as built-in security, better quality of service, expanded address space and routing enhancements were extremely or somewhat valuable.
But IT professionals say they need more evidence of the bottom-line business benefits associated with IPv6 in order to deploy it.
When asked what would help them convince upper management to deploy IPv6, 24 per cent said case studies showing a positive return on investment for IPv6, 22 per cent said case studies linking IPv6 solutions to business drivers, and 18 per cent said case studies showing how IPv6 helped a company achieve a competitive advantage.
In contrast, only 9 per cent of survey respondents said evidence that IPv4 address depletion was imminent would persuade upper management to upgrade to IPv6.
"You need a business reason to make this investment," Rooney says, adding that he believes the lack of IPv6-enabled applications is slowing down the migration to the new protocol. ``Having applications that take advantage of IPv6 applications for ad hoc networking, mobility, manufacturing, transportation and public safety will provide new business opportunities that would perhaps be a driver from an industry perspective."
In general, IT professionals are slightly less enthusiastic about IPv6 than they were two years ago. The number of IT professionals who believe IPv6 is mature enough to deploy dropped from 70 per cent in 2005 to 68 per cent in 2007. The number of IT professionals who said that IPv6 has value but doesn't link to business drivers rose from 58 per cent in 2005 to 69 per cent in 2007. And the number of IT professionals who said there is not a strong enough return on investment for IPv6 rose from 71 per cent in 2005 to 73 per cent in 2007.
Most telling, though, is the rise in the number of IT professionals who don't see any need to upgrade to IPv6. The number of survey respondents who said IPv6 does not provide benefits to their network infrastructures rose from 33 per cent in 2005 to 49 per cent in 2007.
"The larger service providers that we deal with are definitely moving to IPv6. The cable industry is going in that direction and the wireless carriers...But most enterprises have no concrete plans," Rooney says. "It's going to be a slow evolution."