Arbor's Labovitz was not so sanguine. "Enterprises that want to expand their data centers, expand their networks will begin to encounter shortages of IPv4 address space. Or it may be more expensive," Labovitz said.
A moment of truth for IPv6 will be June 8, when the Internet Society conducts a test in which Google, Yahoo, Facebook and other major Web entities turn on IPv6 on their home pages for a day. A large-scale test is needed to identify problems with running IPv6, said Leslie Daigle, chief Internet technology officer at the Internet Society. "I think there is a real possibility that a significant number of users will have to adjust their configurations" to access IPv6-enabled sites, Daigle said.
As long as they plan well, enterprises should be able to migrate without major challenges, but everyone should expect change over the next few years, Daigle said. "We can expect the landscape of the Internet to be a little turbulent over the coming while."