"The customers who do come and ask us about IPv6 tend to be the ones using our mobile monetization suite of services. These are the people concerned with iPads and devices," Tal says. "They want to know what new functionality they can enable because of IPv6. So mobile is driving IPv6 to some degree."

Some U.S. carriers are deploying IPv6 even if they aren't seeing much customer demand for it yet. , a Rochester, N.Y., provider of fiber-optic transport services, has rolled out IPv6 across its entire network using a dual-stack service, where IPv4 and IPv6 run side-by-side. Currently, less than 1% of Fibertech's traffic runs over IPv6. Customers that are interested in IPv6 tend to be educational institutions such as the University of Pittsburgh.

"Less than 5% of our new and existing customers are asking us for IPv6," says Tom Perrone, director of engineering and planning at Fibertech. "It's slow. We're doing everything we can to help customers set it up. We're sitting here patiently waiting for the IPv6 traffic to come."

One IPv6 proponent that's betting the IPv6 traffic will come soon is Google. At an Internet Society event in Vancouver in July, Google network engineer noted that IPv6 adoption grew by 150% in the last year. "At this rate, 50% of Internet users will have IPv6 in about six years," he said.

Among the statistics that Colitti highlighted were the fact that carriers such as AT&T had enabled 1 million of its DSL subscribers with IPv6 and planned to enable another 4 million by year's end. He said that AT&T's IPv6-enabled customers see 20% of their traffic transition from IPv4 to IPv6.