Some doubt also exists as to whether the government's IPv6 mandate is having an impact on enterprise adoption in the United States for IPv6.

The move to IPv6 is of critical importance as the IPv4 address space near depletion and the U.S. lags behind the rest of the world in terms of adoption.

"We haven't really seen any last-minute rush," Tim LeMaster, director of systems engineering for Juniper Networks (NASDAQ: JNPR), told InternetNews.com. "Most agencies seemed to have used their time wisely since the OMB mandate was announced and now have a good handle on where they are relative to IPv6 compliance," LeMaster added. "This is not necessarily to suggest that they are all compliant, but most seem to know where their deficiencies lie if they have any."

The U.S. government announced the IPv6 mandate back in 2005. The mandate has served to be a wake-up call for the need for IPv6 in the government.

"I believe the mandate has raised the bar and awareness around IPv6," LeMaster said.

"Even if not all agencies and systems are v6-compliant by the deadline, we are much further along than we would have been without the requirement."

For Cisco's Doug Gourlay, senior director, marketing and product management, Cisco Data Center Business Unit, the mandate has created a compelling event to help drive adoption.

Gourlay noted that the U.S. government is a billion dollar plus customer for Cisco.

That said, he added that Cisco has been ready for years.

"IPv6 to me is relatively simple," Gourlay told InternetNews.com. "Six or seven years ago we started to make sure that all of the hardware products we were bringing to market were capable of supporting it," he said. "So while the mandate hits now, it's a good affirmation of the strategy we were already on."

The shift to IPv6 for the government has undoubtedly involved billions of dollars. Precisely how many billions has not yet been tallied. In 2005 a report forecast that the cost could hit $75 billion.

Outside of the government, Juniper is seeing a lot of interest in IPv6 within the wireless operators.

"Most of them seem to be really interested in IPv6 for their next-generation mobile networks," LeMaster said.

"We also see growing interest in IPv6 within the U.S. service providers, mainly around preparedness for the U.S. government mandate," he said.

"And of course the Asian and European markets are still very actively deploying IPv6 within their networks."

Next page: What about U.S. enterprises?