IPv6 has long suffered from the perception that it is a good solution looking for a problem to solve. The Social Security Administration's hands-on experience with this upgrade to the Internet's main protocol does little to change that perception.

In the last two issues of the Service Provider News Report, I've looked at SSA's preparations to support IPv6 on its production network by June 2008. I've also offered tips from SSA officials about getting ready for IPv6. (See parts one and two of this series.)

What I found striking about SSA's five-year experience with IPv6 is that the agency has yet to find one concrete benefit of the technology.

"We use all the add-ons for IPv4 that are also in IPv6. Right now, we don't know of any benefits of IPv6'' that will help SSA in its mission, says Rich Terzigni, senior network advisor in SSA's Office of Telecommunications and Systems Operations. "Once IPv6 applications become available, it's possible that we can do agency business in less time or more efficiently because of IPv6."

IPv6 was created a decade ago to solve a forecasted shortage in IPv4 address space. IPv6 uses 128-bit addresses that can support a virtually unlimited number of computers and devices connected directly to the Internet. IPv4, on the other hand, uses 32-bit addresses and can support approximately 4 billion systems.

In the United States, many corporations and government agencies like SSA have enough IPv4 address space or use techniques such as network address translation and proxies to stretch their limited number of IPv4 addresses to support many users. For these folks, IPv6 offers ancillary features including built-in security via IPSec, auto-configuration of devices and enhanced mobility.

I asked SSA officials about the main enhancements that IPv6 has to offer, and here is what they said:

What about address space?

SSA has what's called a Class A block of IPv4 addresses, and so far the agency doesn't need any more.

"Right now we manage our resources very well, so right now we don't need extra addresses," Terzigni says. "Who knows if we will in the future? SSA sites haven't been increasing, and neither have our number of employees. But if the desktop requires multiple addresses, that is going to dictate IPv6 right there. If we need more than one IP address per user, we're dead."