NTT's Verio subsidiary last month became the first ISP in the U.S. to offer commercial-grade, nationwide service that supports IPv6, the next generation of the Internet's main protocol.Developed by the Internet Engineering Task Force, IPv6 promises easier administration, tighter security, greater mobility and an enhanced addressing scheme over IPv4, the Internet's current protocol.IPv6 uses a 128-bit addressing scheme and can support a virtually limitless number of uniquely identified systems on the Internet. In contrast, IPv4 supports only a few billion systems because it uses a 32-bit addressing scheme.ISPs in Europe and Asia already offer commercial IPv6 services because companies in those regions of the world have fewer IPv4 addresses than their U.S. counterparts.Verio has been offering an experimental IPv6 service at a few of its U.S. network POPs for a few years. Now Verio is offering native IPv6 connections, IPv6 tunnel connections and dual IPv4\/IPv6 services at every POP in the U.S. where it offers Internet access.Verio has several customers for its IPv6 services including the University of New Hampshire."Our targets are universities, other [research and development] institutions and companies looking to develop next-generation IPv6 applications," says Cody Christman, director of product engineering for Verio.Verio is also targeting the Department of Defense and military contractors with its IPv6 service. The Defense Department's CIO John Stenbit has set a goal of 2008 for the agency to migrate all of its communications to IPv6. Stenbit mandated that all IT purchases be IPv6 capable as of Oct. 1, 2003."We see a huge opportunity with the Department of Defense and government contractors," Christman says.\u00a0Verio's IPv6 services will be priced the same as its IPv4 services. "If you buy a fractional DS-3 in IPv4 or a fractional DS-3 in IPv6, the pricing is going to be about the same," Christman says. "The bandwidth charge is identical."Christman says Verio will not charge a premium for its IPv6 service because the cost to upgrade the company's network to support IPv6 was negligible. He also says Verio's enterprise customers are unwilling to pay extra for IPv6."We've been working with IPv6 since 1997," Christman explains. "We always kept it in mind when upgrading our switches and routers. So there was no capital expenditure to deploy this."The IETF finalized IPv6 in 1998, but until now ISPs were reluctant to offer it because their corporate customers weren't asking for it.IPv6 advocates hailed Verio's announcement as a sign that the new technology was finally gaining momentum in the U.S. market."Just recently more and more people have woken up to the fact that IPv6 is coming," says Ben Schultz, managing engineer for the University of New Hampshire's Interoperability Lab, which uses Verio's service.The university's Interoperability Lab serves as the network operations center for Moonv6, the largest network ever built using IPv6. Moonv6 connects more than 80 servers, switches and nodes located in eight states.Moonv6 was completed in October and is running both IPv6 and IPv4. So far, 26 network hardware and software vendors have tested their products for IPv6 compliance and interoperability on the Moonv6 backbone."Overall, IPv6 works," Schultz says. "The base specification has been tested for a very long time and it's mostly stable. We still need to do more testing in security and mobility."