As advanced IP applications make their way onto corporate networks, researchers and service providers hope to see a corresponding move to IPv6, the long-suffering replacement to IPv4.

Yet pilot projects aimed at proving IPv6's mettle haven't shown how the protocol can propel businesses to a paradise full of advanced IP applications. Application work has been secondary to infrastructure tests.

At the Moonv6 test bed, for example, researchers have conducted detailed tests of the IPv6 routing protocol and the Point-to-Point Protocol over Ethernet but have not yet tackled advanced applications, says Ben Schultz, managing engineer at the University of New Hampshire Interoperability Lab. UNH administers the Moonv6 test bed, which is a collaboration among the Internet2 university consortium, the North American IPv6 Task Force and the US Department of Defense. IPv6, developed by the IETF, touts IPSec and simple administration for tight security and, with its 128-bit address space, supports an almost unlimited amount of uniquely identified systems on the Internet.

While Schultz acknowledges a lack of advanced application development geared toward IPv6 today, he says he's looking forward to testing real-time collaboration tools and other applications to show how IPv6 will perform. Application work at the Moonv6 test bed to date has centred on running streaming media unicast and multicast applications across the network, he says.

Lessons learned and deployment tips from advanced application testing might help turn the tide for IPv6 adoption in business, where the protocol is still seen as a down-the-road technology.

"We've done some research on IPv6," says Vijay Sankaran, manager of enterprise technology for Ford Motor's IT group. "But it's still undetermined where the protocol will play."

IPv6 is "more efficient for the routing of messages and being able to know who your endpoint address is," says Sankaran, a member of the IPv6 Business Council. But, he adds, "everything we do for our business needs a core driver. And one thing we've been struggling with is that while this packet header can have additional information on it, we haven't found the applications that would have us invest money to go to an IPv6 network."

With limited resources, Ford would rather focus on rolling out a comprehensive wireless fabric around the campus, he says. That has a much higher value potential in the short term than IPv6, he adds.

IPv6's unlimited addressing would have worked well for Saugus Union School District as it rolled out VoIP, says Jim Klein, the organisation's director of information services and technology. Network Address Translation (NAT), used to assign IP addresses to the VoIP phones, gets tricky when calling outside the organisation, he says. With IPv6, each IP phone would have a unique address that would expand the capabilities of the VoIP system. Yet rather than working with IPv6, Klein created a suitable workaround for the problem.

Ultimately, such a workaround won't be an option. True advanced IP networks require IPv6, Klein says.

Phil Edholm, CTO and vice president of network architecture for Nortel's enterprise division, says: "Some applications, like voice over IP, just don't have the ability to do port mapping, so having individual IP addresses is important." Real-time collaboration, such as presence-aware instant messaging for employees, will require IPv6. "What's going to drive IPv6 is the need for constant connections. You can't have NAT in the middle."

Minus compelling evidence on application performance, that leaves IPv6 as a natural progression for many IT executives - a technology they get as they replace core gear with IPv6-enabled products. Already, major vendors, such as Cisco and Juniper Networks, are prepping and releasing IPv6-ready switches and routers, while Microsoft promises IPv6 support in its newest operating system.

But management, applications, middleware and security infrastructure required for most production networks are still missing, reports the IPv6 Forum.

Still, IPv6 advocates won't be derailed from their "deploy IPv6 now" mantra. IPv6 is critical to reaching an advanced IP paradise because of the billions of devices that will be deployed, they say. "The real issue is how many things can you put on the 'Net and distinctly address. Scaling puts a great challenge on the address space," says Vint Cerf, senior vice president of technology strategy at MCI. "Rather than waiting and having a crisis, let's move to IPv6 now."