For telecom service providers, the transition from IP Version 4 (IPv4) to IPv6 has been a long time in coming -- many have been planning for the change for more than a decade, and most have been IPv6-ready in the core of their networks for a couple of years now, offering IPv6 services to those interested.

But for enterprises, the picture has been very different. The primary driver to IPv6 -- the diminishing pool of IPv4 network addresses -- has been largely offset by the proliferation of Network Address Translation (NAT) technology that has enabled multiple endpoints to share IP addresses. Since most business applications don't use IPv6, the transition to this new Internet addressing scheme has often seemed to lose any sense of urgency.

This may be the year that all changes. Major service providers are seeing an uptick in IPv6 interest, and are re-marshaling their efforts to help enterprise customers in what is often a tricky transition, given the extent to which IPv4 addresses are embedded in networks and applications.

"If you look at the NANOG [North American Network Operators' Group] community events, two years ago, we would have four or five talks on IPv6, and the comment would be 'Not another talk on IPv6,' " says Jason Schiller, senior Internet network engineer for Verizon Enterprise Solutions . "Now people can't get enough talk about IPv6. At least in the operator community, the interest and consciousness for v6 has certainly awakened."

Some of this new interest is based on the reality that the Internet Assigned Numbers Authority will run out of IPv4 addresses in September of 2011, based on current projections. There is also the looming prospect of 4G wireless rollouts, which could send many more address-hungry wireless devices into the field and trigger a more rapid rollout of IPv6 than has happened to date -- something many say is already happening in Asian markets.

The US federal government already did its bit to accelerate IPv6 -- when the General Services Administration issued the Networx contract in 2007, it required anyone seeking federal agency business to be IPv6-compliant. And there are more business applications, from Microsoft Corp. (Nasdaq: MSFT) and others, that use IPv6.

The Alliance for Telecommunications Industry Solutions (ATIS) has had a task force that worked on IPv6 transition issues, and actually developed an ATIS Readiness Plan for service providers to use in aiding their customers in the transition, issued in 2007 and 2008.

ATIS has seen a decided uptick in interest for those documents of late, says CEO Susan Miller.

AT&T Inc. (NYSE: T) has seen greater interest from its customers in at least talking about the IPv6 transition within the last year, "because they want to get their heads on straight," said Dale McHenry, AT&T's vice president of enterprise services.

There is still no guarantee of a smooth transition, however, as many enterprises look at any investment in IPv6 technology as an unnecessary expense at a time when their budgets have never been tighter.

"The mass adoption is still in a wait-and-see mode," said Bob Schroeder, director of business development for Qwest Communications International Inc. (NYSE: Q) Business Markets Group. "They are challenged to prioritize this kind of investment over other things in their budget."

A long time coming
Verizon Business, in its MCI mode, has been planning for IPv6 since 1998, and had Metropolitan Area Exchanges engaged in IPv6 peering as far back as 2002, said Schiller. By 2006, the technology was rolled into its Internet backbone.

But while Verizon has a number of customers who have embraced IPv6, most of them "are in the testing and getting acquainted [phase] with v6 at this point," Schiller said. "The vast majority are looking at a tick box on an RFP, making sure their vendors will be able to support IPv6 when they need it, and be able to help them make the transition."

That's the minimum level of commitment that Verizon is recommending, Schiller said -- to have an IPv6 plan in place today.

"The most important thing to do is to understand that IPv6 is coming and to be prepared for it," he said. “If your equipment is not IPv6-capable today, at least make a minimum investment to get some v6-capable equipment, come up with an addressing plan, your architecture, your design, and test it to make sure it is going to meet your specifications. Then roll it out on a minimum of equipment."

Service providers, including AT&T, Global Crossing (Nasdaq: GLBC) Qwest, and Verizon, are offering enterprise customers a range of services to aid in the transition, beginning with assessments and progressing through deployment.

"When a customer tells our account team they are interested in IPv6, we come in and we advise -- we have an IP SWAT team of technical folks that come in and do things like auto-discover addresses in their network and put maps together that detail how they would migrate from v4 to v6," said Qwest's Schroeder. "Then, when they are ready to make the transition, we offer project management."

AT&T also does assessments, and those tend to reveal how tricky the transition to IPv6 can be, and how necessary it is to plan ahead, says McHenry.

"I think folks are starting to understand as they dabble in this that it is much bigger than just a network thing," he said. "The network is key, but there are a lot of things that connect to the network -- routers, servers, all the software in the servers -- that [are] involved as well. There is a lot of corporate IT software that has a lot of IPv4 addresses in them, with commands that are unique to v4. There is a lot of embedded code as well."

The real value of the service provider assessment is the ability to reveal those complexities and spell out how to address them, McHenry says.

Service providers as IP drivers?
Most service providers are saying they hesitate to push IPv6 on their enterprises customers, however, saying they can promote awareness but not drive adoption.

"I think it's a double-edged sword," says Mark Bath, senior director of applications services for Global Crossing, which today has about 40 Internet customers operating on v6 and about 20 peering partners as well. "If you don't prepare yourself, and if that killer app comes along on IPv6, then you are going to lose out. But are service providers going to generate those killer apps?"

Until enterprises see their applications requiring IPv6 support, they are loathe to spend valuable capex, Bath says.

Verizon's Schiller says his company is pushing it "a little bit" with its enterprise customers, but even so, he admits, there is only so much that can be done, absent economic drivers for change.

"If there is legacy equipment that has to be replaced, and there is no new revenue that is going to be generated, there is a big cost there," Schiller says.

As a result, agrees AT&T's McHenry, the business case winds up being a negative one: By moving to IPv6 now, or at least planning the move and starting the transition, enterprises can avoid the later pain -- and greater expense -- of scrambling to react to IPv6 and applications that require that technology.

In the meantime, service providers are also upgrading their own networks to handle the transition, including what may be a long period of time when IPv4 and IPv6 have to coexist in the network. The next article in this series will examine that challenge.

— Carol Wilson, Chief Editor, Events, Light Reading