When I'm not at the beach, the slower office environment of summer is a good time to catch up on industry trends.

Over the years, I've been most fascinated by the inexorable "have to happen" trends that never materialise -- Open Systems Interconnections is my favourite example. As I catch my breath in our summer break, I wonder if IPv6 might end up in the same category, at least as far as the enterprise is concerned.

At The Tolly Group, our business is evaluating IT across a wide range of product areas - switching, access routers, security, VOIP, wireless LAN, messaging and so forth.

As I look back on the last year of projects, there were many things in common as lines blurred among product types. But the one element consistently absent was IPv6.

Vendors come to us to get independent certification of their solution's capabilities. They are largely driven by what their prospective customers want to see proven. Can the absence of requests for inclusion of IPv6 in test scenarios reflect a lack of interest on the part of the enterprise customer? I think it does.

According to the IPv6 website, the world needs to replace the existing IPv4: "Most of today's Internet uses IPv4, which is now nearly 20 years old. IPv4 has been remarkably resilient in spite of its age, but it is beginning to have problems. Most importantly, there is a growing shortage of IPv4 addresses, which are needed by all new machines added to the Internet.

"IPv6 fixes a number of problems in IPv4, such as the limited number of available IPv4 addresses. It also adds many improvements to IPv4 in areas such as routing and network autoconfiguration. IPv6 is expected to gradually replace IPv4, with the two co-existing for a number of years during a transition period."

But these are problems network executives do not seem to notice. While the address shortage is real, the winning combination of network address translations (NAT) in firewalls combined with VPN technology has made most enterprises immune from that issue.

Using this technology combination, the enterprise can implement a private IPv4 address space without caring whether the address space is in use elsewhere (which it certainly is).

VPN tunnels, using IPSec/Point-to-Point Tunnelling Protocol or SSL, let remote offices, mobile users and business partners tunnel into the private corporate address space across existing IPv4 networks.

Fortunately, today's firewalls and VPN endpoints are sufficiently powerful so there is little or no noticeable performance penalty for either the NAT function or the encrypt/decrypt associated with the VPN tunnels.

In short, it works just fine. If you polled enterprise network managers and asked them the top 10 items that they want to change or upgrade in their network, I doubt IPv6 would make the list.

I'm sure that some reader is getting ready to write to me that IPv6 is much more important outside of North America and that it is being driven by various governments requiring IPv6 support in any new technology they buy.

I can't comment on the former, but for the latter I've seen at least one instance of what I call "prove, then remove."

I remember seeing one infrastructure vendor that implemented enough IPv6 to meet the checklist requirement. Then, apparently with the customer's approval, the IPv6 code was removed before deployment, which, naturally, was taking place on an IPv4 network.

For so many reasons, IPv6 is not on my near-term forecast for the enterprise.

Kevin Tolly is president of The Tolly Group, a strategic consulting and independent testing company in Boca Raton, Florida.

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