According to the Internet Society, thousands of companies and millions of websites are now permanently deploying IPv6. So it's safe to say the Internet is officially no longer a homogeneous IPv4-only Internet - it is a dual-protocol IPv4-IPv6 Internet. While the proportion of IPv6 Internet traffic is relatively small today, the composition of today's Internet is already shifting.

Beyond the broad participation in World IPv6 Launch Day last month, evidence of this shift can be found on the European Regional Internet Registry, RIPE NCC website. This page presents a chart illustrating the percentage of IPv6 networks as a percentage of total networks advertised on the Internet over time.

The percentage of IPv6 networks has surpassed 13 percent, up from 10 percent a year ago. From an absolute quantity perspective, over 5,500 IPv6 networks are now being advertised, up from 3,800 a year ago, a 46 percent increase. This means that a growing number of organisations have already deployed IPv6 to enable IPv6 Internet communications.

And the number of IPv6 users is expected to grow as the global demand for IP addresses increases unabated, driven by explosive rates of mobile and wireless subscriber growth, particularly in the eastern hemisphere where IPv4 address space is already depleted. And evolving "smart" initiatives like smart cars, smart homes, etc, featuring vast distribution of IP-addressable probes and devices for remote monitoring and control, promise to be massive consumers of IP addresses.

At BT, we've been conducting periodic surveys over the last seven years to gauge IPv6 interest and deployment. We concluded our most recent IPv6 survey in May and it's clear that more people are looking into IPv6 this year than in prior years. With a respondent tally of over 875, up about 50 per cent from last year's total, it's clear that interest in IPv6 continues to climb.

Key among our findings from the survey was that 13 per cent of respondents indicated that they had already deployed IPv6 across all or a portion of their networks. This is up from only five per cent last year, a substantial jump. Another 44 per cent are in the process of deploying IPv6 or will begin deployment within two years. And among those who indicated that they had not yet even considered IPv6 deployment, only 12 per cent of respondents fell into this category this year, down from 16 per cent last year.

The need for organisations to deploy IPv6 is primarily driven by the fact that IPv4 and IPv6 do not natively interoperate.

As the proportion of IPv6 users increases with continuing IP address demand, the best approach to enable communications with these users is to deploy IPv6 while maintaining your IPv4 implementation. Survey respondents agreed that such a "dual stack" approach was favored over tunneling and translation approaches. This entails assigning both an IPv4 address and an IPv6 address to each device on the network, say your web servers for example.

When assigning two addresses to your web server, you'll need to make sure your domain name server, DNS, is configured properly to direct your website "www address" to both the assigned IPv4 address and the IPv6 address. The dual stack approach enables end users of either protocol, IPv4 or IPv6, to reach your Internet servers, and to allow your users to communicate with other Internet servers (in accordance with your security policies of course!).

Should you decide not to deploy IPv6, your Internet presence will continue serving IPv4 users, which, as stated earlier, comprises a vast majority of Internet users today.

However, as the density of IPv6 users on the Internet grows, these users will be unable to reach your Internet sites. And your users will be unable to reach theirs. Certainly this is not an immediate threat to your ubiquitous Internet presence, but with shrinking IPv4 address capacity around the globe coupled with insatiable IP address demand, the population of IPv6 users will grow rapidly.

But if IPv6 deployment may not be an immediate project, why and when should you consider deployment? We recommend you begin planning now or in the near future even if you don't have immediate deployment plans.

The process of deployment may be relatively simple or very complex and time-consuming, depending on your deployment scope and current networking and computing environment. Planning for IPv6 deployment in advance can help identify steps to deployment and streamline the process in preparation for the time when deployment is deemed necessary.

As to when that time will come, our survey respondents were split across the board when asked at what IPv6 density threshold they'd begin deployment. Most answered that they have no set threshold and will decide based on industry trends or company needs. But the key is to do the planning now, so when that time comes, you'll have a plan in place to begin deployment smoothly.

Kevin Taylor is president, Asia Pacific, BT Global Services