What do you need to know abut the switch to Internet Protocol version 6 (IPv6)? Axel Pawlik, managing director of RIPE NCC, takes a look at one of today’s most pressing issues.

At some point, probably before the end of 2011, the Internet Assigned Numbers Authority (IANA), the body responsible for the top-level distribution of IP addresses, will hand out the last unallocated IPv4 addresses.

The impact this will have on the internet industry and internet users is still under debate. It is clear that IPv6, the new generation of IP addresses, is vital to the continued growth and development of the internet. Ensuring that IPv6 is efficiently and effectively deployed is the major challenge facing the internet today.

Almost 90 per cent of the 256 IPv4 address blocks of ‘/8’ (‘/8’, or ‘slash eight’, corresponds to 16,777,216 unique IPv4 addresses) have already been allocated, and of the remaining blocks, 35 are reserved for the Internet Engineering Taskforce (IETF). The outstanding addresses are held by the IANA for future allocation to the Regional Internet Registries (RIRs). The RIRs, in turn, distribute addresses to ISPs and other users in their respective regions.

Why now?

The internet has undergone extraordinary growth over the past decade. Commitments in the recently published Digital Britain report and the latest internet usage figures highlight just how significant the internet has become as part of modern daily life.

The number of UK households with internet access increased by 1.2m in the last 12 months alone, and with two thirds of homes now connected, over 70 per cent of us use the internet on a daily basis. This number will only continue to rise. One of the primary aims of the Internet Governance Forum (IGF), set up by the UN, is to get the next billion users online. Every device that is used to connect to the internet will require an IP address.

As the reach and scale of the internet continue to grow, we keep finding new ways to use it. Global communications have evolved, transforming the way we work and play. More and more consumers and businesses want to be able to use the internet, whilst on the move.

The business case is already clear – high-speed mobile internet access allows employees to a use a variety of applications on the move, increasing productivity and streamlining decision making processes. In today’s economic environment these attributes represent a crucial competitive advantage for any organisation.

What’s next?

In order to connect all of these people and devices to the internet more IP addresses are needed. With this in mind, the technical community developed Internet Protocol version six (IPv6) in the mid-90s to meet future demand. IPv6 is an internet protocol developed as an alternative to IPv4. Rather than using a 32-bit system, IPv6 is based on 128-bit addresses, meaning that there are 2128 individual addresses available, which is approximately 3.4×1038, and exactly:


IPv6 provides enough addresses to allow the internet to continue to expand and the industry to innovate. It is not however, directly compatible with IPv4, meaning that a device connected via IPv4 cannot communicate directly with a device connected using IPv6.

The original plan was that as the internet grew and the IPv4 address pool was depleted, IPv6 would be deployed. According to this plan, the deployment of IPv6 would be complete long before the last IPv4 address was allocated.

This has not happened, and IPv6 deployment activity to date has been minimal. This is now a real problem, because the transition to IPv6 will now have to take place beyond the exhaustion of the IPv4 address pool. Therefore, as the internet continues to grow, network operators will have to dual stack - or run both IPv4 and IPv6 simultaneously.

The RIRs are working hard to ensure that IP addresses are allocated responsibly, and only when needed, but even so approximately 268 million unique addresses are allocated every year. If there are no IPv4 addresses for new users, how will new networks be able to implement dual stack? And how will they talk to the rest of the internet?

Essentially, we have less than two years before the industry has to face up to these questions. Dual stack, as currently envisioned, works fine until around 2011, but beyond that, the IPv4 part of new, dual stack networks may cause problems.

How to deploy and why not to delay

It is vital that your organisation is compatible with both IPv4 and IPv6. If you choose to stick with IPv4, you won’t be able to connect new devices directly to the internet, only via a NAT (Network Address Translation, a technology that allows many devices to use the same address). Similarly users on IPv6 won’t be able to access your website and services, and are likely to turn to your competitors.

When business leaders make firm decisions to deploy IPv6, the process is fairly straightforward. Staff must be trained, management tools need to be enhanced, routers and operating systems need to be updated, and IPv6-enabled versions of applications need to be deployed. All of these steps, however, will take time and money.

Some businesses have been put off by the perceived cost of implementing IPv6. But, in fact, the longer you wait to adopt IPv6, the more expensive it will be, as last-minute deployment and poor planning are likely to increase costs. Businesses should therefore develop a comprehensive deployment plan now.

Key steps to migration include:

  • Carry out a hardware and software audit to determine the compatibility of existing technologies with IPv6;
  • Upgrade equipment;
  • Train staff;
  • Rewrite any of your own applications that store IP addresses to be IPv6 compatible;
  • Organise IPv6 connectivity and address space;
  • Ensure that your current ISP supports IPv6.

Only once all of these elements are in place, can IPv6 be implemented effectively.

The RIRs have well-established, open and widely supported mechanisms for internet resource management and we are confident that our Policy Development Process meets and will continue to meet the needs of all internet stakeholders through the period of IPv4 exhaustion and IPv6 deployment.

The immediate challenge lies in encouraging all organisations in both the public and private sectors to make content available via IPv6, to ensure the continued growth of the internet.

For further information on IPv4 depletion and adopting IPv6, please visit www.IPv6ActNow.org.