2 November 2009

IPv6 What is it, why is it important, and who is in charge?

IPv6 What is it, why is it important, and who is in charge?
… answers to common questions from policy makers, executives and other non-technical readers.

A factual paper prepared for and endorsed by the Chief Executive Officers of ICANN and all the Regional Internet Registries: October 2009

1. What is IPv6?

“IP” is the Internet Protocol, the set of digital communication codes which underlies the Internet infrastructure. IP allows the flow of packets of data between any pair of points on the network, providing the basic service upon which the entire Internet is built. Without IP, the Internet as we know it would not exist.

Currently the Internet makes use of IP version 4, or IPv4, which is now reaching the limits of its capacity to address additional devices. IPv6 is the “next generation” of IP, which provides a vastly expanded address space. Using IPv6, the Internet will be able to grow to millions of times its current size, in terms of the numbers of people, devices and objects connected to it[1].

2. Just how big is IPv6?

To answer this question, we must compare the IPv6 address architecture with that of IPv4. The IPv4 address has 32 bits, allowing today’s Internet to connect up to around four billion devices. By contrast, IPv6 has an address of 128 bits. Because each additional bit doubles the size of the address space, an extra 96 bits increases the theoretical size of the address space by many trillions of times.

IPv6 address space is huge (try comparing a golf ball (IPv4) to several times the planet (IPv6), It is certainly not infinite, but it is not going to run out any time soon. Each of the RIR’s has already been allocated at least one block of IPv6 addresses which is of itself bigger than the entire current IPv4 space. When subdividing and distributing addresses, generous allocations are preferable, as they provide greater flexibility and efficiency in network design, benefiting service providers and end-users alike. However, these will also result in wastage of addresses, so a suitable balance must be maintained between a simple administrative framework and the need for ongoing conservation of addresses.

In developed countries today, the rate of utilization of IPv4 addresses is generally around 2 addresses per head of population[2]. If this rate of Internet penetration were replicated throughout the world, a total of 12 billion addresses would be needed, an impossible achievement since IPv4 provides a maximum of just 4 billion addresses. On the other hand, the same level of IPv6 penetration would require less than one billionth of the entire IPv6 address space[3].

IPv6 provides an address space which is sufficient to provide addresses for any conceivable number of individuals, organizations, devices, or network-enabled objects in the foreseeable future (for a number of centuries, at least). Even assuming a uniform global Internet which is a million times denser than that of today’s most advanced economy, IPv6, if properly managed, will be able to provide the required addresses[4].

3. How are allocations made, and to whom?

IP addresses are managed under a system which has been in operation for some 15 years, and which has supported the successful growth of the Internet by a factor of over 100 in that time[5]. This system was established initially by the Internet Engineering Task Force (IETF)[6], a recognized international standards development organization which is the home of the Internet’s core technical standards.

Today, organisations known as Regional Internet address Registries (RIRs[7]) receive IP addresses from a central global source, the IANA (or Internet Assigned Numbers Authority, which is operated by ICANN, the Internet Corporation for Assigned Names and Numbers[8]). The RIRs then make allocations directly to Internet Service Providers (ISPs) within their respective regions. This system achieves a balance between the uniform resource management (which is critical to the maintenance of a single globally cohesive Internet), and the direct service of the needs of ISPs (namely, those who need and use Internet address space).

Each of the RIRs is a non-profit organization, and acts in accordance with policies and practices which are established by the Internet community in its region[9]. These policies and practices govern the management, allocation, usage and recovery of IP address space (both IPv4 and IPv6) according to the best current practices of the Internet, its industry and stakeholders. At the global level, policies and practices are coordinated through the Address Supporting Organisation (ASO[10]) of ICANN.

In some cases (currently 8 in total), National Internet address Registries (NIRs) provide services within a specific country or economy, in effect as an agent of the RIR[11]. Such registries operate under the policies and authority of their RIR, and do not receive their own allocations of IP address space[12]. The existence and operation of NIRs is specific to local needs and circumstances: for instance, some may be Governmental bodies while others may be independent.

4. How are IPv6 addresses actually being allocated?

Like IPv4, IPv6 address space is allocated by the RIR’s in line with the topology of the network itself, to the Internet Service Providers (ISPs, and similar organizations) who require it. Allocations are made under a set of transparent address management policies, in accordance with the demonstrated technical needs of the recipients. When new technologies or applications are developed which may impact upon address management techniques, these are accommodated via an open policy development process which allows policies to adapt accordingly.

In their policy-making to date the RIR communities have made a series of specific decisions to ensure that there are minimal barriers to IPv6 adoption by ISPs and others. At present the minimum size of an IPv6 allocation to any ISP is greater than the entire existing global IPv4 address space, yet each allocation is the equivalent of only a single IPv4 address on today’s Internet (one four-billionth of the available address space).

At the end user level, IPv6 addresses are also allocated in very substantial blocks rather than in single addresses or small blocks, as has been the case with IPv4. Under today’s policies, each IPv6 user receives enough address space to allow the use of hundreds or thousands of separate segments within a home or business network. Depending on their service configuration, each end user has enough address space to address any conceivable number of devices (literally millions) which might be used. This will allow IPv6-enabled devices including appliances, sensors and objects to be deployed easily and cheaply in the large numbers which are expected in coming years.

5. Why did such large IPv4 address allocations go to US organizations, including the US Government, and its Department of Defense?

The Internet was developed by the US Defense Advanced Projects Research Agency (DARPA), and was originally used by the American Government and academic organisations. Until the late 1980s the Internet was never expected to become a critical global infrastructure, and IPv4 address allocations were made in a liberal manner, not just in the US, but to government and academic institutions throughout the world. This resulted in many large allocations of IPv4 address space, and the early depletion of the IPv4 address pool (to the extent that in 1991, more IPv4 addresses were allocated than in any year since then[13]).

It was only in the early 1990s, when an Internet “boom” became apparent, that concerns arose about the rate and manner of address space distribution[14]. At this time, the RIR system was proposed[15] in order to ensure that addresses were managed by the Internet community itself, in the best possible manner. At the same time, work was started on “next generation” of the Internet Protocol, which would be necessary to support long-term Internet growth. This was standardized in 1995 as IPv6[16].

As described above, IPv6 allocations have been made on a neutral and impartial “demonstrated need” basis, and address management policies have required little adjustment since allocations started in 1999. Ipv6 allocations are made uniformly to any organization which demonstrates its requirement, and there is no possibility of “special” allocations being made to any organization, whether Governmental, business or otherwise.

6. Are the special needs of developing countries being taken into account? Can’t we simply reserve IPv6 addresses for use by those countries in future?

Through the RIR policy processes, all stakeholders have the ability to bring concerns to light and to propose solutions for any problems which can be demonstrated. In this way a variety of issues affecting developing countries have been raised and addressed in the past, resulting in policy changes that have supported Internet deployment in those countries (for instance by reducing the size of the minimum IPv4 allocation which can be made, allowing easier access to address space by those in disadvantaged circumstances).

Currently there are no mechanisms for explicit reservation of IPv6 address space on a regional, national or local level.  However, there is nothing to stop such a policy being proposed through the regional or global bottom-up multistakeholder processes. It would then be considered and debated on its merits at the respective regional and global level.

It is notable that each of the RIRs, in accordance with its regional priorities and needs, has placed substantial resources into support for Internet development and capacity building in their regions, and particularly in developing countries. This support has taken the form of targeted and subsidized training programs, conference scholarship support, discounted fees, online resources, remote participation facilities for RIR meetings, and many other measures,. In future, as the IPv6 Internet evolves and grows, the regional address policy processes will all relevant considerations are brought to bear on policy formation, in both developing and developed nations.

7 Would it be better to set up a UN-based of other multilateral organisation to manage IP address allocations?

As the Internet has grown, some Governments and inter Governmental organizations have sought to play a much stronger role in governing its use and ensuring that it is “properly” regulated. This approach has been resisted by the internet community at large, which maintains the view that the imposition of governmental controls would inevitably stifle the currently highly effective network. It has been the experience of many diverse economies, in both developing and developed countries, that successful development of high-capacity, efficient and cost-effective Internet infrastructures has followed from deregulation of the industry in favour of a more self-regulatory and competitive environment.

Industry, working in an environment of vibrant competition at national and global levels, has ensured that the network has grown in the most efficient and effective way, delivering the best content and applications to its users at the best possible price. Civil society has also acted, often at an international level, to ensure that the Internet is put to the best possible uses in serving human development, while being developed and governed in a way which is open, accessible and secure. The multistakeholder, bottom up policy making procedures developed by various non-governmental organizations, formal and informal, has proved to be a successful model which encourages the unique innovative capacity of the internet, without the constraints which would be imposed by the heavier structures of the more traditional international organisations.

8. And what about the future?

The Internet today is a distributed, decentralized, multi-stakeholder enterprise, but one which is also reliable, efficient and secure enough to carry trillions of dollars in value and investment worldwide. Indeed it is argued by many that the success of the Internet has not occurred in spite of its unique mode of coordination, but rather because of it[17].

IPv6 represents a turning point for the Internet, but one which will take another 5 to 10 years to fully materialize. Some may see this transitional period as an opportunity to propose alternative mechanisms for the management of either IPv6 address allocations, or indeed the Internet itself. However in the absence of any evidence or consensus that a new approach would be beneficial, or that challenges related to IPv6 adoption and transition cannot be managed through the systems, the RIRs will continue to operate as proven, open and inclusive, multi-stakeholder organizations; indeed as some of the best examples of effective Internet Governance which can be found in the world today.


1- ISOC Briefing Paper 1, “IPv6 and the Future of the Internet” http://www.isoc.org/briefings/001/

2- From http://resources.potaroo.net/iso3166/v4cc.html

3- A conservative calculation which assumes the equivalence of 1 IPv4 /32 identifier (of which 232 are available) and 1 IPv6 /64 identifier (of which 264 are available)

4- A calculation which follows directly from (4)

5- From the World Bank “World Development Indicators”, Internet user population 1993 to 2007 (http://ddp-ext.worldbank.org/ext/DDPQQ/member.do?method=getMembers&userid=1&queryId=135)

6- RFC1366 “Guidelines for Management of IP Address Space”, http://www.ietf.org/rfc/rfc1366.txt

7- http://www.nro.net

8- See http://www.icann.org

9- ISOC Briefing Paper 10, “The Regional Internet Registry Policy Development Process” http://www.isoc.org/briefings/010/

10- See http://www.aso.icann.org

11- See http://www.apnic.net/policy/nir-criteria

12- See http://www.apnic.net/policy/operational-policies-nirs

13- See proceedings of APNIC 27: http://meetings.apnic.net/__data/assets/pdf_file/0011/8939/pan-nro-stats.pdf (slide 4), and APNIC 25: http://archive.apnic.net/meetings/25/program/igf/wilson-igf2008-where-next.ppt (slide 16).

14- RFC1338 “Supernetting: an Address Assignment and Aggregation Strategy”, http://www.ietf.org/rfc/rfc1338.txt

15- RFC1366 “Guidelines for Management of IP Address Space”, http://www.ietf.org/rfc/rfc1366.txt

16- RFC1886 “Internet Protocol, Version 6”, http://www.ietf.org/rfc/rfc1886.txt

17- http://www.isoc.org/news/4.shtml

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