What is IPv6 and why should I be concerned about it?

Mark Townsley – Cisco Fellow

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IP was originally developed in an advanced research laboratory. There were several earlier versions that predated the use of IPv4, which became commercially popular in the 1980s and 1990s and which is broadly used today. IPv6, the latest IP version, was developed to address several challenges of its predecessor. Most important, IPv6 overcomes the fundamental limit of 4.3 billion globally unique addresses that has been present in IPv4 since its inception in 1981.

Because the Internet is so engrained in our lives, it is critical that we migrate from IPv4 to IPv6 without disruption, an equally challenging and important task. I sometimes compare this task to swapping out the wheels on a high-speed train without alarming the passengers.

Whether you are an IT professional, technology enthusiast, or business executive, I believe it is important for you to be well aware of the limitations of globally unique IPv4 addresses and the move to IPv6 which is currently underway. These topics are important because they will greatly influence the future growth of the Internet for the billions of people who rely on it to live, learn, work, and play.

Imagine an enormous playing field with 4 billion unique squares in a grid. Now, visualize large groups of squares being assigned to various organizations, businesses, and Internet service providers. Next, picture individual squares within these groups being populated by PCs, laptops, tablets, smartphones, servers, and other computing devices. Finally, imagine that you can rapidly and efficiently send a packet of information to the devices that reside in any square.

Because the number of squares is fixed at approximately 4 billion (as in IPv4), adding more and more devices to the playing field makes it ever more crowded. While all of the devices can fit for a while, the system inevitably stops growing and becomes less efficient. This is where we are with the Internet today—IPv4 is still working, but we need a new chessboard (IPv6), so to speak, if we want the Internet to continue growing and functioning as we expect it should.

IPv6 brings us a much, much larger playing field on which to efficiently operate. IPv6 allows for a nearly limitless number of IP addresses, which will be required to connect the tens of billions of people, process, data, and things that will make up the Internet of Everything (IoE).

Specifically, IPv6 quadruples the number of bits in the IPv4 address field from 32 to 128. This increases the number of networks that can be reached directly as well as allows for automatic configuration of IP addresses connected to a given local area network (LAN). All in all, this change gives us more capabilities as well as a theoretical playing field of 2^128 squares in which to put devices—enough, in fact, to put every atom on the surface of earth into its own square more than one hundred times over.

Virtually all modern operating systems used by people today—Windows Vista, 7 or 8, Apple Mac OS X or iOS, and Google Android—are dual-stack, meaning they support both IPv6 and IPv4. This large installed base was “step zero” in the transition to a new Internet Protocol. The next steps were World IPv6 Day in 2011 and World IPv6 Launch in 2012. In just over two years, we have entered a phase of progressive uptake, and are poised to reach 50 percent IPv6 adoption within five years.

While the “human” Internet we know today has begun its transition from IPv4 to IPv6, there is another Internet of “things” that is beginning to emerge from a multitude of incompatible, often proprietary protocols that have been fragmenting the industry. As the Internet of Things emerges, it will embrace IPv6, and skip over IPv4 entirely.

Successfully completing the transition to IPv6 will require the ongoing commitment and vision of every network operator, device manufacturer, software developer, and anyone else who develops Internet-based technology.

An industry-recognized Internet Engineering and Broadband Architecture expert, Mark Townsley
joined Cisco in 1997 and is one of sixteen Cisco Fellows.

Mark has been actively involved in Internet industry forums since 1995. His leadership appointments
have included: two terms as Internet Area Director of the IETF from 2005-2009, IETF L2TP Working
Group Chair from 1999-2005, IESG Liaison to the Internet Architecture Board (IAB), IETF Pseudowire
WG Technical Advisor, and co-Chair of the newly formed IETF Home Networking Working Group
(Homenet). Mark also serves as an Ambassador of the Broadband Forum, and was invited to speak to
the FCC on IPv4 Exhaustion and IPv6 in June 2011.

Mark is currently focused on the effects of IPv4 exhaustion and on removing barriers to IPv6
deployment for Cisco customers and the industry at large.