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Demystifying IPv6

- May 30, 2013 - 32 Comments

Version 6 of the Internet protocol (IPv6) is a key enabler of the Internet of Everything (IoE). People, data, and things all need IP addresses to connect to the Internet. But we’ve already run out of IP addresses under IPv4, which dictates almost all (98.5 percent) of Internet traffic today. Even with all of the attention IPv6 has received, confusion and misinformation abound.

I’m extremely pleased to have Mark Townsley, Cisco Fellow and recognized industry expert on IP, explore IPv6 over a series of three blogs.

In these posts, Mark will demystify IPv6, discuss how to best make the transition from IPv4 to IPv6, and take a look “under the hood” of IP so that companies and industries can get the most value from IoE.


I’d like to thank  Dave for this opportunity to write about IPv6. As the Internet of Things (IoT) grows into IoE as people and data join the billions of   devices and machines already connected to the Internet, a smooth and rapid transition from IPv4 to IPv6 becomes even more critical.  And while much work has been done on this front, there is still much to do. In this first blog about IP, I’d like to address the five questions I regularly receive on my blogs, at industry events, and from business executives.

 1.  What is the Internet Protocol (IP) and why is it important to the Internet?
IP is the “lifeblood” of the Internet. If you could “see” information in its raw form as it is exchanged between devices and passes over radio waves, copper wires, and fiber optic cables, you would notice tiny, similar-looking, packages of digital information called IP packets. These packages of 1s and 0s are the fundamental building blocks of the Internet and, in many ways, are analogous to the atoms that make up physical matter or the cells in living creatures.

At any given period of time, there are literally trillions of IP packets zooming across the network. Small bits of “header” information tell routers and switches where the information came from and where it is going so that it reaches its proper destination. This adoption of IP has been nothing short of a revolution in worldwide electronic communication.

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

3. If we did run out of IPv4 addresses last year, why is the Internet still operating and growing?
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 evermore 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.

4. Why is IPv6 important for IoE?
IPv6 brings us a much, much larger playing field on which to efficiently operate. In the case of IoE, 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 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 capabilties 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.

5. What happened to IPv5?
The first four bits of every IP packet contains a number that indicates what type of IP packet follows. These bits are called, for better or worse, the IP “version” field. IPv4 packets have the number 4 in this field (0100), and IPv6 packets use the number 6 (0110).  IPv5 (0101), dates back to a project started as early as 1979 in what eventually became the Internet Stream Protocol. Despite having the number 5 to distinguish it from other types of IP traffic, IPv5 was never considered as a successor to IPv4. IPv6 really is the next iteration of IP.

My next blog will describe the state of IPv6 deployment on the Internet today, and provide insights into how business and technology leaders can make the transition from IPv4 to IPv6 as seamlessly as possible. Please let me know what questions you have about this important transition so I can address them in my next post.

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  1. A complicated and huge topic broken down very well for the layman who really just wants to be versed but not necessarily knowledgable on the topic. It's clearly a necessary upgrade and the inevitable! Looking forward to future articles with updates!

  2. How will this transfer, from IPv4 to IPv6 be for Security's will it create opportunities for Hackers ?

  3. Thanks for the visualization mattered.

  4. Great write up on IPv6. Currently in studies for my Network+ and am wondering if headers and such are now differentiated in a new protocol with IPv6 vs. IPv4. Are there new data layers or is the expanded 128 bit data stream the only difference. Cheers!

  5. Has anybody researched or even bothered to Speculate how this "upgrade"/transition will augment the staggering amount of EMFs in our already toxic & carcinogenic biosphere?

  6. Hi, Pls confirm is there any classification of IPv6 like IPv4? Pls also confirm sub-netting is possible with it or not?

  7. Good Article Dave. Waiting for Next Part of this

  8. Very interesting and through such trying times will this cause a regular internet person or gamily that regularly use these tablets and phones computers etc... to requirevany changre in one household router itself?

  9. Fantastic!!! Quite informative.

  10. Internet service providers (ISPs) have been fairly reticent about adopting IPv6 as there has not been a strong business case: the customers don’t feel a need for it yet, and there is a significant investment in time, training and money to upgrade to support IPv6. The final problem for ISPs is that consumer-grade IPv6 ADSL routers are only just coming on to the market at price points that could be deemed acceptable to home users. Consumers could also view a forced router upgrade as an imposition rather than a sales point. But I agree : we have no other reasonnable choice

  11. The biggest mistake with IPv6 is it is designed to be separate from IPv4. They should have made all IPv4 addresses become a subset of IPv6 addresses (converting and padding with zeros) to make the transition easier. Design it more as an upgrade rather than a system to switch to and run along side of IPv4.

    • I can understand you concern, but consider that infrastructure wise, the amount of work might not be all that different. So, while it sounds nice having the idea of encapsulating IPv4 octets inside of IPv6, overall, forcing it all to be "new" might be better since the overall workload in the conversion to IPv6 isn't that much more. Thus, we get (perhaps) fuller benefits of an all new IPv6 that doesn't have to carry a burden along with it (?). And of course, anytime you clean house, you get rid of "cruft"... so this could eliminate some mess that's out there.

      • Of course, once you get your IPv6 prefix, you can migrate your IPv4's straight in preserving octets if you like. IPv6 address syntax even supports this combo IPv6+IPv4 addressing. Which is sort of nice. So... I'll vote that "being different's" main benefit is cruft removal...

  12. I really liked your article and learned a lot from it. I guess we will have to migrate to IPv6 soon so that we can support the people and machines that will be connected to the internet in the future. I am concerned about how the transition from IPv4 to IPv6 will transpire and would like to know if a single company can transform by itself, or must the world transform. I hope this has been taken into consoderation, and really would not believe it hasn't, so your insight into how we achieve the IPv6 internet would be helpful for planners and implementers.

  13. Will you be offering formulas for working w/IPv6?

  14. In making the transition, must we collectively change? Or can one organization be running on IPv6 and the other IPv4? Thank you for the insight!

  15. In your article you state "IPv6 quadruples the number of bits in the IPv4 address field from 32 to 128.". How can we expect this to effect hardware? Will 32 bit and 64 bit operating systems become obsolete or will they just be less efficient than the next gen?

    • The bits in the processor are not related to the bits on the Internet Protocol. We will still be using the same computers.

  16. Great learning

  17. I'll follow up

  18. Waiting for next part, really interesting.

  19. Love I have one

  20. Have we thought at all about privacy under IPv6, especially in totalitarian areas of the world?

  21. Will I need to upgrade my Home Network to make the switch from IPv4 to IPv6 ? What Router, Cables, Wireless Speed will I need?

  22. excellent article! very articulate and broke down the faq's very well

  23. What can we be teaching little kids now to prepare them for the works of IoE?

  24. This transition has been a long time in coming. Many persons thought, we would never use because of technologies such as NAT. Of course, those thoughts were from an American, whom own about 75% of the IPv4 addresss. In many other countries IPv6 is an accepted standard with ISP. While IPv6 does open new possiblities, it will also bring new challenges. Some, for example, security challenges with IPv6 mobility have been answer. I look forward to the new challenges and new possiblity of the IPv6 world. All I can say, IT IS ABOUT TIME. bh

  25. How to do transition to IPv6 when some devices in our nets for example routers doesn't have IPv6 in their firmware. And how to do it in our houses with small networks (some cable and wifi devices and one router wifi with connection to the ISP)?

    • Artur (May 31 question). See the answer to FAQ#9 on the IPv6 knowledge base

  26. For folks that really get the scale and opportunity of IoE, IPv6 is the only solution from the perspective of scale.

  27. Thanks for a important article in the evolution of Internet! IPv6 opens for a lot of new possibilities that IPv4 lacks. My personal view of IPv6 is that it is designed is in the context of the old worlds Internet, when Client-Server and HTTP played an big role and that includes CoAP, MQTT and REST as well. I think we can find the design elements for the new Internet in the how the brain communicates. Until today has Internet been just a dumb mechanical machine that need to be individual designed for what purpose it should be used. This will not work in a world of billions of billions connected things. We must wake up the consciousness in Internet. We can not rely Internet on old thoughts, we need to renew our mind to create. XMPP is what can give Internet it's consciousness. I think most of us understands how bad the brain would work if it communicated by a Client-Server model..... and not talking about how it would be if we had to design a new nuearl interface (API) every time we want to do something new. The only way to create a infrastructure for IoE is to unlearn everything we every learned about how we use Internet today. HTTP = Mechanical (Client - Server) XMPP = Consciousness (Peer - to - Peer) Food for thought /Rikard

    • What do you think XMPP runs on, pray tell? And XMPP does use client-server architecture, by the way.