What the Heck is IPv6?

You may have heard or read something about World IPv6 Day or about the longer-term transition to IPv6. If so, you may be scratching your head and asking, “What is this all about?”

This primer is for you.

Below, we summarize some background information and terminology related to IPv6. We’ve tried to keep that summary as simple as we can, but it’s almost impossible to tackle (and understand) this subject without using a few technical terms.

After the backgrounder, we list the steps Suddenlink will be taking to prepare for the IPv6 transition.

Finally, we note some additional questions you might have and offer some answers.



All content on the Internet (websites) and all devices connected to the Internet (computers, modems, routers, smart phones, etc.) have an Internet Protocol (IP) address.

Today, virtually all consumer devices and websites use IPv4 (Internet Protocol version 4) addresses.

Those addresses are managed by the Internet Assigned Numbers Authority (IANA), an operating unit of the Internet Corporation for Assigned Names and Numbers (ICANN).

  • The IANA issues or assigns IPv4 addresses to regional Internet registries.
  • In turn, the regional registries issue or assign IPv4 addresses to website developers and Internet service providers (ISPs) like Suddenlink.

In February this year (2011), the IANA issued the last 16 million IPv4 addresses to the regional registries. Since then, the IANA has been issuing only IPv6 addresses.

Essentially, IPv6 is a new addressing scheme, and initially, it will offer no enhancements or improvements to the typical consumer Internet experience.

IPv6 addresses are not compatible with IPv4 addresses.

  • In other words, a computer with only an IPv4 address cannot access or “read” a website with only an IPv6 address.
  • Likewise, a computer with only an IPv6 address cannot read a website with only an IPv4 address – at least, not without some assistance.

The good news is that, to the best of our knowledge, all consumer websites today have IPv4 addresses. Some of those sites also have IPv6 addresses – and more will have IPv6 addresses in the future — but we fully expect they will keep their IPv4 addresses active for quite some time.

  • In other words, we expect consumer websites (especially the most popular consumer sites) to use both IPv4 and IPv6 addresses for many years to come because they want to make sure their visitors have access to their content, regardless of the type of IP addresses that are assigned to their visitors’ computers, smart phones, etc.



Suddenlink has been — and will continue — working diligently to make a smooth transition to IPv6 so that our customers can continue to visit their favorite websites and use their favorite online services.

In the first phase of our transition, we will begin the process of assigning two IP addresses to customer modems, routers, etc. One of those addresses will be IPv4 and one will be IPv6.

In the second phase of our transition, we will begin the process of assigning IPv6 addresses to devices that are capable of using (accepting) those addresses and then using Network Address Translation (NAT) technology for connections between those devices and websites that only have IPv4 addresses.

Editor’s Note: Contrary to estimates provided in an earlier version of this post, the timing of these two phases has not yet been finalized nor confirmed.



Q: What about websites that are created in the future? Won’t some of them be offered only in IPv6?

A: At some point, yes, but we believe that point is many years down the road.

It’s important to remember that — even though all IPv4 addresses have been issued by the IANA (Internet Assigned Numbers Authority) — each new website only needs a few IP addresses, at most, and new website developers should still be able to obtain IPv4 addresses from other sources, such as other website developers or hosting services that have a reserve of unused IPv4 addresses.

In short, we believe websites will continue to have IPv4 addresses for years to come.

Q: Do Suddenlink customers need to do anything to make the transition to IPv6 possible?

A: Most customers should not need to do anything. However, if your computer has an old operating system, you should consider upgrading to a newer system, like Windows 7 or Mac OS X 10.6. Older operating systems, like Windows 95, will not recognize IPv6 addresses.


  1. John Laur says

    You are planning on stranding users on ipv6 as early as 2012? Please. I hope you have one heck of a 6to4 strategy since nobody is successful with one yet outside of China; and you know how well it’s working there. This is not exactly the news I was expecting the last time I asked about SL’s ipv6 plans…

    • FYI Publisher says

      No one should be stranded. Any customers with IPv6-only addresses will also be on a network with NAT device(s) so they can continue visiting websites with IPv4 addresses. We will test and re-test all aspects of this effort before implementing it.

  2. Michael Reilly says

    Excellent news. A couple of questions.

    Will I be assigned a /64 IPv6 prefix?

    How will my router be assigned an address – DHCPv6 similar to how it obtains its IPv4 address today?

    If I want to use IPv6 autoconfigure eui-64 address assignment for my home subnets will I be able to get a larger address space? (I current have a /48 from my IPv6 tunnel broker.)

    • FYI Publisher says

      Thanks for your questions. Given their technical nature, we will answer in largely technical terms. However, please don’t hesitate to leave a follow-up comment or question, if any of this response requires clarification.

      First of all, yes, we will use DHCPv6 to assign dynamic IPv6 addresses.

      Second, as we transition to IPv6-only addresses, if you have a single PC behind a cable modem, you will be assigned a single IPv6 address. (Most desktop operating systems are not capable of being assigned a block of addresses.) If you are using a router/wireless gateway that is capable of supporting “DHCPv6-PD” (PD = prefix delegation), then you will be assigned a single IPv6 address for the “outside” (Internet-facing) connection and a block of IPv6 addresses for the “inside” (customer-network) interface.

      Finally, we understand that ARIN (American Registry for Internet Numbers) is currently voting on a policy that would allow Internet service providers (ISPs) the ability to assign larger blocks (/48’s) to their customers. ARIN’s advisory committee has recommended adoption of this policy and we expect their board will follow suit. Assuming this policy passes, we should be able to assign up to a /48 per customer. If the policy does not pass, our current allocation from ARIN allows us to issue up to a /56 per residential customer.

  3. Michael Reilly says

    Thank you for the reply and for the information.

    Excellent! Exactly what I was hoping for.

    I think for most home users with a router a /56 would be fine. Of course a /48 will also work.

  4. Tas says

    A /64 block for 99% of all users will work fine
    But the good news is they are working on launching ipv6