By Louie Lee

You’ve been reading my blog posts and are finally convinced that you should adopt IPv6 in your network.

Okay, maybe you’re not convinced, and you’re just reading my posts for entertainment value. In any case, it will likely take a better part of the decade (or longer) to make the full transition from IPv4 to IPv6.

During this transition period that we are already in, a few things will happen, and they may play a significant role in determining the course of the global effort to continue Internet growth.

A very interesting article was recently written by Geoff Huston on the uncertainties around this IPv4-to-IPv6 transition period.  He has put forth some questions on the viability of the long term plan that we actually complete the transition. His thoughts began with an idea that I had summarized in my earlier blog post:  The catch is that IPv4 and IPv6 are not compatible.

In other words, if you are using IPv4 on your computer, and the other end is using IPv6, you can’t talk to each other… without something else.

CGNs, CDNs, ALGs – Oh My!

Many of us with home Internet access are familiar with the home router that let’s us connect several devices (via wired-Ethernet or WiFi) to the Internet.

Most home routers employ a network address translation (NAT) technology to let you use the single ISP-assigned IP address with several devices.

In much the same way, Carrier Grade NAT (CGN) technology is being developed to allow ISPs to provide service for their customers between the IPv4 Internet and the IPv6 Internet.

Performance through CGNs of today is still degraded, and certain end-to-end features in IPv6 wouldn’t be available. As the transition period continues, we expect to see content relocated from IPv4-only sites to v6-enabled Content Delivery Networks (CDNs). Much of the Internet’s commercial media (stored and streamed) are already stored on CDNs. (Ever bought a song for your computer or portable MP3 player? Viewed a popular user-uploaded video? You’ve used a CDN.)

We may even see network providers resorting to Application Level Gateways (ALGs) to front-end IPv4-only services on an IPv6 Internet.

Permanently Temporary, or Temporarily Permanent?

The fear is that as network providers invest in these transition technologies, they may be motivated to protect that investment and extend the period of this temporary situation. Have you ever put off buying that new car thinking that you can make the old car run another few months? Did that few months turn into a year? Could that old car get you everyone you wanted to go in the end?

And beyond just protecting that investment, what if the network providers begin to derive more revenue from these transition services. Is it possible that we will find ourselves locked into this state — never to break ourselves out of the IPv4 world?

Mr. Huston reminds us that in this deregulated and highly competitive environment, decisions are being made from different parts of this industry based on their own perspectives:

If the hope here is that there is some overall plan of a coordinated response to IPv4 exhaustion and the associated transition to IPv6, then it is useful to bear in mind that there really is no plan at all, and all we have instead is the interplay of market pressures and their outcome.

Mr. Huston’s perspective is interesting in that he hails from the region of the world where IPv4 addresses have effective run out. Evidence of this transition progression is already beginning to show in the Asia-Pacific region.  

His projections put the European IPv4 run-out date in the in 1Q2011.

He expects the same thing to happen in North America in mid-2014.

Projected Regional Internet Registry Address Pool Exhaustion Dates
Source: http://www.potaroo.net/tools/ipv4 (14-Sep-2011 07:59 UTC)

“It’s not happening unless it’s happening to me!”

For too many in the IT industry, the rest of us IPv6 advocates are claiming that the sky is falling. They don’t realize that the sky has already fallen for our friends in the Asia Pacific.

Mr. Huston proposes that the more time, money, and effort we invest into ways to still use IPv4, “the higher the risk that we will lose track of the temporary nature of transition and the higher the possibility that we’ll get stuck with the wrong Internet at the end!”

If we are to keep the Internet growing and evolving through an IPv6 Internet, then we must implement IPv6 quickly rather than extending the usefulness of IPv4.