Does this remind you of Y2K? The hard reality that the Internet is running out of IPv4 addresses recently hit the Wall Street Journal and New York Times. You know what comes next: business executives get to wondering just how this IPv6 thing will impact their businesses.

When the CEO asks about your plan, will you have a good answer?

You'd better, because the companies that provide your customers with Internet access are on the move. Broadband service providers--cable, DSL, and mobile--depend on a steady flow of new IP addresses as they grow, and they are actively implementing IPv6. Because of these initiatives, a tremendous number of IPv6-equipped end users will be coming online over the next few years.

While top content providers, including Facebook, Google, and Yahoo, are adding IPv6 capabilities to their sites to ensure their services will be available to both IPv6 and IPv4 users, broadband providers understand that, for the foreseeable future, most Internet content will remain IPv4. The dilemma, then, is that they have only IPv6 addresses for their new customers but must ensure that those customers can still reach IPv4 content. The methods they use to solve this problem can affect your business in some surprising ways.

One solution is for providers to deploy centralized network address translators (NATs, either NAT444 or DS-Lite) that allow ISPs to "dual-stack" new customers with a public IPv6 address and a private IPv4 address. The other option is to use a protocol translator (NAT64) that allows an IPv6-only device to talk to an IPv4-only device. Neither method is ideal--both are known to break some applications, such as VoIP, Universal Plug-and-Play, and many online gaming apps. They also can hurt performance and create a single point of failure. Also, applications that identify users by IP address will no longer work if the user is behind a centralized NAT. Because these systems use a pool of public IPv4 addresses rather than public addresses at the individual customer edge, a single public IPv4 address can represent thousands of users.

Where a company could run into problems is when its content or Web applications no longer work correctly because a broadband provider serving its customers is using one of these transitional technologies. The customer doesn't understand the nature of the networks he's using; he only understands that a site he wants to access is not working correctly. Sure, it may be the service provider's fault, but you can bet he'll blame the one running the Web site--yep, that means you.

Potential damage to the user experience is the main reason for beginning an IPv6 deployment plan.