As I mentioned in a previous column on IPv6 adoption, enterprises are taking a slow approach, so don't expect to see a wave of new IPv6-enabled sites. I want to highlight some aspects of IPv6 deployment that enterprises may want to consider with respect to public content:
Enterprises design networks much differently than service providers and content providers. Enterprise networks are private networks that connect data centers, head offices and branch offices. The network connectivity for many enterprises is MPLS/VPN, which allows the use of RFC 1918 IP address space. The closed nature of these networks is one reason many enterprises lack an IPv6 strategy.
An enterprise's Internet presence is the primary exception. When you think about content providers, you probably don't think about enterprises. Yet some serve massive amounts of content to the general public on the Internet. For this aspect of their businesses, enterprise architects must think like content providers, particularly in regard to customers that must access a company's content over a network that's moving toward IPv6.
Few IPv4 addresses remain. For internal use, RFC 1918 addresses may suffice for years. What happens when the first use with only a public IPv6 (that is, no IPv4 address) can't reach www.yoursite.net? I don't envy those who find themselves having that conversation with the CIO. This is not as far-fetched as it sounds. Some users in Asia already have IPv6-only connectivity. While market reality may dictate that ISPs provide translation mechanisms for IPv6-only users to access the IPv4 Internet, I believe that the need for business continuity will push enterprises to host content over IPv6.
For enterprises that host their primary websites internally, the onus is on the IT staff to prepare the data center and server infrastructure for IPv6. There are many great articles available on IPv6 migration about reaching the IPv6 Internet, so I won't repeat the steps required to enable the Internet edge and data center for IPv6.
The Path From IPv4 to IPv6 Adoption
There's wide consensus among IPv6 experts that shortcuts in IPv6 deployment cause harm. In the context of Web content, these shortcuts can prevent customers from reaching your site or severely degrade the user experience to such an extent that visitors will not return to your website.
Let's use an example of a company that purchases a dedicated ISP link to its data center for IPv6 connectivity. The network path within the data center does not match the IPv4 path. Separating IPv4 and IPv6 topology within the data center seems like a quick and easy method to offer content over IPv6, right?
I advise against this approach. Creating a bifurcated topology has disadvantages in this case. Since operating systems will prefer IPv6, all visitors with dual-stack systems will use the IPv6 path. If you don't have the load balancers and other infrastructure in place for IPv6, the user experience might be degraded. In addition, consolidating IPv4 and IPv6 portions of your data center will be difficult when you decided to merge them. Avoid this messiness with a congruent IPv4/IPv6 topology.
Enabling IPv6 on popular Web servers such as Apache and IIS is simple. If only all aspects of making a site available over IPv6 were so easy! The days of static HTML pages are long past, so your system administrators will have their work cut out for them in ensuring that all supporting systems and scripts function with IPv6. If you have Perl or PHP scripts that assume visitors' source IP addresses are the familiar IPv4 dotted quad, these scripts will not log or process IPv6 source addresses. Will IPv6 adoption cause problems for your content management system? What about billing and security? There's no doubt that your sysadmins have their work cut out for them.
Enterprises that outsource their websites have an easier path to IPv6. While there are not many consumer-grade hosting companies, many of the upper-tier hosting companies have IPv6 infrastructure in place. Managing the vendor in making your content available over IPv6 allows you to invest your time in testing IPv6 reachability, which is a must whether the site is hosted internally or externally. If your hosting company has IPv6 on its road map, insist that IPv6 be included on the contract. I've seen vendors claim that IPv6 is six months out--for multiple years.
If you have not started the planning process to make your content available over IPv6, consider the resources you'll need and budget accordingly. Use the publicity surrounding World IPv6 Launch to highlight the motivations behind the transition to IPv6. In my work with IPv6 and in talking to others in the industry, I found that the business continuity argument is the most compelling. For enterprises that do business on the Internet, the ability to continue to do so will require IPv6-enabled content.