The looming depletion of Internet addresses has split the networking world into "IPv4 diehards" and "IPv6 purists," but the real needs of businesses lie somewhere in between the views of these extremists, a Brocade Communications Systems executive said this week.

Speaking on Tuesday to the Brocade Technology Day Summit, Director of Product Management Keith Stewart said many Brocade customers are grappling with the issue of IP (Internet Protocol) address migration.

"As organisations embarked upon that journey, we found many felt that there was a lack of a pragmatic point of view on how to manage that transition. The market was dominated by conversations at opposite ends of the spectrum," Stewart said.

IPv4, the addressing scheme used in most of the Internet today, is limited to about 4.3 billion unique Internet addresses, and most of those have already been assigned. PCs, servers, phones and other devices that use the Internet need an IP address to communicate, and soon they may only be able to get addresses from the next generation protocol, IPv6. The announcement in February that the global Internet Assigned Numbers Authority (IANA) had assigned its last large blocks of IPv4 addresses to regional registries placed this fact in sharp relief. However, reaction to the trend has come down on two extremes, according to Stewart.

The "IPv4 diehards" think that the current addressing scheme can be extended forever through NAT (network address translation) and there is no economic incentive to move to IPv6, he said. The "IPv6 purists" believe all organisations should move to the new protocol in the next 18 months. "That's simply not economically viable," Stewart said. It's also not realistic to think NAT will take care of all the IPv6-only client devices that enterprises will want to reach in the coming years, he said.

"We believe that exhaustion is real, but that most organisations have time to plan and execute their strategies," Stewart said. And administrators should get ready for a long transition, broken into several stages. "A two-protocol world is the world in which we will live for the next decade," Stewart said.

Stewart summed up the debate well, according to analyst Michael Howard of Infonetics Research, who saw the presentation. Moving to IPv6 while remaining visible to IPv4 users involves a lot of unanswered questions and unknown costs, Howard said. While some enterprises and service providers are already taking the plunge, most are scared of what the move will entail, he said.

Not surprisingly, Brocade said it has some tools to help customers navigate the transition. For example, the Brocade ServerIron ADX Series, which it calls an "application delivery switch," can be used to present an organisation's existing sites and services to IPv6 users. Brocade also has a NAT gateway for translating IPv4 to IPv6 addresses, which it developed for a cable operator that needs to deliver IPv6-based video-on-demand products over existing set top boxes that can only use IPv4. These products are available now, Stewart said.

Brocade claims it is the first and only major technology vendor to make its web presence, mail presence and DNS (domain name system) presence on the Internet available via both IPv4 and IPv6. Economics helped drive the company to this point, Stewart said. The US government, a big Brocade customer, is starting to give preference to IT vendors that have proved their IPv6 capability by implementing the new protocol themselves, he said.