“When you look at the massive size of IOS, with over 2,500 features, if every single one needs to be re-written to support IPv6, that takes time,” Conover said.

One feature that has taken time to land in IOS involves time itself. The Network Time Protocol (NTP) is now available in IPv6. Conover noted that it was previously not supported by IPv6 and needed to be re-written.

Security is also now being improved in Cisco IOS for IPv6 with a technology called first hop security. Aladin explained that a possible risk that had existed with IPv6 before was that another device could have been sitting on a network, spoofing a user’s address. First hop security provides a degree of authentication, to ensure that the address server is authentic and the user can trust the IPv6 address information.

Cisco is now also leveraging the Location/ID Separation Protocol (LISP) to help network administrators deploy IPv6 with IPv6 over IPv4 tunnels. LISP is an emerging standard for routing Internet traffic.

Who Wants IPv6?

With the exhaustion of the free pool of IPv4 address space, the need for IPv6 is now well understood. According to a Cisco survey of 101 U.S IT leaders, 78 percent are currently planning for an IPv6 transition.

Security is the top concern in IPv6 transition efforts with 92 percent of survey respondents noting that their IT organization’s security department is part of the IPv6 migration.

As organizations move to IPv6 though, they still expect certain things to work that did in the IPv4 world.

“When we talk to customers — they tell us they want to implement IPv6, but here is a list of things that I can do with IPv4, and unless I can do them in IPv6 I can’t make the transition,” Aladin said.

Sean Michael Kerner is a senior editor at InternetNews.com, the news service of Internet.com, the network for technology professionals.