One ISP, Hurricane Electric, plans to offer NAT64 as a managed service, with the IPv6 address residing in its own data centers. Enterprises will be able to run their own servers on IPv4 and rely on Hurricane to link them to IPv6 users, according to Martin Levy, Hurricane's director of IPv6 strategy. All the enterprises will need to do is add an entry to their DNS server, he said. Some Hurricane clients are already using the service in early release and will be using it on World IPv6 Day on Wednesday.
8. How long can I keep my company on IPv4?
As the supply of new, unique IPv4 addresses dwindles, some enterprises and service providers will use traditional NAT (network address translation) to conserve the addresses they already have. This technique, already used in everything from corporate LANs to home broadband routers, allows multiple clients on an internal network to share one or a few unique IPv4 addresses to talk to the Internet. Each shared IP address could keep as many as a few hundred systems chugging along without the need for new IPv4 or IPv6 addresses. In any case, IPv4 and IPv6 are expected to coexist on the Internet for many years to come.
9. So why don't we just use NAT instead of making people migrate?
NAT typically uses a stateful firewall, which has to maintain information about the ongoing Internet sessions that all the systems sharing an address are using, ICANN's Vegoda said. The capacity of the appliance limits how many sessions it can keep track of, and if it reaches the limit, long-running sessions may be dropped. While this might not affect a five-minute YouTube video, it could cause problems for watching a full-length movie. In addition, some Internet applications use many sessions at once. For example, an online map may use a separate session for every tile of the map image, Vegoda said. If any of those sessions is broken, it could delay completing the map.
NAT64 doesn't have to maintain state information. It is fundamentally different from traditional NAT and really shouldn't even share its name, according to Hurricane Electric's Levy. But even that technology can be a bottleneck. "If you put a box between source and destination of any variety that is interpreting the packets, you are going to affect the quality of the communication from one end to the other," Levy said.
10. What will World IPv6 Day prove?
Google, Facebook, Yahoo and 315 other companies, agencies and universities will provide Web content over both IPv6 and IPv4 for 24 hours. This will allow people who have IPv6 clients to use them to access many different sites. The idea is to expose any technical problems, such as misconfigurations in end-user equipment or software problems at carriers, that could keep users from getting on the Internet using the new protocol.