IPv4 vs IPv6: The Road Ahead

jeffy124 writes "With the world moving towards having every device under the sun being Internet-connected, is the Internet going to be too large? This article off CNN.com examines this potential situation. They look into the problems of switching networks from IPv4 to IPv6, and the inclusion of inter-operability between the two. Benefits of moving to IPv6 are looked at, but so are the critics of it who point out that if we don't have a problem now, why fix it? While low of technical details, the story points out that not many systems out there currently support IPv6. "

Comments

Re:More IP address !=more ease

[jd]

Doesn't work that way with IPv6. IPv6 uses a system whereby the provider announces a prefix to the device, and the device then attaches whatever number it likes to that prefix. If another device attaches to that first device, then that first device announces the prefix it got, PLUS the first 1-2 bytes of whatever it added, as the new prefix.

The theory behind all this is that you can then move a device from one network to another, without ever having to worry about routing problems, IP numbers colliding, or other such mundane trivia.

"Permanent" addresses, in this system, don't exist. They're all calculated.

How does this work, in practice?

Well, let's say that Joe Bloggs is connected to AOL. AOL decides that the backbone provider it uses can get stuffed, and switches. This changes all of AOL's addresses, and therefore Joe Bloggs' address.

However, because addresses have a lifetime attached to them, the old address remains active (although forwarded) for a finite length of time, although new connections to the old address are prohibited.

Because of this, it makes no sense for some central registry to store AOL's IP number. It can change once every 60 seconds, along with the IP address of everyone/everything connected via it.

The only person who can meaningfully store AOL's IP address becomes AOL, itself. Nobody else can possibly know it, with any reliability.

Normally, ISPs and large corporations aren't going to flip around like that. But they -can-. The protocol permits it. Because of that, and because uptime is increasingly important, they will then be able to shop for a secondary provider for a backup link, in case the first one dies.

In IPv4, a backup link via an alternative provider would be lethal. There would be no way to handle the changes in addressing, unless the entire ISP or company was behind a NAT system with High Availability at the IP level, which causes its own problems.

With IPv6, the change-over would take under 5 seconds for the whole of AOL. Nobody would notice the delay, nobody would get disconnected, and the whole setup is much simpler.