Feature Story

World IPv6 Day Will Test the Readiness for Change

by Steve Wildstrom

On Wednesday, June 8, the technicians, engineers and content providers who rely on the internet's viability will conduct a grand,global  experiment. For more than a decade, an alternative to the internet's standard communications protocols has been under development and testing in private networks. On World IPv6 Day, Internet Protocol Version 6 (IPv6) will go live for a day on the public internet. "We're going to turn it on everywhere, at least for 24 hours, and see what happens—see what breaks," says Google Vice President Vinton G. Cerf, who co-authored the original internet protocols in the 1970s.

Chances are some things will break but that most internet users won't notice. Some web sites might temporarily disappear because some networks may try, but be unable, to connect to the new-style addresses. The real purpose of the test day is to discover the impact of a large-scale shift to IPv6 on the millions of servers, routers, and switches that make up the internet.

The inertia that has resisted the deployment of IPv6 for years is finally being overcome by a simple reality: The 4 billion or so internet addresses available under the older IPv4 protocol have been exhausted. IPv6 offers an address pool that is, for all practical purposes, bottomless even if every person on earth has billions of devices that need network addresses.

IPv6 addresses are 128 bits long, compared to 32 bits for IPv4. A computer with an IPv4 address of (a typical "private" address on a home network) might get a v6 address of 2001:0000:4137:9e76:100c:0bf4:3f57:fef7. (That's a base-16, or hexadecimal, number; the letters a-f represents digits for 10 through 15.)

But the new protocol offers additional advantages. It has built-in provisions for security, particularly data encryption, missing from IPv4. Devices assign themselves addresses automatically when they connect to a network, eliminating the need for a server (typically built into a wired or wireless router in home networks) to keep track of assignments. (In my experience, address assignment problems are the source of a large share of the difficulties on home networks.) And IPv6 is designed to let devices connect to multiple networks simultaneous. Making mobile communications easier.

The trick remains getting from here to there. Most large enterprises should be largely or completely IPv6-enabled, since all computers and operating systems from the past few years are compatible with the new protocol, as are many commercial routers and other network gear. Homes and smaller businesses are more problematic. The computers are mostly ready, but home networking gear may not be. Residential internet service providers are also far from ready; and success is dependent upon IPv6 being available on their networks, so many are upgrading and testing .

What is going to happen on June 8? Until now, the great majority of servers on the internet have been running only IPv4. Test IPv6 servers typically have names like ipv6.server1.test-ipv6.com and are invisible to the IPv4 network. (That's a real address; if you can reach it, you are fully IPv6-enabled. You can test your computers' and network's readiness here.) On World IPv6, participating companies, which include most of the biggest players in the tech industry, will turn on IPv6 addressing on their regular servers, meaning that both addressing schemes will be active simultaneously on the same machines. In theory, devices using v4 addresses should reach these servers using the older protocols and the relatively few systems using v6 will connect with the new. In practice, some systems will probably try to use v6 and will run into a roadblock somewhere along the way. It's those network problems that the test is supposed to detect.

Eventually, some servers and sites on the net will become IPv6 only. Fortunately, there are tools that will allow IPv6-enabled systems to connect with each other by "tunneling" through IPv4 networks. But that is not likely to become an issue for at least a year or two.

In the end, the conversion to the new addressing system is likely to take place out of the sight of most internet users. But the result will be a better and more efficient network for everyone.

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