With the last IPv4 addresses about to be allocated, the good news is that IT managers -- at least in the U.S. and Europe -- don't suddenly have to get the next Internet Protocol working.
The bad news is that there are some hazards both in putting off adoption of IPv6 and in implementing it, according to vendors and industry analysts.
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If the Asia-Pacific Network Information Center is granted two more large blocks of IP addresses, which it is entitled to because its addresses are being snatched up so fast, then a rule will kick in that forces the Internet Assigned Numbers Authority (IANA) to divide the remaining five blocks of IPv4 addresses among the world's five regional registries. Once the regional bodies run out of those addresses, they will have nowhere to turn for new ones.
IPv6, introduced in the late 1990s, offers an almost unlimited number of addresses, compared with approximately 4.3 billion addresses for IPv4. While many devices use privately held addresses that are reused on the same LAN, unique IP addresses are usually needed for servers and other types of endpoints. Particularly in fast-growing parts of the world, such as India and China, those unique addresses are being consumed quickly. The two versions aren't compatible, so, for example, client systems that only have an IPv6 address can't get to content on servers that only have IPv4 addresses.
Yet despite the dire state of IPv4, the use of IPv6 is still minuscule, according to Arbor Networks, which supplies network monitoring equipment to about three-quarters of all large Internet service providers (ISPs).
The results of Arbor's last survey of the Internet, about five months ago, show only a fraction of one-tenth of 1 percent of all traffic used IPv6, "almost below the threshold of what we could measure," Arbor Chief Scientist Craig Labovitz said.
Part of the reason is that migrating to IPv6 costs money and in most cases offers no economic benefit, observers said. However, it will take cooperation from everyone to prevent the first IPv6-only Internet users being cut off from most of the world's Internet hosts, said Jason Schiller, a senior Internet network engineer at Verizon Business. He fears some user, somewhere, may be in that predicament in the next six to 12 months if nothing is done.
That's not likely to happen to enterprises in North America or Europe, analyst Glen Hunt of Current Analysis believes. For one thing, major U.S. service providers will have IPv4 addresses to give out to their customers for some time, he said. Also, through large-scale NAT (network address translation), the carriers could also act as bridges between the IPv4 world and users who can only get IPv6, according to Hunt. With NAT, users can share a single, unique IPv4 address that is exposed to the outside Internet.