World IPv6 Day is here, and with it many ISPs, websites and manufacturers are now supporting IPv6, the next generation network protocol of the internet.
For many users, though, the questions of what, when and why still await answers.
Everyone in networking knows that they should be switching to IPv6. The Internet Engineering Task Force (IETF) realized that in 1994, when it predicted that IPv4’s 4.3 billion addresses wouldn’t be enough. Its answer was IPv6. With its 128-bit address space it can have up to 2^128 addresses — that’s 40,282,366,920 billion billion billion usable addresses. Even an interstellar internet won’t run out of numbers any time soon.
Meanwhile, back on Earth, the regional internet registries (RIRs) in charge of parceling out IP addresses are down to their last old-style IPv4 addresses. Indeed, the Asia Pacific Network Information Center (APNIC) ran out of IPv4 addresses in April 2011. RIPE NCC, Europe’s RIR, will be the next to run out sometime in August. In North America, the last IPv4 address will be assigned in June 2013.
That will be the end of the road for new IPv4 addresses. Technologies like Network Address Translation (NAT) and Classless Inter-Domain Routing (CIDR) that let us run multiple devices behind a single IP address have won us some time, but while neither NAT nor CIDR will be going away soon, they can’t delay the IPv4 famine any longer.