Why the need for IPv6? Blame Vint Cerf.

The world is running out of IPv4 addresses, forcing the adoption of a new generation of Internet protocols, IPv6, to keep the Internet running. Whose bright idea was that?

“It’s my fault,” confessed Vint Cerf, godfather of the Internet.

Cerf, now chief Internet evangelist at Google, came to Washington in 1976 as a program manager at the Defense Department’s Advanced Research Projects Agency to help develop a new set of networking protocols, TCP/IP, for the experimental packet-switched network called the ARPAnet. One of the decisions his team needed to make was the size of the address space in the packets.

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Some researchers wanted a 128-bit space for the binary address, Cerf told an audience at a recent IPv6 workshop that the National Telecommunications and Information Agency hosted. But others said, “That’s crazy,” because it's far larger than necessary, and they suggested a much smaller space. Cerf finally settled on a 32-bit space that was incorporated into IPv4 and provided a respectable 4.3 billion separate addresses.

“It’s enough to do an experiment,” he said. “The problem is the experiment never ended.”

Some 34 years later, those addresses are almost used up, and the 128-bit address is being adopted — large enough to provide an exponentially greater number of addresses. It's a number so difficult for the mind to grasp that it typically is described in terms of grains of sand on a beach or golf balls filling the sun.