In the early 1990s, internetworking wonks realized the world was not many years away from running out of Internet Protocol version 4 (IPv4) addresses, the numbers needed to identify any device connected to the public internet. Noting booming interest in the internet, the internet community went looking for ways to avoid an IP address shortage that many feared would harm technology adoption and therefore the global economy.
A possible fix arrived in December 1995 in the form of RFC 1883, the first definition of IPv6, the planned successor to IPv4.
The most important change from IPv4 to IPv6 was moving from 32-bit to 128-bit addresses, a decision that increased the available pool of IP addresses from around 4.3 billion to over 340 undecillion – a 39-digit number. IPv6 was therefore thought to have future-proofed the internet, because nobody could imagine humanity would ever need more than a handful of undecillion IP addresses, never mind the entire range available under IPv6. //
"IPv6 was an extremely conservative protocol that changed as little as possible," APNIC chief scientist Geoff Huston told The Register. "It was a classic case of mis-design by committee."
And that notional committee made one more critical choice: IPv6 was not backward-compatible with IPv4, meaning users had to choose one or the other – or decide to run both in parallel.
For many, the decision of which protocol to use was easy because IPv6 didn't add features that represented major improvements. //
While IPv6 didn't take off as expected, it's not fair to say it failed.
"IPv6 wasn't about turning IPv4 off, but about ensuring the internet could continue to grow without breaking," said John Curran, president and CEO of the American Registry for Internet Numbers (ARIN).
"In fact, IPv4's continued viability is largely because IPv6 absorbed that growth pressure elsewhere – particularly in mobile, broadband, and cloud environments," he added. "In that sense, IPv6 succeeded where it was needed most, and must be regarded as a success." //
But there are plenty of organizations that still see a need for IPv6. Huawei sought 2.56 decillion IPv6 addresses and Starlink appears to have acquired 150 sextillion, which is helping to push more countries past 50 percent IPv6 adoption.
