The industry skipped from IPv4 to IPv6, leaving IPv5 and the Internet Stream Protocol to the annals of history — a data streaming experiment rendered unnecessary by broadband

IPv5 - a dead branch.

The Internet as we know it was born through a series of unexpected developments in networking technology. So it isn’t very surprising that, along its crooked growth trajectory, there were several rather fruitless branches. One such branch was the Internet Stream Protocol (ST), which is also sometimes referred to as IPv5, as tech tidbits Twitterer Laurie Wired recently highlighted. However, the industry has skipped IPv5, moving directly from IPv4 to IPv6, leaving it as a forgotten protocol.

Everyone’s heard of IPv4 and IPv6.I bet you don’t know about IPv5.Designed in the late 70s, it was an experimental protocol by MIT’s Lincoln Labs for real-time streaming.Basically, Zoom before Zoom existed...but for defense: pic.twitter.com/qSbK4LZE1UNovember 19, 2025