The Mystery of the Missing IPv5: Why We Jumped Straight to IPv6

We have all heard about IPv4 and IPv6, but what about IPv5? Did it become obsolete? Was there an IPv5 ever to even begin with? If yes, then what happened to it? If not, then why did we skip it?

But before anything else, we must know what "IP" in IPv4 and IPv6 signifies. The IP stands for Internet Protocol, which is a protocol that has two primary functions, the first addressing and the second fragmentation. We transfer information on the internet via packets, a collection of data that travel from one device to another. On a network, assigning a unique number to each device (source or destination) for identification is called addressing. When a large packet of data needs to be transmitted, it's broken down into smaller, more manageable pieces. This process of breaking large packets into smaller ones is known as fragmentation.

When discussing Internet Protocol versions, there weren't strictly separate versions before IPv4. Instead, they were more like developmental stages leading to IPv4. When it comes to IPv5, it simply doesn't exist. The term IPv5 has no standing whatsoever. When someone is talking about IPv5, they are referring to The Internet Stream Protocol, or ST for short. It is a family of experimental protocols, first defined in 1979. These experimental protocols, designed for streaming video and voice over the internet, used a packet structure similar to IP. To differentiate them, engineers assigned the number 5 in the version field. Consequently, to avoid confusion about which protocol to use, the successor to IPv4 had to be named IPv6.