IPv5 is a term sometimes found in discussions about the development of Internet protocols, but in reality, it was never officially designated as a successor to IPv4 or a precursor to IPv6 in the context of network addressing.

What is known as IPv5 was actually an experimental protocol called Internet Stream Protocol, abbreviated as ST o ST2, and was designed to support the transmission of video and audio over connection-oriented networks, anticipating some of the streaming services we have today.

The Internet Stream Protocol, developed in the 70s and refined through several versions (version 2 was the best known, hence the “2” in ST2), focused on real-time data transmission over the Internet. grid.

This protocol implemented features such as quality of service (QoS) management to ensure data delivery with the bandwidth and latency requirements necessary for continuous media streams.

Although ST/ST2 was an innovative project that introduced many ideas used in multimedia streaming and other later network protocols, it was not established as a de facto standard for network addressing or as a long-term solution to the address shortage. IP, mainly because its focus was more aimed at improving quality of service and support for real-time applications, rather than expanding the available address space.

When the need for a larger address space became critical, development focused on what we now know as IPv6, which offers virtually unlimited address space thanks to its 128-bit design, along with improvements in security, routing efficiency and auto-configuration, among other features.

IPv6 was specifically designed to overcome the limitations of IPv4 and ensure the long-term growth of the Internet, making the intermediate step of IPv5/ST2 more of a historical footnote in network protocol development.