The Protocol Wars were a long-running debate in computer science that occurred from the 1970s to the 1990s, when engineers, organizations and nations became polarized over the issue of which communication protocol would result in the best and most robust networks. This culminated in the Internet–OSI Standards War in the 1980s and early 1990s, which was ultimately "won" by the Internet protocol suite (TCP/IP) by the mid-1990s when it became the dominant protocol suite through rapid adoption of the Internet.
In the late 1960s and early 1970s, the pioneers of packet switching technology built computer networks providing data communication, that is the ability to transfer data between points or nodes. As more of these networks emerged in the mid to late 1970s, the debate about communication protocols became a "battle for access standards". An international collaboration between several national postal, telegraph and telephone (PTT) providers and commercial operators led to the X.25 standard in 1976, which was adopted on public data networks providing global coverage. Separately, proprietary data communication protocols emerged, most notably IBM's Systems Network Architecture in 1974 and Digital Equipment Corporation's DECnet in 1975.
The United States Department of Defense (DoD) developed TCP/IP during the 1970s in collaboration with universities and researchers in the US, UK and France. IPv4 was released in 1981 and was made the standard for all DoD computer networking. By 1984, the international reference model OSI model, which was not compatible with TCP/IP, had been agreed upon. Many European governments (particularly France, West Germany and the UK) and the United States Department of Commerce mandated compliance with the OSI model, while the US Department of Defense planned to transition from TCP/IP to OSI.
Meanwhile, the development of a complete Internet protocol suite by 1989, and partnerships with the telecommunication and computer industry to incorporate TCP/IP software into various operating systems laid the foundation for the widespread adoption of TCP/IP as a comprehensive protocol suite. While OSI developed its networking standards in the late 1980s, TCP/IP came into widespread use on multi-vendor networks for internetworking and as the core component of the emerging Internet.