The encyclopedia · Software & IT · Technical decision · 1973–1983
TCP/IP beat OSI by being open, free and shipped inside every Unix.
DARPA published TCP/IP as open, royalty-free, vendor-neutral specs and gave away a reference implementation, so the world adopted it without asking.
Vint Cerf · Bob Kahn · DARPA
the move
Through the 1970s, IBM, DEC, AT&T and Xerox built proprietary, mutually incompatible networks, and ARPANET's own protocols struggled to span radio, satellite and local links. Vint Cerf and Bob Kahn designed TCP/IP as a way to join many different kinds of network into one.
DARPA published the finalized TCP/IP specifications in September 1981 as freely available RFCs, and the suite was fundamentally non-proprietary, royalty-free and vendor-neutral: any computer could speak it so long as it implemented the software.
That openness was matched with implementation. The suite was distributed with BSD Unix, so a tested, working stack arrived inside the operating system that was sweeping through computing. The definition was public and the code was free, so there was no permission or licensing hurdle between anyone and the network.
When the United States moved ARPANET to TCP/IP on 1 January 1983, and as the OSI stack stayed bogged down in committees, the open suite became the foundation of the internet that followed.
why it works
- Open, royalty-free specifications removed any licensing or ownership reason to refuse the protocol.
- A free reference implementation inside BSD Unix meant the full stack arrived with the OS everyone was adopting.
- Being vendor-neutral let rivals both use it, which is what a common standard has to permit.
- Working, tested code beat a theoretically cleaner OSI that moved too slowly through committees.
what transfers
A protocol that is open and free beats a better-designed but proprietary or slow-moving alternative, because adoption is a permission problem, not a quality problem.
what came after
TCP/IP became the protocol of the internet, and the open-specification, free-implementation model it pioneered became the playbook for the standards bodies that followed, while the more elaborate OSI stack faded despite its richer design.
references
- The Foundation of the Internet: TCP/IP Turns 40
- RFC 791: Internet Protocol (DARPA Internet Program Protocol Specification)
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