The French network that influenced TCP/IP with datagrams and end-to-end design was CYCLADES.
Created in France in the early 1970s under computer scientist Louis Pouzin, CYCLADES explored a different division of responsibilities from ARPANET. Its network switches provided a best-effort datagram service, while hosts at the edges handled reliability, acknowledgments, timeouts, and flow control.
This approach helped establish the end-to-end principle: keep the network’s core relatively simple and let communicating computers provide functions that depend on the complete conversation. CYCLADES also used layered architecture and its CIGALE packet network, whose name came from the French word for “cicada.”
CYCLADES did not become the global Internet, but its design ideas influenced the development of Internet Protocol. It is often confused with Transpac, France’s later X.25-based public packet network. CYCLADES was primarily a research project and was forced to shut down by 1981 after government support was withdrawn.