“A Protocol for Packet Network Intercommunication,” by Vinton G. Cerf and Robert E. Kahn, appeared in the IEEE Transactions on Communications, volume COM-22, number 5, in May 1974, on pages 637 to 648. It is the paper that introduced the Transmission Control Protocol and laid out the architecture for joining many separate packet-switched networks into a single internetwork. It is one of the founding documents of the internet.
The paper’s central problem is heterogeneity: by the early 1970s there were several incompatible packet networks, including the ARPANET, packet radio networks, and satellite networks, each with its own addressing, packet sizes, and conventions. Cerf and Kahn proposed a way to interconnect them without forcing any network to change its internal design. Their answer was a layer of devices they called gateways, sitting between networks, that would route packets from one network to another and handle the differences between them, including breaking packets into smaller pieces when a network required it.
To make this work, they defined a common transport protocol, TCP, that ran in the hosts at the edges of the networks rather than in the networks themselves. TCP would provide reliable, ordered delivery of a stream of bytes between two processes, recovering from lost or duplicated packets, while the networks in the middle only had to make a best effort to carry packets. This division of labor, intelligent endpoints over a simple network, anticipated the end-to-end principle and became the defining shape of the internet.
The protocol described in the paper was at first a single combined design; it was later split into TCP and IP, the reliable transport layer and the connectionless internet layer. The first detailed written specification followed in RFC 675 (December 1974), and the design was refined over the next several years into the 1981 specifications RFC 791 and RFC 793. For this work Cerf and Kahn received the 2004 ACM A.M. Turing Award.