TCP/IP
lorenetworking
Stands for: Transmission Control Protocol / Internet Protocol
The two-protocol architecture, split from a single design in the late 1970s, that became the common language of the internet.
Vint Cerf and Bob Kahn described the idea in 1974 as one 'Transmission Control Program'; by 1978 it was cleaved into TCP for reliable ordered delivery and IP for addressing and routing, so applications that did not need reliability could skip it. The pair were finalized as RFC 793 and RFC 791 in September 1981. On January 1, 1983, ARPANET's flag day, every host was required to switch from the older NCP to TCP/IP at once, the moment usually taken as the birth of the modern internet. Its layered, host-responsible design beat the proprietary networks of IBM, DEC, and Xerox precisely because it was open and royalty-free.
TCP/IP is named after two of its protocols but describes the whole family and, more importantly, an architectural decision: the network should be simple and the endpoints should be smart. Routers forward packets and do not track conversations; reliability, ordering and flow control are the endpoints' problem.
That choice is why the internet scaled. A network core with no per-conversation state can be built by anyone, upgraded independently, and grown without coordination, and a new application needs permission from nobody because the network does not know what applications are. Every competitor that put intelligence in the network offered better guarantees and could not be extended without the operator's cooperation, which turned out to matter more.
The cost is paid at the edges and in the exceptions. Applications must handle loss and reordering themselves or use a protocol that does; the network cannot give real guarantees about latency; and the middleboxes that accumulated in the path anyway, doing exactly the stateful inspection the design excluded, are why protocol evolution is now so difficult. QUIC being built over UDP is the current generation working around the state that the architecture said would not be there.
Also known as: Internet protocol suite, DoD model