The Time Story logoThe Time StorySign in
Back to Standardisation Of Tcp Ip And The Birth Of The Internet 4m0ca
Standardisation of TCP/IP and the Birth of the Internet

Moment 3 of 12

TCP split into Transmission Control Protocol and Internet Protocol

January 1, 1978

In early 1978, computer scientists led by Vint Cerf, Jon Postel, and Danny Cohen finalized the architectural decision to split the monolithic Transmission Control Program into two distinct functional layers: the Transmission Control Protocol (TCP) and the Internet Protocol (IP).

The original TCP design handled both host-to-host reliability and end-to-end network routing within a single protocol layer. However, emerging applications like real-time packet voice communication suffered from severe latency caused by TCP's strict requirement to retransmit lost packets and reorder incoming streams.

By decoupling network routing from packet delivery guarantees, IP was established as a simple, stateless layer responsible solely for addressing and routing individual datagrams across networks. TCP remained as a higher layer managing connection reliability. This modular architecture allowed the development of unacknowledged transport protocols like UDP, enabling low-latency multimedia streaming alongside reliable byte transfers.

Why it matters

Decoupling IP from TCP established the modular, layered architecture of the modern Internet protocol suite. It allowed the Internet to support diverse transport protocols tailored for different needs—such as TCP for error-free file transfers and UDP for real-time video and audio streaming—on top of a universal network layer.

Interesting fact

The primary push to split TCP came from early experiments with real-time internet telephony, because TCP's retransmission of dropped packets caused intolerable audio delays during live voice calls.

People

  • Vint CerfDARPA Program Manager
  • Jon PostelRFC Editor at USC Information Sciences Institute
  • Danny CohenUSC/ISI Computer Scientist and Real-Time Packet Voice pioneer
  • David P. ReedMIT Computer Scientist and designer of UDP datagram concepts

Quotes

"We needed a simple datagram service that didn't guarantee delivery, so real-time voice wouldn't be delayed by retransmissions."
— Danny Cohen

Location

USC Information Sciences Institute · Marina del Rey · United States

Open in Google Maps

Watch

References