From the beginning, we learn about OSI model, which help us to understand the flow of packet from application layer to physical media and then we jump to TCP/IP model, but do we really know which networking model came first: TCP/IP or OSI?
The TCP/IP model, which is realistically the Internet Model, came into existence about 10 years before the OSI model.
Development of the 4-layer TCP/IP model started before work began on the 7-layer OSI Model. As it turned out, TCP/IP had too much momentum to be overtaken by the OSI model or any of the other competing network models. The TCP/IP model is now the dominant protocol suite that is used on today’s Internet. The TCP/IP model is also referred to as the TCP/IP protocol suite, the Internet protocol suite, the TCP/IP stack, and the DoD model.
- ARPANET, the precursor to the Internet, was developed in the late 1960s.
- In May of 1974, Kahn and Cerf published a paper titled “A Protocol for Packet Network Intercommunication,” which described the early ideas of what would become the TCP/IP model.
- In March of 1982, the US Department of Defense declared TCP/IP as the standard for all military computer networking.
- On January 1, 1983 (known as “Flag Day”), the ARPANET switched from the old networking protocol, NCP, to TCP/IP.
In the late 1970s through the 1980s, no networking protocol was dominant. There were many, including IBM SNA, DEC, DECnet, Apple AppleTalk, Banyan Vines, and Novell IPX. Due to many historical circumstances and compared to all the competitors, TCP/IP has gained momentum, and has become the de facto standard in the industry.