A little history about TCP/IP

TCP/IP protocol is "THE" most popular protocol suite in use in the world (universally-accepted world-wide standard). Its origins can be traced back to 1969 (almost 9 years after born of Unix), a research project funded by US Defense Advanced Research Projects Agency (DARPA). Initially, this ARPAnet was designed to use a number of existing network protocols. However they all had limitations, either in concept or in practical matters sush as capacity. Then the developers at ARPAnet realize that use existing protocols might eventually lead to problems as ARPAnet scaled out. So in 1973, ARPAnet developers decided to write a new protocol. At the early versions of this technology, there was on TCP protocol. The first version of TCP protocol was written in 1973. Then revised and formally documented in RFC 675, Specification of Internet Transmission Control Program, December 1974.

Then testing and development of TCP protocols continued. In March 1977, TCP-v2 was documented. In August 1977, a significant turning point came in TCP/IP’s development. Jon Postel, one of the most important pioneers of the Internet and TCP/IP, pointed out that the version of TCP created in the mid-1970s was trying to do too much:

We are screwing up in our design of internet protocols by violating the principle of layering. Specifically we are trying to use TCP to do two things: serve as a host level end to end protocol, and to serve as an internet packaging and routing protocol. These two things should be provided in a layered and modular way. I suggest that a new distinct internetwork protocol is needed, and that TCP be used strictly as a host level end to end protocol.

-- Jon Postel, IEN 2, 1977

Then the creation of TCP/IP architecture began, the splitting of TCP into TCP at the transport layer and IP at the network layer gives name “TCP/IP”. The process of dividing TCP into two portions began in version 3 of TCP, written in 1978. The first formal standard for the versions of IP and TCP used in modern networks (version 4) were created in 1980. TCP/IP quickly became the standard protocol set for running the ARPAnet. In the 1980s, more and more machines and networks were connected to the evolving ARPAnet using TCP/IP protocols, and the TCP/IP Internet was born.