In the sixties, researchers of the Advanced Research Projects Agency (ARPA) in the U.S. were requested by the Department of Defense (DoD) to develop a system for saving information military important in case of a war. The result of their work was an electronic network the ARPAnet. Military information was stored on all computers that were part of the network. The computers were installed in different places far away from each other and information was exchanged in several different ways. New or updated data on the computers was to be synchronized in a very short time so that in case of the destruction of one or more computers, no data would be lost.

In the 1970s, the DoD allowed nonmilitary research institutes to access the ARPAnet. The researchers were more interested in the connected computers than in synchronizing data. They used it for exchanging information, and students at these institutes used a part of the network as a blackboard for communicating with each other this was the beginning of Usenet.

In the 1980s, the military and civil parts of the ARPAnet were divided. In other countries, similar activities led to national networks. At the end of the 1980s, most of the national networks became connected to each other. The Internet was born.

It was necessary to have a standardized way to communicate over different types of networks and with different kinds of computers. So TCP/Internet Protocol (TCP/IP), which was developed by ARPA, became a worldwide standard.

TCP/IP is...