Introduction to Internet

What was ARPANET?

ARPANET stands for Advanced Research Projects Agency (ARPA) Network. The network was developed in 1969 by ARPA and funded by the Department of Defense.

The network was chiefly experimental, and was used to research, develop and test networking technologies.

The original network connected four host computers at four separate universities throughout the United States, enabling users to share resources and information

By 1972, there were 37 host computers connected to ARPANET. Also in this year, ARPA's name was changed to DARPA (Defense Advanced Research Projects Agency).

In 1973, ARPANET went beyond the boundaries of the United States by making its first international connections to England and Norway.

One goal of ARPANET was to devise a network that would still be operational if part of the network failed. The research in this area resulted in a set of networking rules, or protocols, called TCP/IP (Transmission Control Protocol/Internet Protocol).

TCP/IP is a set of protocols that govern how data is transmitted across networks. It also enables different types of computer operating systems, such as DOS and UNIX, to share data across a network.

ARPANET functioned as a "backbone" network - allowing smaller local networks to connect to the backbone.

Once these smaller networks were connected to the backbone, they were in effect connected to each other.

In 1983, DARPA decided that TCP/IP would be the standard set of protocols used by computers connecting to ARPANET. This meant that any smaller networks (for example, a university network) that wanted to connect to ARPANET also had to be using TCP/IP.

TCP/IP was available for free and was increasingly used by networks. The spread of TCP/IP helped create the Internet as we know it today - the network of networks that either use the TCP/IP protocols, or can interact with TCP/IP networks.