1984: ARPANET becomes the internet

Originally, the entire ARPANET was managed by the military. But network operators realized that a centralized network would eventually become unmanageable if it continued to grow. They decided that the network should be reorganized as a decentralized "network of networks." Under this scheme, different networks would be controlled by different organizations, but all the networks able to communicate using shared standards, forming a shared "internet." The military asked the computer scientists Robert Kahn and Vint Cerf to develop new networking standards to make this possible. The result was a set of standards known as TCP/IP. These standards specified the basic format of data packets transmitted across the internet. On January 1, 1983, the ARPANET switched to using TCP/IP, marking the birth of the modern internet. The switch to TCP/IP didn't make much difference from a user perspective — applications like email and Telnet worked about the same as they had before. But the new standard paved the way for much faster network growth by lowering the barrier to entry for new networks. One of the first new networks to connect to the new internet was CSNET, which was funded by the National Science Foundation to link computer science departments across the country. This map shows the location of ARPANET and CSNET nodes (labeled "Phonenet"), which after 1983 communicated with each other using TCP/IP. By the time the ARPANET was decommissioned in 1990, it was just one of many networks that comprised the internet. Today, the internet is made up of more than 40,000 different networks. These networks still communicate with each other using the TCP/IP standards Cerf and Kahn developed in the 1970s.