OSPF and IS-IS: Choosing an IGP for Large-Scale Networks

1.5. Routing in the ARPANET

By the time of the NCP-to-TCP/IP transition at the beginning of 1983, two communities were using the ARPANET: military operations and university/corporate researchers. Particularly in the second community, a tremendous number of graduate students was learning to appreciate and use the network in ways that would quickly influence the business community. They were also using the network for some distinctly nonresearch activities such as gaming. As a result of this large and growing user population, the Department of Defense became concerned about security, and decided to move their nodes to a separate network called the MILNET. But they wanted to continue to have access to the ARPANET nodes, so the two networks remained ...