n 1966, was to simply connect the large time-sharing mainframe computers to each other via telephone lines. However, some participants felt that having telephone lines terminating directly on their computers would create unwanted loads. Another idea then surfaced, calling for small independent computers to manage the com- munications links, and to then connect to the large time-sharing machines. This approach allowed the task of running the network to be offloaded from the ARPA- NET computers, while also allowing ARPA to have complete control over the net- work. These smaller computers came to be called interface message processors (IMPs). The initial ARPANET consisted of four IMPs, installed at four universities: Chapter 8 The Internet and IP Infrastructures University of California, Los Angeles; the Stanford Research Institute's Augmenta- tion Research Center; the University of California, Santa Barbara; and the Univer- sity of Utah's Graphics Department. The first ARPANET link was established on October 29, 1969, between the IMP at UCLA and the IMP at Stanford, and the entire four-node network was connected by December 5, 1969. Internet Time Line The following time line shows some of the important dates in the history of the Internet: ARPANET created TCP/IP created TCP/IP required on ARPANET Updated version of TCP/IP introduced NSFNet funded by National Science Foundation (NSF) NSFNet backbone based on T-1 connections ARPANET officially dissolved NSFNet backbone converted from T-1 to T-3 NSFNet dissolved, Internet commercialized Toward the mid-1970s, ARPA was renamed the Defense Advanced Research Projects Agency (DARPA), and while it was working on the distributed, or packet- switched, network, it was also working on local area networks (LANs), paging networks, and satellite networks. DARPA recognized the need for some form of internetworking protocol that would allow open communications between dispar- ate networks. Internet Protocol (IP) was created to support an open-architecture network that could link mul