rconnect four NSF-funded regional supercomputer centers and the National Center for Atmospheric Research (NCAR). This network, dubbed the NSFNET, was originally intended as a backbone for other networks, not as an interconnection mechanism for individual systems. Furthermore, the "Appropriate Use Policy" defined by the NSF limited traffic to non-commercial use. The NSFNET continued to grow and provide connectivity between both NSF-funded and non-NSF regional networks, eventually becoming the backbone that we know today as the Internet. Although early NSFNET applications were largely multiprotocol in nature, TCP/IP was employed for interconnectivity (with the ultimate goal of migration to Open Systems Interconnection). The NSFNET originally comprised 56-kbps links and was completely upgraded to T1 (1.544 Mbps) links in 1989. Migration to a "professionally-managed" network was supervised by a consortium comprising Merit (a Michigan state regional network headquartered at the University of Michigan), IBM, and MCI. Advanced Network & Services, Inc. (ANS), a non-profit company formed by IBM and MCI, was responsible for managing the NSFNET and supervising the transition of the NSFNET backbone to T3 (44.736 Mbps) rates by the end of 1991. During this period of time, the NSF also funded a number of regional Internet service providers (ISPs) to provide local connection points for educational institutions and NSF-funded sites. In 1993, the NSF decided that it did not want to be in the business of running and funding networks, but wanted instead to go back to the funding of research in the areas of supercomputing and high-speed communications. In addition, there was increased pressure to commercialize the Internet; in 1989, a trial gateway connected MCI, CompuServe, and Internet mail services, and commercial users were now finding out about all of the capabilities of the Internet that once belonged exclusively to academic and hard-core users! In 1...
