NSFNET was a computer network funded by the National Science Foundation - an agency of the government United States of America. NSFNET stands for the 'National Science Foundation Network'. From 1987-1992, NSFNET was viewed as being the backbone network of the Internet. The Internet is a term, coined by C.Sunshine, V.Cerf and Y.Dalal, to describe a system of computer networks that interconnect using the TCP/IP software. In 1987, when NSFNET had become operational, Ed Krol released a Hitchhiker's Guide - one of the first guides to the Internet - to explain the basic concepts of NSFNET and this document has been published in RFC 1118.
ARPANET was the first computer network in the United States to connect research and education institutions. ARPANET pioneered packet switching, and the TCP/IP protocol suite was designed by Vint Cerf and Bob Kahn for ARPANET. Due to the Mansfield Amendment of 1973, the Department of Defense (ARPA was a US defense agency) was directed to no longer fund the development of science projects. ARPANET was split into a military and a research network. The research network of ARPANET was planned to be slowly phased out from 1975 onwards.
Due to a lack of funding to expand and develop ARPANET, the National Science Foundation funded the creation of CSNET (Computer Science Network). In 1979, Lawrence Landweber, Professor Emeritus of Computer Science at the University of Wisconsin, proposed the creation of CSNET - with support from Dave Crocker, Vint Cerf and DARPA - to connect U.S. universities, industries and government computer research groups. His proposal received $5 million in funding in January 1980. The team created to build CSNET included: L. Landweber, B. Kern, P. Denning, and T. Hearn. CSNET was created to connect U.S. research and education institutions who could not connect to ARPANET.
CSNET initially connected the following U.S. institutions (amongst others): University of Minnesota, University of Wisconsin, University of Oklahoma, University of California-Berkeley, and Yale University. CSNET was funded from 1981 to 1984 by the National Science Foundation; by 1984 the network had expanded to over 150 universities. CSNET would continue to operate until 1991. Due to the success of CSNET - and a lack of interest from the Department of Defense to expand ARPANET - the National Science Foundation planned the creation of a new expanded network in 1984: NSFNET. NSFNET would be based upon the software systems (protocols) of ARPANET, and the computer scientists who pioneered the protocols of ARPANET would continue to develop them for NSFNET and other TCP/IP computer networks.
When NSFNET was launched in 1985, ARPANET was slowly decommissioned from 1985-1989.
The National Science Foundation funded a range of computer science projects: chief amongst them was the creation of a supercomputing program in the early 1980s. Science projects had increasingly become reliant on computers, and relied on powerful computing power. Part of the NSF's supercomputing program was to connect the supercomputers together to form a computer network. This network would become NSFNET, and it was envisaged that data could travel up to twenty-five times faster on NSFNET than it could on CSNET: due to the power of the supercomputers. By 1984, the NSF had funded the construction of supercomputers at the following locations:
In 1985, the NSF hired Dennis Jennings to manage the creation of NSFNET. Jennings was an Irish physicist and computer networking pioneer who was an active participant in the creation of the TERENA European research network. Jennings decided that NSFNET would: function as an all-purpose research network; it would act as a backbone network that would facilitate the connection of regional networks to it; and it would use the TCP/IP protocol suite implemented on MILNET and ARPANET. The creation of TCP/IP was funded by DARPA - it became a Department of Defense standard, and the NSF elected to support the DARPA Internet organisational infrastructure - such as the IAB - that managed the development of TCP/IP and namespace resources. During the 1980's there was a competition between the IP and OSI networking models - referred to as the protocol war - and it was feasible that Jennings could have picked to use the OSI instead of IP for NSFNET. This decision was crucial for the development of IP networks, that would eventually interconnect to become the modern Internet in the early 1990's. The infrastructure plan, outlined by Jennings, for NSFNET was as follows: -Backbone (supercomputer centers); -Tier Two: Regional Networks; -Tier Three: Campus Networks.
NSFNET was operational by late 1986. The team that built NSFNET included: members of NCSA including Ed Krol and C. Kline; members of CUTC including A. Brown and S. Brim; members of the University of Delaware including D. Farber and D. Mills; and H.W. Braun of Merit. NSFNET was built upon a backbone of six supercomputer locations, operating at a data speed of 56 K-bit/sec, with each supercomputer connected to a newly designed 'fuzzball' router - the fuzzball tested new routing protocols like NTP. The first problem that arrived with the new NSFNET backbone was its data speed: as more regional networks were connected, traffic congestion became an issue, and it became apparent that the NSFNET backbone infrastructure needed to be upgraded to support a faster data speed. In 1987, program director Steve Wolff solicited the private sector to upgrade the NSFNET infrastructure. In 1987, NSFNET signed a $39 million five-year cooperative agreement with Merit, IBM, and MCI to upgrade the NSFNET backbone. In 1988, the NSFNET backbone was upgraded to a 1.5 Mbit/s T1 network that featured thirteen nodes, and by 1991, NSFNET had been upgraded to a 45 Mbit/s T3 network that featured sixteen nodes. IBM focused on upgrading the packet switching hardware and software of NSFNET, and MCI upgraded the transmission circuits.
From 1987-1991, the NSFNET backbone was connected to a variety of regional and federal computer networks. To name but a few:
Most of the regional networks listed above were connected to smaller (campus) networks, which numbered into the thousands. NSFNET was interconnected to other U.S. federal networks when the Federal Internet Exchange (FIX) was established in 1989. Therefore, for the first time, a 'network of networks' was formed, that would closely resemble the modern Internet. The NSFNET backbone was at the 'heart' of this configuration, and became known as the Internet's backbone. By 1992, over 4,000 networks in the United States were connected to the NSFNET backbone, and over 2000 international networks were connected to the NSFNET backbone.
NSFNET was designed to foster communication between educational and research institutions in the United States of America. Therefore, the NSF, generally speaking, did not allow commercial use of its backbone network. By 1991, commercial networks (Internet Service Providers) were being founded to provide access, to IP networks, to the general public. NSFNET created an 'Acceptable Use Policy' to allow these networks to connect to the NSFNET backbone. The problem was that the 'Acceptable Use Policy' of NSFNET did not allow unrestricted commercial use. In 1991, three commercial computer networks decided to create the Commercial Internet Exchange (CIX) : CIX would allow commercial traffic to be exchanged between these networks. The three networks were:
At the same time, Merit, IBM, and MCI created a new commercial Internet Service Provider, named ANS CO+RE. ANS CO+RE, that used the network hardware designed for NSFNET. Therefore, a situation arose where the network hardware of NSFNET was being used for two purposes: the NSF backbone service and the commercial traffic of ANS CO+RE. Another problem arose when ANS CO+RE refused to interconnect their network with the Commercial Internet Exchange (CIX): which created a perceived monopoly of the network hardware of the NSFNET backbone. While a compromise was eventually reached between ANS CO+RE and CIX, the controversy created by it would eventually lead to a reconfiguration of the network architecture of the Internet's backbone. Instead of a centralised Internet backbone that was federally funded, it was decided that the backbone of the Internet would be comprised of commercial networks - typically large telecom companies - who would charge users to access their network. The transition from the NSFNET backbone to a privatised commercial backbone was a drawn out process, involving Network Access Points (NAP), that exchanged data between these commercial backbone networks. NAPs were the forerunner of Internet Exchange Points; such as The London Internet Exchange (LINX). The NSFNET backbone was officially decommissioned on the 30th of April 1995. NSFNET was instrumental in the development of the modern Internet.