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'. Fom 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 by using TCP/IP. 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.
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 1981. Lawrence Landweber proposed and managed the creation of CSNET. CSNET was created to connect U.S. research and education institutions who could not connect to ARPANET. The creation of CSNET was supported by the pioneers of ARPANET, such as Vint Cerf. CSNET would connect 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. 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 1980's. 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 decided that NSFNET would be: an all-purpose research network; would connect regional networks to it; and would use TCP/IP. The creation of TCP/IP was funded by DARPA - it was a Department of Defense standard. The NSF elected to support the DARPA Internet organisational infrastructure: which managed the evolution of TCP/IP and Internet information resources.
Jennings was an Irish physicist, and would also inspire the creation of European research networks that used TCP/IP. Jennings devised a three-tier network model for NSFNET:
-Backbone (supercomputer centers) -Tier Two: Regional Networks -Tier Three: Campus Networks
Dennis Jennings blueprint for NSFNET was finalised by 1986, and became operational by late 1986. NSFNET would begin with a backbone of six supercomputer locations, and instead of IMPs (routers used on ARPANET), NSFNET would use 'fuzzball' routers. The NSFNET backbone originally supported a data speed of 56 K-bit/sec.
As more and more regional networks were connected to NSFNET, traffic congestion became an issue, and it became apparent that the NSFNET backbone infrastructure needed to be expanded to support a faster data speed. In 1987, program director Steve Wolff solicited the private sector to upgrade the NSFNET infrastructure.
NSFNET signed a 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. In 1991, NSFNET was 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, which 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. NSFNET had an Acceptable Use Policy, and generally speaking, it did not allow commercial use of the network. By 1991, commercial networks (Internet Service Providers) began to emerge, and these networks were generally connected to the NSFNET backbone; using it's Acceptable Use Policy.
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 used the network hardware designed for NSFNET. Therefore, a situation arised where the network hardware of NSFNET was being used for two purposes: the NSF backbone service and the commercial traffic of ANS CO+RE.
A problem arised 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. This situation created a controversy that led to the 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 owned the physical telecommunications hardware. Network Access Points (NAP) were created to exchange data between these commercial backbone networks.
NSFNET was decommissioned in 1995, but it was instrumental in developing the modern day Internet.