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
NSFNET evolves from ARPANET and CSNET
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
NSFNET is planned
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:
- Princeton University (John von Neumann Center)
- University of California, San Diego (Supercomputer Center)
- University of Illinois (National Center for Supercomputing
- Cornell University (Cornell Theory Center)
- University of Pittsburgh (Pittsburgh Supercomputing Center
- National Center for Atmospheric Research (NCAR)
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:
- Tier One: Backbone (supercomputer centers)
- Tier Two: Regional Networks
- Tier Three: Campus Networks
NSFNET is operational
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
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:
- BARRNet (Bay Area Regional Research Network)
- ESnet (Energy Sciences Network)
- MichNet (Michigan Network)
- MIDnet (Midwest Network)
- MILNET (Military Network)
- NSN (NASA Science Network)
- NorthWestNet (North West Network)
- NYSERNet (New York State Education and Research Network)
- SESQUINET (Sesquicentennial Network)
- SURAnet (South Eastern Universities Research Association Network)
- Westnet (West State Network)
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
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 and commercialisation
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
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:
- CERFnet (California Education and Research Federation Network)
- PSInet (Northern Virginia Network)
- UUnet (UUNET Communications Services)
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.