NSFNET -- The National Science Foundation Network

23 Nov 1995


The time of a federally provided general purpose backbone network for the research and science community is coming to a close as of April of 1995. Its roots stem from early ARPA research on packet switching and its development of the TCP/IP protocol suite, which the NSF elected for its NSFNET program in the mid-eighties, at a time of strong tendency towards GOSIP ISO protocols and support for X.25.

Evolving from the Arpanet core model

which centered around a single infrastructure to interconnect campuses, the NSFNET focused on broad operation al interconnection infrastructure which considered regional clients and agency peer networks, each of which would connect to their respective clients.

The TCP/IP selection for the NSFNET resulted in a strong acceptance worldwide in the ten years since the mid-eighties, as the NSFNET creation was the enabler for broad interconnectability in the Internet community. The NSFNET program itself initially came out of the NSF supercomputing center program, with two of the awardees, SDSC and JvNC, having proposed a consortium network. NSF then orchestrated the interconnection of its supercomputing centers via a 56kbps "Fuzzball" based backbone

(already synchronized to radio clocks), to which shortly thereafter regional (or mid-level) networks connected, which used the 56kbps NSFNET backbone as the national interconnection fabric. In July 1988, a 1.544 Mbps

T1 (sorry, photo shows the now empty rack) replacement of the NSFNET backbone operationally started, and was replaced by a 45Mbps T3 backbone

in the early nineties, to meet growing demand patterns. By then the commercialization and privatization of the Internet started to significantly take off, with the NSF getting under increating pressure to move networking activities to the private sector, rather than bulk-providing general networking services by the federal government. This pressure has resulted in a rethinking of the NSFNET architecture, to ensure Internet stability for the time window between government supported services and full privatization of the network.

topology history

The new NSFNET architecture

To address the aforementioned time window, the National Science Foundation created four new projects, three of the infrastructure related, and one of them supporting network research and development activities. Those are:

Network services evolution

In its initial implementation network users typically selected specific services that they explicitly connected to in a one-to-one connection, largely to transfer files, for interactive access to remote machines, and for electronic mail to other users.

This has evolved in the last few years towards a broad "information perimeter" as seen by individual users. The information source is not perceived as specific machines any more, but a horizon consisting of the available information resources, with a one-to-many mapping between a user and information resources.

This has contributed to the notion of an information infrastructure. In the future, even that view will be too limiting, as a many-to-many weave of connectivity is arising, from a mixture of collaboration, information, and generic facility resources environment.


The NSFNET has been shaping the Internet from a federal network research effort, via a federally provided infrastructure, towards a commercialized environment. Some of the next challenges will be in the focus on applications, and how they are provisioned throughout the networked environment, and to support collaboration, information, and facilities resources. Some of the network analysis over the years has shown a dramatic impact of new applications on the IP switching substrate, something that will have to be considered for the overall traffic profiles, as new high end applications demand significant amounts of bandwidth for extensive periods of time.

Some of this is seen already by the increasing use of audio and video applications on the Internet. Alot of areas need further exploration, including:
23 Nov 1995