vBNS and the early research networks, 1995–2007

Updated November 2026

In April 1995, as the NSFNET backbone was handed over to commercial providers, the National Science Foundation and MCI launched the vBNS, a separate high-speed network for research. Over five years it grew from 155 Mbit/s to 2.4 Gbit/s and connected about a hundred universities and research institutions, and it served as the first backbone for Internet2. Many of the performance tools still in use today, including iperf, were built to get the most out of it.

Before the vBNS: NSFNET

NSF launched NSFNET in 1986 to connect academic researchers to its new supercomputer centers. It grew from around 2,000 connected computers in 1986 to more than 2 million by 1993 and became, in practice, the backbone of the US Internet. As commercial Internet services grew in the early 1990s, NSF shut NSFNET down in 1995 and the backbone role passed to commercial operators.

That left researchers with a problem. Networks then connected to the Internet topped out at 45 Mbit/s, and scientists moving large data sets between supercomputers needed far more.

The vBNS

The very-high-speed Backbone Network Service (vBNS) was announced in April 1995. MCI built and ran it under a five-year cooperative agreement with NSF, reported at the time as worth $50 million: NSF paid MCI $10 million a year from April 1, 1995 to March 31, 2000. Key points:

Purpose: high-speed links between the NSF supercomputer centers and to NSF-specified Network Access Points, the exchange points where networks met. It was for research that needed high bandwidth, not general Internet traffic.
First sites: the five supercomputing centers: Cornell Theory Center, NCAR, NCSA, the Pittsburgh Supercomputing Center and SDSC.
Network Access Points: San Francisco (Pacific Bell), Chicago (Ameritech), New York (Sprint) and Washington, DC (MFS).
Speed: at least 155 Mbit/s at launch, more than three times the fastest commercial links (155 ÷ 45 ≈ 3.4).

Growth

vBNS milestones
Date	Milestone
April 1995	Launch, 155 Mbit/s minimum, five supercomputing centers
January 1998	Running at 622 Mbit/s; 63 universities approved for connections, about 100 planned; 2.4 Gbit/s expected by 2000
April 2000	Speeds up to 2.4 Gbit/s, most schools connected at about 620 Mbit/s; 101 institutions connected
March 2000 to March 2003	No-cost extension: MCI WorldCom keeps the network running at no cost to NSF; universities pay full cost once their grants end

Universities got onto the vBNS through NSF’s High Performance Connections awards, which paid part of the cost of a campus link; by April 2000 NSF had made such awards to 177 universities. The vBNS was also part of the federal Next Generation Internet initiative.

Where NLANR fitted in

A fast backbone does not guarantee fast applications: end-to-end speed also depends on host settings such as TCP window sizes and on the campus networks at each end. NLANR’s job was to help close that gap: its engineers helped campuses connect, its applications team helped users tune their software and wrote tools such as iperf to measure what the path could really deliver, and its measurement team monitored the vBNS and the networks around it. The same problems, and the same fixes, still apply on today’s 100 Gbit/s networks; see TCP tuning and iperf. More detail is on the NLANR history page.

Internet2 and Abilene

In 1996, leaders from 34 universities met in Chicago and started the project that became Internet2, a consortium of US universities building advanced networking for research and education. The vBNS served as its first backbone, and member universities began connecting through regional aggregation points called gigaPoPs in 1997.

Internet2 then built its own backbone, Abilene, introduced at a White House event in 1998. By May 1999 it had begun nationwide operations at 2.4 Gbit/s, serving 37 universities, with equipment and services from Qwest, Cisco Systems and Nortel Networks and with Indiana University as a partner. In 2007 Internet2 moved to a new 100 Gbit/s network built with Level 3 Communications, and traffic was moved off Abilene by September 2007.

Research networks today

The model the vBNS pioneered, a dedicated high-capacity network for research and education, is now standard around the world.

Internet2, the nonprofit founded in 1996 (formally UCAID), runs the US research and education backbone and is working toward native 800 Gbit/s backbone capacity.
ESnet, funded by the US Department of Energy’s Office of Science and run by Lawrence Berkeley National Laboratory, connects the DOE national laboratories with 400 Gbit/s to 1.6 Tbit/s links and close to 85 Tbit/s of total capacity. ESnet also develops iperf3.
National and regional research networks in other countries, such as Europe’s GÉANT and Brazil’s RNP, work with ESnet and Internet2 on shared measurement tools such as perfSONAR.