Running Faster with T3

By Merit/NSFNET Information Services

During the recent National Net '90 conference in Washington, D.C., the NSFNET partnership provided a glimpse into the future of high-speed computer networking.

Prototype equipment transmitted information between Washington D.C. and Ann Arbor, Mich. over a data network running at T3 speed, (45 Mbps), the equivalent of more than 5 million characters per second.

Merit, IBM, and MCI provided direct services and research expertise for the high-speed demonstration at National Net '90.

RISC System/6000* workstations

IBM used several of its recently announced RISC System/6000 workstations equipped with prototype high-speed networking adapters and specially developed packet switching software to connect conference participants in Washington, D.C., with the NSFNET NOC in Ann Arbor.

Clear channel DS3 circuits

The IBM prototype network adapters interfaced directly with MCI's clear channel DS3 circuits connecting the two sites.


The network adapters also connected two RISC System/6000 workstations together locally on a Fiber Distributed Data Interface (FDDI) local area network operating at 100 Mbps.

MCI provided the high-speed fiber optic long-distance telephone circuits, with local support in Washington, D.C. from Industrial Communications Corporation.

MCI applies DS3 expertise

MCI has had previous experience providing DS3 capability directly to supercomputer facilities, and was able to apply the expertise to engineer the circuits for this first packet-switched data transmission demonstration of its type at this high speed.

The demonstration illustrated the technical feasibility of operating a research network like the NSFNET at T3 speed, and showed how such a high speed network would make it possible to effectively use new computing and information resources.

Several applications demonstrated

In the demonstration, two workstations connected over the high-speed T3 link simulated the resources of two scientific collaborators at different locations sharing information.

One application demonstrated the sharing of large image files.

Another illustrated remote access and interactive analysis of an experimental data base representing high-energy particle collision measurements acquired at the European Laboratory for Particle Physics (CERN), on the French-Swiss border near Geneva.

A third application showed an interactive graphic visualization of molecular models synthesized on an IBM 3090 supercomputer located at IBM's Thomas J. Watson Research Center in Yorktown Heights, N.Y.

T3 enables new applications

"The prototype packet switching systems and software we have demonstrated here illustrate the new applications made possible by high-speed networks," said Michael M. Connors, Director of Computing Systems at IBM Research.

Connors continued, "New applications will enable scientists to steer large computations on remote supercomputers and visualize the progress of these simulations across the network in real time."

"A national T3 data network would improve the access to large and expensive shared scientific resources like telescopes, nuclear particle accelerators, wind-tunnels and supercomputers."

Production T3 expected in 1990

It is expected that the NSFNET will begin operational services at the higher speed of 45 Mbps later this year.

In 1987, with a move to T1 service on the NSFNET backbone, bandwidth capacity increased 24-fold over the old 56 kbps network.

When the new T3 services go into effect, the network will have another 28-fold increase which will represent an overall 672-fold increase in capacity.

Crucial to education and industry

"With a T3 network, we can improve our scientific productivity in ways that are currently impossible," said Stephen S. Wolff, a division director at the National Science Foundation.

"This research support is crucial to our educational system and our competitive position as an industrial nation."

High-speed access around the world

MCI Senior Vice President Lawrence J. Bouman remarked, "This demonstration exemplifies the commitment of the NSFNET project partnership to push telecommunications technology to ensure that our research community has high-speed access to information resources across the country and around the world."

More Details on the T3 Demonstration

By Pat Smith, Merit/NSFNET

The T3 link demonstrated at Net '90 was a clear channel end-to-end DS3 (44.736 Mb/sec) bandwidth available for packet communications between Ann Arbor, MI, and Washington, D.C.

In the LaSalle Salon of the L'Enfant Plaza, a UNIX workstation housed in a kiosk connected to a local router which interfaced with an FDDI (Fiber Digital Data Interface) LAN (100 Mb/sec). In turn, the LAN connected to the DS3 link via a RISC System/6000 packet switch.

Interactive graphics

As part of the demonstration, high-resolution, X Windows-based interactive graphics demonstrations were running in Ann Arbor and were viewed on display servers attached to LANs in Washington. Included were two workstations simulating the resources of remote scientific collaborators.

One demonstration application included the sharing of large image data files and a high-energy physics database between the workstations.

Molecular models

Another illustrated remote interactive visualization of molecular models synthesized on a supercomputer.

20 ms roundtrip times

Each application used a portion of available T3/LAN bandwidth and packet switching power. Roundtrip times of 20 ms were achieved on the DS3 channel.

A graphic representation of the configuration is shown below.

Taken from The Link Letter, Vol. 3 No. 1, April 1990.