A Brief History of SIMNET

from 1983 to 1993

(Including a list of the people who were involved in creating it)

What is SIMNET?

SIMNET stands for SIMulator NETworking. Initiated in 1983, it was the first “shared virtual reality” distributed simulation system. It was sponsored by DARPA, the Defense Advanced Research Projects Agency, the Department of Defense’s principal high-risk, high-payoff research and development organization. The SIMNET protocols were the basis for the Distributed Interactive Simulation (DIS) protocols, which were used for the Army’s Close Combat Tactical Trainer (CCTT), Aviation Combined Arms Tactical Trainer (AVCATT), and subsequent procurements. These distributed simulation systems revolutionized how military weapon system development, tactics, and training are conducted.

Why is SIMNET Important?

In 1991, a study of various DARPA initiatives by the Potomac Institute for Policy Studies listed SIMNET as one of six programs that have had the most profound effects on the Department of Defense. To put this in perspective, the other five were the ARPANET (the predecessor of the Internet); the individual computer workstation; phased array radar; the stealth technology used to make aircraft such as the F-117 fighter and the B-2 bomber “invisible” on radar; and ATACMS, the low cost, long-range tactical artillery rocket system used successfully in Desert Storm. Quite a distinguished list!

The principal SIMNET contracters were Bolt, Beranek, and Newman (BBN) of Cambridge, MA, Perceptronics of Woodland Hills, CA, and Delta Graphics of Bellevue WA. Delta Graphics was acquired by BBN in 1986.

The core concept of SIMNET was the networking of multiple simulators, with each simulator providing its own controls, displays, and computational resources. No central control system scheduled events or resolved interactions among the simulation nodes. Instead, each node was autonomous, maintaining authoritative status for one simulated entity (e.g., a tank, helicopter, or missile system) and transmitting messages about the state and actions of its simulated entity to other nodes on a peer-to-peer basis. Each node was also responsible for receiving, interpreting, and responding to messages regarding events that might affect its own entity (e.g., a missile impact, an exploding mine, a collision, etc.) and for reporting any resulting changes in its entity's state (e.g., damaged, destroyed, or unaffected.)

In 1985, the Undersecretary of the Army agreed to redirect funding to DARPA to support SIMNET development, "Because if you can do what you're telling me, it will change the way the Army manages its weapon systems procurement." We did, and it has!

http://simnet-history.org/index.htm
11/28/15
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