Defense Simulation Internet

The DSI evolved from DARPA's earlier Terrestrial Wideband Network, which could provide the realtime multicast with bandwidth guarantees that are essential to distributed interactive simulations via the Internet Stream Protocol (ST-II).

A Defense Science Board study in 1993 highlighted the importance of these capabilities in simulations, and by late 1994, the DSI connected about 100 local area networks at sites around the world.

Phase I of the DSI was implemented by BBN T/20 routers running the Internet Stream Protocol.

Phase II, completed in October 1997, was a reimplementation using Cisco 7500 routers running the Resource Reservation Protocol (RSVP) over ATM permanent virtual circuits.

The Phase II topology was a mesh of 7 backbone nodes, with 46 tail circuits running to the other DSI sites as of April 1998.