Distributed Interactive Simulation
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Distributed Interactive Simulation (DIS) is an open standard for conducting real-time platform-level wargaming across multiple host computers and is used worldwide especially by military organizations but also by other agencies such as those involved in space exploration and medicine.
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[edit] History
The standard was developed over a series of "DIS Workshops" at the Interactive Networked Simulation for Training symposium, held by the University of Central Florida's Institute for Simulation and Training (IST). The standard itself is very closely patterned after the original SIMNET distributed interactive simulation protocol, developed by Bolt, Beranek and Newman for Defense Advanced Research Project Agency in the early through late 1980's. BBN introduced the critical concept of dead reckoning to efficiently transmit the state of battle field entities, as well implementing DARPA's vision of simulations involving inexpensive general purpose computers (vs. 6DOF motion platforms and/or supercomputers), hundreds of online players (not just the 'onesies and twosies' which had been done before), wherein the realism and training value came not from high-fidelity simulation of vehicle dynamics but by the real time play with lots of intelligent allies and lots of intelligent opponents.
In the early 1990's, IST was contracted by the United States Defense Advanced Research Project Agency to undertake research in support of the US Army Simulator Network (SimNet) program. Funding and research interest for DIS standards development decreased following the proposal and promulgation of its successor, the High Level Architecture (simulation) (HLA, initially entitled DIS++), in 1996. HLA was produced by the merger of the DIS protocol with the Aggregate Level Simulation Protocol (ALSP) designed by MITRE.
There was a NATO standardisation agreement (STANAG 4482, Standardised Information Technology Protocols for Distributed Interactive Simulation (DIS), adopted in 1995) on DIS for modelling and simulation interoperability, but this was also abandoned in favour of HLA as early as 1998. The first draft HLA STANAG ran afoul of administrative procedures when it changed sponsors within NATO, which forced the process to start all over again at square one. In 2006 the HLA STANAG (4603) were finished and ratified by several NATO nations.
[edit] The DIS family of standards
DIS is defined under IEEE Standard 1278:
- IEEE 1278-1993 - Standard for Distributed Interactive Simulation - Application protocols
- IEEE 1278.1-1995 - Standard for Distributed Interactive Simulation - Application protocols
- IEEE 1278.1-1995 - Standard for Distributed Interactive Simulation - Application protocols - Errata (May 1998)
- IEEE 1278.1A-1998 - Standard for Distributed Interactive Simulation - Application protocols
- IEEE-1278.2-1995 - Standard for Distributed Interactive Simulation - Communication Services and Profiles
- IEEE 1278.3-1996 - Recommended Practice for Distributed Interactive Simulation - Exercise Management and Feedback
- IEEE 1278.4-1997 - Recommended Practice for Distributed Interactive - Verification Validation & Accreditation
- IEEE 1278.5-XXXX - Fidelity Description Requirements (never published)
In addition to the IEEE standards, the Simulation Interoperability Standards Organization (SISO) maintains and publishes an enumerations and bit encoded fields document yearly. This document is referenced by the IEEE standards and used by DIS and HLA federations. Both a PDF and XML version are available.
[edit] Current status
SISO, a sponsor committee of the IEEE, promulgates improvements in DIS. Contrary to some people's opinions (and desires), DIS is not dead, but is still in use by many groups.
Major changes are already in the draft update to IEEE 1278.1 to make DIS more extensible and efficient and to support the simulation of new real world capabilities. Click on the DIS Product Development Group link under External Links for more information.
Download a free copy of the DIS Find-It-Fast Guide that has links to All Things DIS!
Find out about the availability of open source DIS XML and DIS X3D.
[edit] Application protocol
Simulation state information is encoded in formatted messages, known as Protocol Data Units (PDUs) and exchanged between hosts using existing transport layer protocols, though normally broadcast User Datagram Protocol is used. There are several versions of the DIS application protocol, not only including the formal standards, but also drafts submitted during the standards balloting process.
- Version 1 - Standard for Distributed Interactive Simulation - Application Protocols, Version 1.0 Draft (1992)
- Version 2 - IEEE 1278-1993
- Version 3 - Standard for Distributed Interactive Simulation - Application Protocols, Version 2.0 Third Draft (May 1993)
- Version 4 - Standard for Distributed Interactive Simulation - Application Protocols, Version 2.0 Fourth Draft (March 1994)
- Version 5 - IEEE 1278.1-1995
- Version 6 - IEEE 1278.1-1995 and IEEE 1278.1A-1998
- Version 7 - IEEE 1278.1-200X (in preparation - scheduled for completion and IEEE balloting in Summer 2007. See External Link - DIS Product Development Group.)
[edit] Protocol data units
The current version of the DIS application protocol defines 67 different PDU types, arranged into 12 families. Frequently used PDU types are listed below for each family.
- Entity information/interaction family - Entity State, Collision, Collision-Elastic, Entity State Update
- Warfare family - Fire, Detonation
- Logistics family - Service Request, Resupply Offer, Resupply Received, Resupply Cancel, Repair Complete, Repair Response
- Simulation management family - Start/Resume, Stop/Freeze, Acknowledge
- Distributed emission regeneration family - Designator, Electromagnetic Emission, IFF/ATC/NAVAIDS, Underwater Acoustic, Supplemental Emission/Entity State (SEES)
- Radio communications family - Transmitter, Signal, Receiver, Intercom Signal, Intercom Control
- Entity management family
- Minefield family
- Synthetic environment family
- Simulation management with reliability family
- Live entity family
- Non-real time family
