The Distributed Interactive Simulation (DIS) Entity Information and Entity Interaction Draft Standard defines a communication protocol to interconnect simulators in a real-time environment. This protocol focuses on the information for describing the state of the simulated entities and their interactions during a battle simulation.

Many of the concepts in the DIS standard are derived from the Simulation Network (SIMNET) project. The SIMNET program has demonstrated the feasibility of interconnecting multiple autonomous simulators, primarily of ground based armor vehicles, via a communication network (LAN/WAN), such that the simulators could interact in real-time. DIS is based upon the foundations of SIMNET and will be enhanced to provide a standard for connecting existing and future simulators. However, a formal description of the DIS standard is yet to be developed, which would, in turn, speed its prototyping, development, and testing processes.

This paper describes the approach taken by the Institute for Simulation and Training (IST) to develop a formal description of DIS, to generate a prototype DIS protocol machine derived directly from the developed DIS formal description, and to test the prototype DIS protocol. IST used an International Organization for Standardization (ISO) standard Formal Description Technique (FDT) called Estelle for the formal specification, and an FDT prototyping tool known as the Portable Estelle Translator - Distributed Implementation Generator (PET-DINGO) to generate a DIS prototype. Furthermore IST developed a procedure to test the generated prototype.

The aim of this work was to develop a formal specification for DIS and to identify possible shortcomings and inconsistencies in the DIS standard. This task identified some areas in the current standard that need to be modified or clarified.