Despite years of advances in networking technologies and standards such as Distributed Interactive Simulation (DIS) and High Level Architecture (HLA), the industry still faces interoperability challenges. Over time, legacy simulations can become incompatible with more recently fielded devices. Maintaining forward compatibility between heterogeneous platforms can become problematic, requiring a significant investment of engineering and administrative resources when conducting large distributed exercises between diverse trainers. Maintaining compliance with the latest DIS or HLA standards is one way to plan for change, but these standards have weaknesses that allow disruption of even the best-planned trainer life cycles.

This paper proposes an approach to interoperability and composability centered on an open-source protocol that is, by definition, forward and backward compatible. Because this approach is a cross-platform solution, it can be implemented as a straightforward modification to existing trainer protocols. The proposed approach, initially implemented to allow seamless interoperability for record and playback of communications on distributed exercises, is built from a bottom-up perspective, and directly addresses weaknesses in existing industry standards. By leveraging newer, open-source technologies, this paper presents a solution with an immutable wire encoding, and offers a way to achieve flexibility while maintaining interoperable communication. For a large class of simulations, this approach could dramatically reduce interoperability issues throughout the product life cycle. A specific use-case is demonstrated that illustrates how combining the best elements of DIS and HLA benefits compatibility.