Time Management in Hierarchical Federation Communities

In the High Level Architecture (HLA), systems of systems simulation can be achieved in a distributed manner with federates simulating the subsystems. The system as a whole is then simulated via the collaboration of these federates in a federation. A problem arises when multiple systems are simulated within one federation. A subcomponent (federate) receiving data needs to know if that data was generated by a subcomponent contained within the same overall system. A solution to this problem is to enforce a rule of simulating only one system per federation. Intersystem collaboration is then enabled via inter-federation communication. The systems simulated by federations may themselves be subcomponents of another system. Thus, federations can be grouped to form federation communities that simulate these higher order systems, and collaboration between such systems is enabled via inter-federation community communication. Repeating this process generates a hierarchical simulation architecture and is referred to as a hierarchical federation community. A key challenge in the development of hierarchical federation communities is enabling the HLA services within the architecture. This paper discusses the implementation of the time management services within the hierarchical federation community architecture.