Foreword?This standard is the capstone document for a family of related standards that together describe a unified approach to constructing interoperable simulation systems.The HLA provides a general framework within which simulation developers can structure and describe their simulation applications. Flexibility is the aim of the HLA. In particular@ the HLA addresses two key issues: promoting interoperability between simulations and aiding the reuse of models in different contexts. Two main components are described within the set of products forming the HLA. The first is the Object Model Template (OMT)@ which forms a documentation standard describing the data used by a particular model@ a necessary basis for reuse. The second component@ the Federate Interface Specification@ describes a generic communications interface that allows simulation models to be connected and coordinated@ thus@ addressing interoperability. Although the HLA is an architecture@ not software@ use of runtime infrastructure (RTI) software is required to support operations of a federation execution. The RTI software provides a set of services@ as defined by the Federate Interface Specification@ used by federates to coordinate operations and data exchange during a runtime execution.Simulations are necessarily abstractions of the real world@ and no one simulation design can meet the functional needs of the entire modeling and simulation community. However@ in defining an overriding architecture@ generic issues can be addressed. When doing so@ it is essential that such an architecture encompass both differing computing environments and differing classes of simulations.This standard document of the Framework and Rules is intended to provide some of the general philosophy behind the HLA@ including guidance about how to design@ use@ and adhere to the HLA vision. Scope?This document provides an overview of the High Level Architecture (HLA)@ defines a family of related HLA documents@ and defines the principles of HLA in terms of responsibilities that federates (simulations@ supporting utilities@ or interfaces to live systems) and federations (sets of federates working together) must uphold.