Federates shall have an HLA simulation object model (SOM), documented in accordance with the HLA object model template (OMT). Federates shall be able to update and/or reflect any attributes of objects in their SOM and send and/or receive SOM object interactions externally, as specified in their SOM. Federates shall be able to transfer and/or accept ownership of an attribute dynamically during a federation execution, as specified in their SOM. Federates shall be able to vary the conditions under which they provide updates of attributes of objects, as specified in their SOM. Federates shall be able to manage local time in a way that will allow them to coordinate data exchange with other members of a federation. HLA Evolved The IEEE 1516 standard has been revised under the SISO HLA-Evolved Product Development Group and was approved 25-Mar-2010 by the IEEE Standards Activities Board. The revised IEEE 1516–2010 standard includes current DoD standard interpretations and the EDLC API, an extended version of the SISO DLC API. Other major improvements include: Extended XML support for FOM/SOM, such as Schemas and extensibility Fault tolerance support services Web Services (WSDL) support/API Modular FOMs Update rate reduction Encoding helpers Extended support for additional transportation (such as QoS, IPv6,...) Standardized time representations Federation Conformance In order to ensure the proper interaction between simulations, a way of testing federate conformance is defined. This involves ensuring that every class and interaction listed in the SOM for a particular federate is used according to the usage described, "PublishSubscribe", "Publish", "Subscribe" or "None". STANAG 4603 HLA (in both the current IEEE 1516 version and its ancestor "1.3" version) is the subject of the NATO standardization agreement (STANAG 4603) for modeling and simulation: Modeling And Simulation Architecture Standards For Technical Interoperability: High Level Architecture (HLA). Related standards Base Object Model The Base Object Model (BOM), SISO-STD-003-2006 is a related standard by SISO to provide better reuse and composability for HLA simulations. It provides a way to specify conceptual models and how to map them to an HLA FOM. Alternatives In regards to the Distributed Modeling and Simulation (DM&S) industry the most often used alternative to the HLA, for real-time simulation of military platforms, is Distributed Interactive Simulation (DIS), IEEE 1278.1-2012, a simulation protocol. Most HLA RTI vendors also feature DIS in their products. As for middleware applications that most closely match HLA features, such as the publish and subscribe feature (P&S) see