5.11 - Interoperability Between HLA 1516 Evolved and HLA 4 Federates

Table of Contents

• 5.11.1 HLA 1516 Evolved and HLA 4 Interoperability

5.11.1 HLA 1516 Evolved and HLA 4 Interoperability

MAK ONE products, including VR-Link, support interoperability between HLA 1516 Evolved (IEEE 1516-2010) and HLA 4 (IEEE 1516-2025) federates. Most MAK ONE products are link compatible with the MAK RTI and other RTIs that support these specifications, provided they are built with the same compiler as the MAK ONE product you are using.

To run HLA federates, you must install and configure an RTI on each computer participating in the federation. Federates must be able to locate the RTI libraries (DLLs or shared objects). On Windows, this is typically accomplished by adding the RTI's bin or bin64 directory to the PATH environment variable. On Linux, add the RTI's lib directory to the LD_LIBRARY_PATH environment variable. If you are using the MAK RTI, ensure that you have a valid RTI license for each federate.

All federates in a federation must use the same RTI, configured identically, and must use the same FDD file (for HLA 1516 Evolved and HLA 4). Each federate must be able to locate the FDD file; the simplest approach is to place the file in the directory from which you launch the application. Some RTIs require running an rtiexec process, but only one instance should be run per federation. With the MAK RTI, you may run in lightweight mode without an rtiexec, but advanced features such as Data Distribution Management (DDM), Time Management, or MOM require running rtiexec. Always run different federations on different UDP ports.

Most RTIs rely on an external configuration file (such as rid.mtl for the MAK RTI). Ensure that each federate has access to this configuration file during setup.

When HLA 1516 Evolved and HLA 4 federates interoperate, they must use FDD files that describe the same classes and use VR-Link calls, not direct calls to the RTI. It is important to maintain consistency in FOM format, as HLA 1516 Evolved and HLA 4 use the same root class naming conventions ("HLAObjectRoot" for objects and "HLAinteractionRoot" for interactions). This consistency ensures that federates can discover and publish objects and interactions as intended, avoiding interoperability issues.

• All federates should avoid using features or data types that are not supported across both HLA 1516 Evolved and HLA 4. MOM and Ownership Management are supported, but ensure that your RTI and FOM are configured for compatibility.
• Advanced features such as DDM, Time Management, and MOM require proper RTI configuration and may require running rtiexec.
• All federates must use the same FOM modules and ensure that object and interaction class hierarchies are consistent.

By following these guidelines and requirements, you can achieve reliable interoperability between HLA 1516 Evolved and HLA 4 federates in your MAK ONE-based simulation environment.

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