From Overview of HLA and RTI DMSO Standards ARL Training Session IMT Dec 4 97 -- Dec 4 97. byGeoffrey Fox but selected by W. Furmanski from DMSO
RTI Executive, FEDEX's and Federates are arranged hierarchically where you can think of a federate as a single process (as far as HLA is concerned) running in a single computer.
This would not be true for linking complex legacy systems where a federate is itself a distributed simulation