The MeshRouter system provides a general framework for scalable, interestlimited communications among processors in largescale distributed simulations, such as the SAF family. The architecture was initially developed and implemented within the specific context of the ModSAF application and has recently been implemented in the JSAF/JUO application, using standard RTIs communications primitives. This work provides a more general analysis of the MeshRouter system, clarifying the applicationspecific requirements for use of the communications framework and presenting a number of communications performance studies (total message throughput) for a system of simple federates using RTIs communications. The overall MeshRouter architecture is reviewed, emphasizing the applicationindependent overall structure and the modest additional work needed to adapt the framework to the specific case of RTIs communications.

The RTIs MeshRouter is then compared with a treebased communications built from standard RTIs routers, using pair wise message exchanges among simple federates. It is shown that MeshRouter performance is compatible with tree performance for trivial (e.g., nearestneighbor) communications, and, more importantly, the aggregate bandwidth supported by the MeshRouter is substantially higher for nontrivial communications patterns, as would be expected in any realistic simulation environment. The communications performance studies are presented versus a number of relevant variables, including message size, total number of participating federates, and nominal length of the communications path. Extensions of the basic mesh topology used within the performance study are noted, including both modifications to support fault tolerance and a simple Tree/Mesh hybrid that could be easily implemented within the context of ongoing JSAF/JUO operations. Finally, the extensions of the existing MeshRouter software needed to support the OneSAF/RTIN application are discussed.