Implementation issues for shared state in HLA-based distributed simulation

The problem of shared state is well known to the parallel and distributed simulation research community. In this paper, we revisit the problem of shared state in the context of a High Level Architecture based distributed simulation. A middleware approach is proposed to solve this problem within the framework of the High Level Architecture Runtime Infrastructure. Four solutions to this problem are implemented in the middleware using receive-order messages. We will discuss the implementation issues of these four solutions in the middleware. Experimental results comparing the performance of these four solutions against a simple request-reply approach using time-stamp-order messages are also presented.