Simulation cloning is designed to satisfy the requirement of examining alternative scenarios concurrently. This paper discusses the issues involved in cloning distributed simulations based on the High Level Architecture (HLA) as well as proposing tentative solutions. Alternative solutions are compared from both the qualitative and quantitative point of view. In terms of federation organization, candidate solutions can be classified into the single-federation and the multiple- federation categories. In order to guarantee the correctness and optimize the performance of the whole cloning-enabled distributed simulation, the single- federation solution requires an additional mechanism to isolate the interactions amongst alternative executions. Data Distribution Management (DDM) is one of the candidate approaches. To measure the trade-off between complexity and efficiency, we introduce a series of experiments to benchmark various solutions at the RTI level. The benchmark results indicate that the single- federation solution provides encouraging performance when using DDM.