Replication of database servers using the Database State Machine (DBSM) approach has recently been the subject of much attention as it promises both good performance and increased reliability. Ful lling the promise of performance, however, requires that the impact of environment parameters as well as of design and implementation decisions are evaluated in a realistic setting which allows experimentation with con guration and environment parameters. This paper introduces a model that combines simulated network and database engine components with real implementations of termination and communication protocols. This allows us to precisely evaluate the protocols' performance when subjected to a realistic load generated by the simulated database engine. It also allows us to evaluate the impact of the protocol overhead on the overall performance of the database system in several environments. Besides describing the design and validation of the simulation model, results obtained with prototype implementations of the protocols are presented.