The Battle Lab Collaborative Simulation Environment (BLCSE) is a complex consortium of military, government civilians, and contractors tasked with integrating simulation technologies and other supporting applications across geographically distributed sites. A key part of this integration is the interoperability of data between simulations. As projects, missions and teams grow in scope greater data interoperability challenges ensue. Therefore, a clear method to configuration manage and control data sets, their changes and related documentation and other files is necessary. Project management alone isn't enough to ensure experiment success, you must have a data and software configuration management process. Configuration Management (CM) is a method that provides structure to a project. Implementing a configuration managed environment forces discipline where otherwise disorder will ensue. An agreement among participants is paramount to success. The mechanism to provide control is a combination of CM and collaborative tools. This paper describes a standard and documented process for data and software configuration management necessary for terrain, entity data, HLA interoperability files and related configurable items. It also describes lessons learned in establishing a vigorous scheme of configuration management during a major distributed event, compares tools and processes available, and concludes with a discussion of configurable items appropriate to a major distributed simulation event. Armed with the right tools and processes, a simulation management team can properly manage data changes so that the federation enables training and experimentation, and the federation users can train to fight and fight to win.