A full-scale simulation is a comprehensive crisis exercise that plays through an emergency scenario under conditions as realistic as possible. Unlike a tabletop exercise, actual systems, communication channels, and processes are activated. Participants act in their real roles under time pressure. In an ISMS, a full-scale simulation tests whether emergency and business continuity plans actually work in practice. The effort is substantial, but the results are the most meaningful. An annual full-scale simulation is considered best practice.