Abstract: The fast growth of data intensive applications has caused a change in the traditional storage model. The server-to-disk approach, usually implemented with SCSI buses, is being replaced by storage area networks (SANs), which enable storage to be externalized from servers, thus allowing storage devices to be shared among multiple servers. A SAN is a separate network for storage, isolated from the messaging network and optimized for the movement of data between servers and storage devices. Nowadays, most of current SANs use Fibre Channel as the technology to move data between servers and storage devices. In order to design and evaluate the performance of these systems it is necessary to have adequate tools. Usually, performance evaluation may be based on analytical modeling or simulation. Each of them differs in their scope and applicability. However, the simulation modeling technique offers more freedom, flexibility, and accuracy than analytical methods. Thus, when evaluating the performance of SANs, simulation modeling should be used. In this paper we present the main capabilities of a simulator for Fibre Channel SANs, focusing on its input parameters and output variables. We also show several simple examples of performance measurements that can be obtained using this tool.