As is true for most new technologies, the learning curve for SANs can be challenging. There are new concepts, terms and products to figure out. One of the areas of confusion for SANs today is the differences between switches and directors and how to use them. Another puzzler is which topology to choose for your SAN. Prior to Fibre Channel, there was only one real topology option, the SCSI bus. Today, there are many possible topologies and network design choices to make. This article explains what some of those differences are and gives some guidance how topologies can be changed in response to changing requirements. (Feb. 2002)