Hello Giovanni
The first thing we should do is determine the difference between a LAN and a SAN. A LAN is already well defined within the Introduction to LANs lesson. A SAN is a storage area network, which is a network architecture that is used to provide access to consolidated data storage. This is often used within a datacenter to provide servers with direct high-speed access to a shared storage repository.
SANs can use conventional Layer 2 networking protocols such as Ethernet, but must often use a specialized Layer 3 protocol called Fiber Channel (FC) which was developed specifically for SANs. Unusual for network protocols, FC was actually developed by the International Committee for Information Technology Standards (INCITS) which is an ANSI accredited body.
A SAN switch is simply a switch that has FC ports.
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I hope this has been helpful!
Laz