I'm trying to wrap my head around how a SAN works and how it is implemented.

If I understand this well, clients wanting to access the storage devices in a SAN need to communicate with the servers via the LAN. When the SAN is implemented with Fibre Channel, these servers are Fibre Channel compliant devices, and internally in the SAN they work with the Fibre Channel Protocol. Both data and communications are supported by Fibre Channel.

But which application-layer protocol do the clients use in the LAN to communicate with the servers? Is the data simply transferred via ethernet as well? This is some part I am stuck on. I went trough a lot of sources but most sources don't really mention protocols and if they do, they only mention FCP.