What is a SAN?
A SAN (Storage Area Network) is a network specifically dedicated to the task of transporting data for storage and retrieval.
SAN's are alternatives to storing data on disks directly attached to servers or storing data on Network Attached Storage (NAS) devices which are connected through general purpose networks.
SAN (Storage Area Network) Protocols
SAN's are traditionally connected over Fibre Channel networks. SAN's have also been built using SCSI (Small Computer System Interface) technology. An Ethernet network which was dedicated solely to storage purposes would also quality as a SAN.
iSCSI (Internet Small Computer Systems Interface) is a SCSI variant which encapsulates SCSI data in TCP packets and transports them over IP networks.
Fibre Channel over TCP/IP (FCIP) tunnels Fibre Channel over IP-based networks.
The Internet Fibre Channel Protocol (iFCP) transports Fibre Channel Layer 4 FCP on IP networks.