The SCSI protocol was initially used inside computers to connect hard disks at a higher speed. Later, SANs were built where storage was separated from the computers and consolidated. The FC protocol provided the infrastructure to encapsulate the SCSI traffic and provided connectivity between computers and storage. FC operates at speeds of 2, 4, 8, and 16 Gbps.

FC consists of the following:

• Hard disk arrays: They provide raw storage capacity
• Storage processors: They manage hard disks and provide storage LUNs and masking for the servers
• FC switches (also known as fabric): They provide connectivity between storage processors and server HBAs
• FC host bus adapters: They are installed in the computer and provide connectivity to the SAN

FC identifies infrastructure components with World Wide Numbers (WWNs). WWNs are 64-bit addresses, which uniquely identify the FC devices. Like MAC addresses, they have bits assigned to vendors to identify their devices. Each end device (such as an HBA port) is given a World Wide Port Number (WWPN or pWWN) and each connectivity device (such as a fabric switch or multiport HBA) is given a World Wide Node Number (WWNN).

An FC HBA, used for connecting to a SAN, is known as an initiator, and an FC SAN, providing disks as LUNs, is known as a target.

The FC protocol stack is different from Ethernet or TCP/IP protocols. Hence, it has its own learning curve for professionals with a networking and systems administration background.