The topics covered in fibre channel specifications are categorized using five levels, labeled FC-0, FC-1, FC-2, FC-3, and FC-4. Some (but not all) of the levels correspond to protocol layers.
The levels are
FC-0—This level corresponds to the lower part of the physical layer. Its specification defines the characteristics of fibre channel physical media and connectors, and the signals used to place bits onto each medium.
FC-1—This is the part of the physical layer that performs an 8B/10B encoding of data bytes and defines the usage of special code-groups.
The physical media, connectors, signals, and 8B/10B data encoding used for the 1000BASE-LX, SX, and CX implementations of Gigabit Ethernet were borrowed from fibre ...