Fibre Channel layers

Fibre Channel (FC) is broken up into a series of five layers. The concept of
layers, starting with the ISO/OSI seven-layer model, allows the development of
one layer to remain independent of the adjacent layers. Although, FC contains
five layers, those layers follow the general principles stated in the ISO/OSI
model.

• FC0 The physical layer, which includes cables, fiber optics, connectors, pinouts etc.

• FC1 The data link layer, which implements the 8b/10b encoding and decoding of signals.

• FC2 The network layer, defined by the FC-PI-2 standard, consists of the core of Fibre Channel, and defines the main protocols.

• FC3 The common services layer, a thin layer that could eventually implement functions like encryption or RAID.

• FC4 The Protocol Mapping layer. Layer in which other protocols, such as SCSI, are encapsulated into an information unit for delivery to FC2.

FC0, FC1, and FC2 are also known as FC-PH, the physical layers of fibre channel.
Fibre Channel routers operate up to FC4 level (i.e. they may operate as SCSI routers), switches up to FC2, and hubs on FC0 only.

The layers in the table represent different functions that exists within a Fibre channel system.