What is an FC layer

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FC layer model (fiber channel reference model)

The FibreChannel protocol is structured in five layers, which are much finer than the OSI layer model; they all appear in the network layer of the OSI model. The hierarchical model begins with the lowest physical layer FC-0. It specifies transmission media, their parameters, connections and data - [@ throughput] (from 133 Mbit / s up to 1.0625 Gbit / s). In layer FC-1, signals are coded and decoded, mostly in [@ 8B / 10B] coding. Layer 2 takes over the [@flow control] of the data with the help of the [@ credit procedure], which controls the data transmission between data buffers ([@BB_Buffer]) and devices. On the third level, FC-3, the transmission is adapted to the type of transmission: The same information is sent to many recipients as a “multicast” transmission; "Striping" increases the bandwidth by connecting ports in parallel. The top level FC-4 regulates interfaces for applications and the adaptation to "higher" protocols - here the data transmissions adapt to protocols for exchange with other networks or devices, i.e. TCP / IP for the Internet, SCSI for disk systems, and so on. Only above this, i.e. in the next OSI layer, are the "Upper Level Protocols" (ULP), which define, for example, whether a FiberChannel network functions as a SAN or simply as a conventional IP network.

Glossary - F.