User guide

Fibre Channel Technology
Figure D-4 shows the structure of Fibre Channel data transmission.
Exchange
Sequence
Data
Fibre Channel
Frame
Sequence 1
Sequence 2
Sequence 3
SOF
CRC
EOF
Header
Figure D-4. Structure of data transmission over Fibre Channel cable
Five protocol layers are included in the Fibre Channel standard. They are FC-0
through FC-4.
FC-0 defines the physical characteristics of the interface used. It also includes
the cable type, connectors, drivers, (short-wave lasers, long-wave lasers)
transmitters, and receivers.
FC-1 defines the 8B/10B encoding/decoding and transmission protocol used to
integrate data with the clock information necessary for serial transmission.
FC-2 defines the framing and signaling protocol level. It defines how data is
transported over the Fibre Channel cable. Frames are visible, data flow is not
seen.
FC-3 supports common services. This is the layer that provides the transport
service calls to all the FC-4 modules.
FC-4 supports mapping of the upper level protocols (SCSI protocol) to the
lower levels of Fibre Channel.