Seagate Fibre Channel Interface - Manual (Page 139)

Fibre Channel Interface Manual, Rev. D 125
11.0 SCSI operations
SCSI information is transported in Fibre Channel frames. All SCSI Fibre Channel Protocol (SCSI-FCP) opera-
tions start with an FCP CMND (Command) frame and end with an FCP RSP (Response) frame. Operations ini-
tiated with an FCP CMND may be SCSI commands such as read or write data. The operations also include
control operations called Task Management functions. Task Management functions provide reset and Task Set
(queue) control.
11.1 SCSI-FCP
SCSI-FCP is an FC-4 mapping protocol for applying the SCSI command set to the Fibre Channel. This proto-
col retains the half-duplex nature of parallel SCSI within each I/O operation. For example, a single operation,
such as a Read command, operates over a single port pair between the initiator and target.
11.1.1 FC-4 mapping layer
All devices communicating with a Seagate Fibre Channel disc drive must implement the SCSI-FCP mapping
protocol. The FC-4 mapping layer uses the services provided by FC-PH to execute the steps required to per-
form the functions defined by the FC-4.
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