User Manual

SCSI Commands Reference Manual, Rev. J 433
www.seagate.com Parameters for direct access devices
5.3.23 Logical Unit Control mode page (18h) for FC
The Fibre Channel Logical Unit Control mode page (see table 406) contains those parameters that select FCP logical unit
operation options. The implementation of any parameter and its associated functions is optional. The mode page follows the
MODE SENSE and MODE SELECT command rules.
PS bit, SPF bit, PAGE CODE field and PAGE LENGTH field
The PS bit, SPF bit, PAGE CODE field and PAGE LENGTH field are described in 5.2.2.
PROTOCOL IDENTIFIER field
The value in the PROTOCOL IDENTIFIER (see table 406) field defines the SCSI transport protocol to which the mode page applies. For a MODE
SENSE command (see 3.11), the device server shall set the PROTOCOL IDENTIFIER field to one of the values shown in Clause 5.3.23 to indicate
the SCSI transport protocol used by the target port through which the MODE SENSE command is being processed. For a MODE SELECT com-
mand (see 3.9), the application client shall set the PROTOCOL IDENTIFIER field to one of the values shown in Table 406 indicating the SCSI trans-
port protocol to which the PROTOCOL SPECIFIC MODE PARAMETERS apply. If a device server receives a mode page containing a transport
protocol identifier value other than the one used by the target port on which the MODE SELECT command was received, then the command
shall be terminated with CHECK CONDITION status, with the sense key set to ILLEGAL REQUEST, and the additional sense code set to INVALID
FIELD IN PARAMETER LIST.
EPDC (ENABLE PRECISE DELIVERY CHECKING) bit
1 An ENABLE PRECISE DELIVERY CHECKING (EPDC) bit of one indicates that the logical unit shall use the precise delivery function (see
FCP-4).
0 When the EPDC bit is set to zero, the logical unit shall not use the precise delivery function and shall ignore the contents of the CRN field
in the FCP_CMND IU.
The EPDC bit is valid for all types of link connections. If the precise delivery function is not supported and the Fibre Channel Logical Unit Con-
trol mode page is supported by the logical unit, the EPDC bit shall be masked as not changeable and shall follow the MODE SENSE and MODE
SELECT command rules
(see 3.9).
Table 406 Fibre Channel Logical Unit Control mode page (18h)
Bit
Byte
7 6 5 4 3 2 1 0
0 PS SPF (0b) PAGE CODE (18h)
1 PAGE LENGTH (06h)
2 Reserved PROTOCOL IDENTIFIER (FCP = 0h)
3 Reserved EPDC
4 Reserved
5 Reserved
6 Reserved
7 Reserved