Seagate Fibre Channel Interface - Manual (Page 40)

26 Fibre Channel Interface Manual, Rev. D
OX_ID (Originator Exchange Identifier)
This 2-byte field is assigned by the originator of an exchange. For SCSI FCP frames, this value is analogous to the Queue
Tag used in Parallel SCSI and must be unique for an initiator/drive pair.
R_CTL (Routing Control)
This one-byte field provides routing bits and information bits to categorize the frame function.
The high order bits (bits 31-28) indicate the frame type as indicated below:
0000 = FC-4 Device_Data frame
0010 = Extended Link_Data frame
0011 = FC-4 Link_Data frame
0100 = Video_Data frame
1000 = Basic Link_Data frame
1100 = Link_Control frame
Others = Reserved
The low order bits (bits 27-24) contain the Information field values. This is dependent on the value of the high order bits (31-
28). If the high order bit value = 1000, the Information field contains a basic link service. For all other high order bit values,
the Information field specifies the Common Information Categories specified in the table below.
Table 10: Routing Control values
High order bits Low order bits Use
Type 08h, SCSI FCP, Device Data frames
0000
0000 Uncategorized Not supported
0001 Solicited Data Read and write data
0010 Unsolicited Control Not supported
0011 Solicited control Not supported
0100 Unsolicited data Not supported
0101 Data descriptor Transfer ready
0110 Unsolicited command Command
0111 Command status Response
Type 01h, Extended link service
0010
0000 Uncategorized Not supported
0001 Solicited data Not supported
0010 Unsolicited control Request
0011 Solicited control Reply
0100 Unsolicited data Not supported
0101 Data descriptor Not supported
0110 Unsolicited command Not supported
0111 Command status Not supported
Type 00h, Basic link service
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