Table of Contents
Advertisement
1.2.2
Frame Structure (Refer to FC-PH, Chapter 17)
A frame format is shown in Figure 1.5.
byte count
4
Frame
fill words
SOF
Header
word count
1
a)
SOF
b)
Frame Header ; Used as link control, drive protocol transfer and detect error condition.
word/byte
0
1
2
3
4
5
R_CTL
D_ID
S_ID
TYPE
F_CTL
SEQ_ID
DF_CTL
SEQ_CNT ; Sequence Count, identifies the order of the frames.
OX_ID
RX_ID
OFFSET
c)
Payload
d)
CRC
e)
EOF
24
0-2048+64 (optional header)
Payload
6
0-528
Figure 1.5
Frame Format
; Start of frame indicates the beginning of the frame.
The frame header format is listed in Table 1.2.
Table 1.2
Frame header format
0 (bits 31 – 24) 1 (bits 23 – 16) 2 (bits 15 – 08) 3 (bits 07 – 00)
R_CTL
reserved
TYPE
SEQ_ID
DF_CTL
OX_ID
; Routing Control to categorize the frame.
; Destination Identifier, N_port address to which the frame is being sent.
; Source Identifier, N_port address originating the frame.
; Data Structure Type, identifies the frame protocol.
; Frame Control information
; Sequence Identifier, uniquely identifies frames in a non-streamed sequence.
; Data Field Control, specifies the optional headers in the payload.
This field is not supported by the drive and used as 00h.
; Originator Exchange Identifier, assigned by the originator of an exchange.
This value is similar to Queue Tag in SCSI and must be unique for a
pair between the intiator and the drive.
; Responder Exchange Identifier, generated by the responder for a exchange.
; Defines the relative displacement of the first byte of the payload from
the base address of the command.
; Data field, must be multiple of four bytes.
–If the frame is FC-4 Device Data, the payload has SCSI CDB,
Read/Write Data or status/sense information.
–If the frame is Link Data, the payload has control information for the
drive or the response data to the initiator.
; Calculates without including SOF and EOF delimiters.
; End of frame indicates the end of a frame.
C141-E054-02EN
4
4
CRC
EOF
fill words
1
1
D_ID
S_ID
F_CTL
SEQ_CNT
RX_ID
OFFSET
min24
min6
1 - 7
Advertisement
Table of Contents
