Disposition of short or long SSP frames in SAS

Gerry.Houlder at seagate.com Gerry.Houlder at seagate.com
Thu Apr 10 07:59:00 PDT 2008

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Clause describes the reasons a NAK(CRC ERROR) primitive is
generated. It states:
The frame had a bad CRC, or an invalid dword or an ERROR was
received during frame reception.
There are no requirements for frame length checking on the state machine
that generates NAK. That is because different frame types have different
length requirements (e.g., Command frames and Response have shorter
requirement than data frames). The length checking has to be done at a
higher level, not the link layer.
I would expect a frame sent by an initiator with a good CRC to get an ACK,
then later the response frame would be returned with some kind of error
reported (ther error report would depend on the type of frame had a length
error). If such a frame was sent by a target, there might be no indication
of an error visible on the interface; the initiator would have to detect
the error at a higher level than the link level and fail the command even
if the target sent a GOOD status.
	     Gary.Franco at emule						   
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				       Disposition of short or long SSP    
	     04/10/2008 05:04	       frames in SAS			   
During SSP frame reception if the frame was either too short (less than 6
DWORDS) too long (greater than 262 DWORDS) and the CRC was good, should a
NAK be generated for the frame?
I cannot find anything about this in the SAS 2.0 Rev 14 spec
Gary Franco Consultant Engineer
Emulex Network Systems
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