TPTT setting for multiple XFER_RDY by a WRITE command

Wooseok Chang wooseokc at
Mon Jun 15 23:50:42 PDT 2009

* From the T10 Reflector (t10 at, posted by:
* Wooseok Chang <wooseokc at>
I was looking for who I could ask this kind of questions.
We are developing SAS target devices and found some description about
TPTT (Target Port Transfer Tag) in the SAS spec is somewhat ambiguous.
When the target sends multiple XFER_RDY's for a WRITE command to
transfer multiple series of DATA frames, is the target supposed to set
the TPTT value in each XFER_RDY frame with a different value, or the
same value, or don't care?
I think the DATA frames are all in the same context conceptually, but
the spec sounds like we may need to fill the TPTT field with another
value .
Please, let me know what the spec means, or where to contact to ask
such a SAS protocol question.
Thank you.
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