Re: iSCSI : On the subject of R2T and Task Tags.

[Matt Wakeley <matt_wakeley@agilent.com>]

Santosh Rao wrote:

> I agree with Matt on the semantics of "Target Task Tag" for WRITE PDUs and would
> also like to request a "Target Task Tag" per task for WRITE PDUs.
> 
> In addition, since multiple R2Ts can be outstanding, an additional qualifier is
> required to track the R2T (Target R2T Tag) along the lines of a (RX_ID + SEQ_ID)
> that Fibre Channel uses.

I don't think an additional qualifier is needed.  For what purpose?

The target just sends out all the R2Ts, and counts all the bytes coming back
(remember - TCP guarantees to deliver each byte only once!).  Also remember,
the iSCSI spec mandates that the initiator send only what was requested in the
R2T... nothing more.

-Matt Wakeley
Agilent Technologies

> 
> Thanks,
> Santosh