Re: iSCSI: draft 7: remove S bit and Status field from the Data-in PD U?

["Julian Satran" <Julian_Satran@il.ibm.com>]

Elliott,

That might be so for hardware inplementations. For software it means an
additional read and it may negatively affect performance for short
operations (like data base transactions).

The same is true for immediate writes. The simplification that was agreed
that we bring back to the list
was to eliminate 2 types of unsolicited data and return to only one king
being allowed in a command.

So here it is.  I personally think that the simplification is so minor that
it is not worth going through talking about it.

Comments?

Julo


"Elliott, Robert" <Robert.Elliott@compaq.com>@ece.cmu.edu on 07-08-2001
20:47:44

Please respond to "Elliott, Robert" <Robert.Elliott@compaq.com>

Sent by:  owner-ips@ece.cmu.edu


To:   "'ips@ece.cmu.edu'" <ips@ece.cmu.edu>
cc:
Subject:  iSCSI: draft 7: remove S bit and Status field from the Data-in PD
      U?



At the IETF IPS WG meeting, removing the immediate data from the
Command PDU was discussed as a possible simplification.

A similar simplification would be to remove the S bit and Status
field from the Data-in PDU.  These let Status be returned in the
Data-in PDU rather than in a separate Response PDU.  The target
can send the last Data-in PDU and the Response PDU back-to-back;
there's not much wire overhead sending 48 more bytes.  The
initiator always has to handle separate Response PDUs, so this
eliminates a special case and collects all status and residual
handling in one place.

--
Robert.Elliott@compaq.com
Compaq Computer Server Storage