Subject: RE: iSCSI: Use of the A bit

From: "Julian Satran" <[email-masked]>
Date: Fri, 15 Mar 2002 21:50:44 +0200

That could be so but it would be overkill. Status ACK can implicitly 
acknowledge the last transfer.
And Yes the fact that the last transfer is not mentioned is an oversight 
that I will correct.
This does not mean that you HAVE TO raise the A flag or that you are 
ENCOURAGED to do so :-)

Julo

Paul Koning <[email-masked]>
Sent by: [email-masked]
15-03-02 16:09
Please respond to Paul Koning

        To:     [email-masked]
        cc:     [email-masked], [email-masked]
        Subject:        RE: iSCSI: Use of the A bit

>>>>> "Eddy" == Eddy Quicksall <[email-masked]> writes:

 Eddy> I think we may need better explanation about why some folks
 Eddy> don't want to do the "positive ack".

 >> We got to this position, since so many folks did not want to
 >> support the positive ack.

Something doesn't compute here.

I don't believe the discussion has anything to do with whether you
support positive ACK or not.  If you're doing error recovery level 1
or above, then you are required to support it, because the other end
is allowed to say A=1 and you're required to answer that.

If you don't want to support positive ACK, the solution is to support
only error recovery level 0.

The issue under discussion is whether the rule "you are allowed to set
A=1 only once per MaxBurstSize" is correct.  At this point it's clear
to me that it is not, because you need to be able to set A=1 at the
end of the transfer.  The current rule forbids that unless the total
transfer size is >= MaxBurstSize.

Kevin's proposal is a simple fix to this problem.

                  paul

---

From: "Mallikarjun C." <[email-masked]>
Date: Fri, 15 Mar 2002 20:21:41 -0800

I agree with Julian.

Seems to me that targets should be allowed to ask for an ack
on the last Data-In PDU that concludes the entire transfer for the
task - a follow-up NOP-ping is needless.  I propose that we

replace:
  "it MAY set the A bit to 1 only once every MaxBurstSize bytes and MUST NOT do so more frequently than this."

with:
  "it MAY set the A bit to 1 only once every MaxBurstSize bytes or on the last
   Data-In PDU that concludes the entire requested transfer from the target's
   perspective, and MUST NOT do so more frequently than this."
--
Mallikarjun

Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions Organization
Hewlett-Packard MS 5668
Roseville CA 95747
[email-masked]

---

From: Paul Koning <[email-masked]>
Date: Sat, 16 Mar 2002 11:16:47 -0500

>    perspective, and MUST NOT do so more frequently than this."

Sounds good to me.  As far as I can tell, this matches the intent of
what Eddy and Kevin were talking about.

     paul