Re: iSCSI: Use of the A bit

["Mallikarjun C." <cbm@rose.hp.com>]

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
cbm@rose.hp.com

----- Original Message -----
From: "Julian Satran" <Julian_Satran@il.ibm.com>
To: "Paul Koning" <ni1d@arrl.net>
Cc: <Eddy_Quicksall@ivivity.com>; <ips@ece.cmu.edu>; <owner-ips@ece.cmu.edu>; <rod.harrison@windriver.com>
Sent: Friday, March 15, 2002 11:50 AM
Subject: RE: iSCSI: Use of the A bit


> 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 <ni1d@arrl.net>
> Sent by: owner-ips@ece.cmu.edu
> 15-03-02 16:09
> Please respond to Paul Koning
>
>
>         To:     Eddy_Quicksall@ivivity.com
>         cc:     rod.harrison@windriver.com, ips@ece.cmu.edu
>         Subject:        RE: iSCSI: Use of the A bit
>
>
>
> >>>>> "Eddy" == Eddy Quicksall <Eddy_Quicksall@ivivity.com> 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
>
>
>
>