Subject: RE: iSCSI: v15 R2T and DATA-OUT

From: "Julian Satran" <[email-masked]>
Date: Fri, 26 Jul 2002 02:53:12 +0300

Rod,

Probably a very long day. LUN is present in the command. Command is 
associated with ITT. R2T can be checked for a consistent ITT and LUN.
End-story.

Julo

"Rod Harrison" <[email-masked]>
07/25/2002 06:49 AM

        To:     <[email-masked]>
        cc:     Julian Satran/Haifa/IBM@IBMIL
        Subject:        RE: iSCSI: v15 R2T and DATA-OUT

                 OK, it's been a long day. Let me try this one more time.

                 I was write (almost) first time but I meant DATA-OUT 
instead of
DATA-IN. Here's what I meant to say ...

                 There is a potential inconsistency in the description of 
the use of
the LUN field in DATA-OUT and R2T in the working v15 draft.

                 9.7.3 Target Transfer Tag, for DATA-OUT last paragraph 
says ...

                 "If the Target Transfer Tag is provided, then the LUN 
field MUST hold
a valid value and be consistent with whatever was specified with the
command;"

                 9.8.5 Target Transfer Tag, for R2T says ...

                 "The Target Transfer Tag and LUN are copied in the 
outgoing data PDUs
and are used by the target only."

                 Potentially a target could return a different LUN field 
in the R2T,
for perhaps some funky LUN mapping or other internal reason expecting
it to be copied to the DATA-OUT as per the R2T text.

                 I think we need to indicate what is expected of the 
initiator if the
LUN field in the R2T does not match the LUN in the command PDU.

                 - Rod

-----Original Message-----
From: Rod Harrison [mailto:[email-masked]]
Sent: Wednesday, July 24, 2002 8:57 PM
To: Julian Satran
Cc: [email-masked]
Subject: RE: iSCSI: v15 R2T and DATA-OUT

                 Oops, I see the confusion. I said DATA-IN in my message 
when I meant
DATA-OUT.

                 However, re-reading the section of v15 in question I now 
see that the
third paragraph is referring to the DATA-IN LUN, not the DATA-OUT LUN.
That wasn't clear to me when first scanned it because of the paragraph
break.

                 Perhaps a note of clarification needs to be added?

                 - Rod

-----Original Message-----
From: Rod Harrison [mailto:[email-masked]]
Sent: Wednesday, July 24, 2002 8:51 PM
To: Julian Satran
Cc: [email-masked]
Subject: RE: iSCSI: v15 R2T and DATA-OUT

Julian,

                 I think you've misread my message. I was questioning how 
the
initiator should handle the LUN between an R2T and the DATA-OUT(s)
that satisfy it.

                 DATA-OUT says copy the LUN from the command PDU, R2T says 
copy the
LUN from the R2T to the DATA-OUT. Which is correct if the R2T contains
a different LUN than that in the command PDU?

                 - Rod

-----Original Message-----
From: Julian Satran [mailto:[email-masked]]
Sent: Wednesday, July 24, 2002 5:00 PM
To: Rod Harrison
Cc: [email-masked]; [email-masked]
Subject: Re: iSCSI: v15 R2T and DATA-OUT

There is no TTT for data-In. Julo

                      "Rod Harrison"
                      <rod.harrison@win        To:
<[email-masked]>
                      driver.com>              cc:
                      Sent by:                 Subject:  iSCSI: v15
R2T and DATA-OUT
                      [email-masked]
                      .edu

                      07/24/2002 10:24
                      PM

Folks,

             There is a potential inconsistency in the description of
the
use of
the LUN field in DATA-OUT and R2T in the working v15 draft.

             9.7.3 Target Transfer Tag, for DATA-IN last paragraph
says ...

             "If the Target Transfer Tag is provided, then the LUN
field
MUST hold
a valid value and be consistent with whatever was specified with the
command;"

             9.8.5 Target Transfer Tag, for R2T says ...

             "The Target Transfer Tag and LUN are copied in the
outgoing
data PDUs
and are used by the target only."

             Potentially a target could return a different LUN field
in the
R2T,
for perhaps some funky LUN mapping or other internal reason expecting
it to be copied to the DATA-OUT as per the R2T text. I suspect we just
want to say this is not allowed and the LUN field MUST be the same as
the command PDU.

             Either way I think we need to indicate what is expected
of the
initiator if the LUN field in the R2T does not match the LUN in the
command PDU.

             Apologies for not spotting this before the end of last
call.

             - Rod

---

From: "Rod Harrison" <[email-masked]>
Date: Thu, 25 Jul 2002 19:08:47 -0500

Julian,

	OK, that's the answer to my question then. The wording that's there
right now doesn't say what the initiator should do if the LUN in an
R2T doesn't match the LUN it sent in the command PDU.

	So the resolution is that the initiator should treat a LUN
inconsistency between R2T and command as a protocol error. I suggest
we add a note to that effect where we talk about LUN in the R2T PDU
description, that would be 9.8.5 in the v15 working draft.

	- Rod

-----Original Message-----
From: Julian Satran [mailto:[email-masked]]
Sent: Thursday, July 25, 2002 6:53 PM
To: Rod Harrison
Cc: [email-masked]
Subject: RE: iSCSI: v15 R2T and DATA-OUT

Rod,

Julo

        To:        <[email-masked]>

                OK, it's been a long day. Let me try this one more
time.

                There is a potential inconsistency in the description
of the use of
the LUN field in DATA-OUT and R2T in the working v15 draft.

                Potentially a target could return a different LUN
field in the R2T,
for perhaps some funky LUN mapping or other internal reason expecting
it to be copied to the DATA-OUT as per the R2T text.

                - Rod

-----Original Message-----
From: Rod Harrison [mailto:[email-masked]]
Sent: Wednesday, July 24, 2002 8:57 PM
To: Julian Satran
Cc: [email-masked]
Subject: RE: iSCSI: v15 R2T and DATA-OUT

                Oops, I see the confusion. I said DATA-IN in my
message when I meant
DATA-OUT.

                However, re-reading the section of v15 in question I
now see that the
third paragraph is referring to the DATA-IN LUN, not the DATA-OUT LUN.
That wasn't clear to me when first scanned it because of the paragraph
break.

                - Rod

-----Original Message-----
From: Rod Harrison [mailto:[email-masked]]
Sent: Wednesday, July 24, 2002 8:51 PM
To: Julian Satran
Cc: [email-masked]
Subject: RE: iSCSI: v15 R2T and DATA-OUT

Julian,

                I think you've misread my message. I was questioning
how the
initiator should handle the LUN between an R2T and the DATA-OUT(s)
that satisfy it.

                DATA-OUT says copy the LUN from the command PDU, R2T
says copy the
LUN from the R2T to the DATA-OUT. Which is correct if the R2T contains
a different LUN than that in the command PDU?

                - Rod

-----Original Message-----
From: Julian Satran [mailto:[email-masked]]
Sent: Wednesday, July 24, 2002 5:00 PM
To: Rod Harrison
Cc: [email-masked]; [email-masked]
Subject: Re: iSCSI: v15 R2T and DATA-OUT

                     "Rod Harrison"
                     <rod.harrison@win        To:
<[email-masked]>
                     driver.com>              cc:

                     07/24/2002 10:24
                     PM

Folks,

            - Rod