Subject: Re: iSCSI: definitions

From: "Jim Hafner" <[email-masked]>
Date: Tue, 1 Jan 2002 13:36:20 -0800

Eddy,

Apologies, this reply is a bit out of order (I've only been doing a
scattered job of handling e-mail this season).
I think there's a "perspective" difference going on here.

First, SAM has defined "abstract" structures, not real things.  It is the
protocols that specify the "implemention" of the abstract model defined by
SAM. In light of this, you're third question is phrased backwards!  iSCSI
defines the iSCSI Target Node name, then maps that to the SCSI target
device name.   As in my other note, iSCSI defines its concrete architecture
and then maps those to SCSI stuff.

Second, (as you note in your first point) there are two different generic
definitions for the term "initiator" and "target" and it depends on which
document you're reading.  If you read SAM (or any T10 document), the term
"initiator" is a synonym for "SCSI initiator port" and "target"="SCSI
target port".  See the glossary of SAM-2.
However, in the iSCSI draft (and I think it says this somewhere in the
glossary or early in the document), the term "initiator" is a synonym for
"iSCSI Initiator Node" and "target"="iSCSI target node".
*I believe this is one source of the confusion we're seeing!*.

To be consistent with SAM-2, the iSCSI document would have a major "Find
and Replace" job.  I have no objections to that.  (In all my notes and text
in the iSCSI draft, I have tried to never be ambiguous but to fully qualify
the terms in every case -- though I may have failed in some cases :-{))

We don't specifically define either the term "iSCSI Initiator" or the term
"iSCSI Initiator Portal Group". However, we do define the term "iSCSI Node"
and "iSCSI Portal Group" -- and these can both come in "initiator" flavor
as well as "target" flavor.    Perhaps we need to be more pendantic.

Jim Hafner

"Eddy Quicksall" <[email-masked]>@ece.cmu.edu on 12/29/2001 08:
16:28 AM

Sent by:    [email-masked]

To:    Julian Satran/Haifa/IBM@IBMIL
cc:    "ips@ece. cmu. edu \(E-mail\)" <[email-masked]>
Subject:    iSCSI: definitions

1) SAM-2 defines ?initiator? as ?a SCSI initiator port?. iSCSI uses
?initiator? to mean the ?SCSI Initiator Device? as in ?iSCSI Initiator
Node: The "initiator"? (because we say ?there can be at most one SCSI
Device within a given iSCSI Node? so the node is the device).

Should we be consistent with SAM-2?

2) We don?t specifically define the ?iSCSI Initiator? (I agree ... it is
implied to be the same as iSCSI Initiator Node).

My I suggest we define it based on the answer to question 1?

3) Is the iSCSI Target Name equivalent to the SCSI Target Device Name? If
so, can we specify that?

Eddy