Re: iSCSI: Rev 07 Comments

["Jim Hafner" <hafner@almaden.ibm.com>]

Bill,

As a work-in-progress, my apologies for the confusion.

The iSCSI model defines portal groups as collections of network portals
that can coordinate (at it's end) multiple connections within a session.
That's true for the initiator side and the target side.  I had thought that
the defintion was initiator/target agnostic (I'll have to go back and read
it again, in context).

Keep in mind that there are two models playing here, the iSCSI model and
the SAM/SCSI model.   Portal groups are constructs of the iSCSI model and
are symmetric with respect to initiator or target.  The only non-symmetry
at the iSCSI level is in the identifiers for network portals.  Target
network portals have to have an ipaddress AND a listening tcpport (server
socket).  Initiator network portals don't "listen", so they only have
ipaddresses.

It so happens that as we've proposed the SAM/SCSI model overlay on iSCSI
constructs, only the target portal group plays a role; the initiator portal
group is "invisible" to the SAM/SCSI model.    Hence, the lack of emphasis
on the initiator portal group.  There is definite asymmetry here and we've
tried to justify the value in that in other postings.   When we get to
"initiator requirements", we start having to mention them for other reasons
(as has been discussed in other threads);  namely, where they get there
iSCSI Name and the ISID namespace they use.

Does that help?  And yes, this whole stuff will need a couple more careful
reading/rewritings to get it all correct and clear.

Jim Hafner


"Bill Moody" <bmoody@Crossroads.com>@ece.cmu.edu on 08/15/2001 02:16:04 pm

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


To:   "IP Storage Mailing List (E-mail)" <ips@ece.cmu.edu>
cc:   "Robert Griswold" <rgriswold@Crossroads.com>, "Bill Moody"
      <bmoody@Crossroads.com>
Subject:  iSCSI:  Rev 07 Comments



I have a couple of points I'd like to raise concerning the 07 version of
the document.

Section 1.5.3.  On page 39, under 'iSCSI Initiator Requirements' the
term initiator portal group is used multiple times.  This is the first
use of this term and led to some confusion on my part.  The 'portal
group' term was clearly defined earlier and was used repeatedly in
connection with the target but no mention has been made of the use of
initiator portal groups prior to this point.  The ISID RULE clearly
defines that only one session with a given ISID can exist between a
given iSCSI Initiator and iSCSI Target Portal Group - it doesn't mention
initiator portal groups.  It would be nice to define this 'initiator
portal group' term prior to its use.

Appendix A.  What is the meaning of the value '11EDC6F41' in the table?
Is this the generator polynomial that is discussed in the following
paragraph?  If so, it is not clear.

Thanks,

Bill Moody
Architect
Crossroads Systems, Inc.
Phone:  (512) 928-7238
Fax:  (512)-928-7402