Re: iSCSI: is TargetName always mandatory or not?

[Steve Senum <ssenum@cisco.com>]

(This is a resend with the proper subject line)

As I have said before, since authentication may need
InitiatorName and (if not a discovery session)
TargetName, both should be present in the first Login
of every connection.

Steve Senum


John Hufferd wrote:
> 
> Andre,
> I looked again through the document and No where could I find a statement
> that you claimed as "a nexus, and therefore an iSCSI session, is uniquely
> identified by the InitiatorName, ISID, TSID, and portal group tag".  It is
> the InitiatorName, ISID, TSID, with the TargetName and PortalGroup.
> 
> Please point out to me in the Spec (8 or above), where  I can find your
> statement on I_T Nexus.
> 
> I did find the following (please ignore for this conversation the "i" and
> 't" stuff):
> 
> "- Session: The group of TCP connections that link an initiator with a
> target, form a session (loosely equivalent to a SCSI I-T nexus). TCP
> connections can be added and removed from a session. Across all connections
> within a session, an initiator sees one "target image".  "
> 
> " - I_T nexus: According to [SAM2], the I_T nexus is a relationship between
> a SCSI Initiator Port and a SCSI Target Port. For iSCSI, this relationship
> is a session, defined as a relationship between an iSCSI Initiator's end of
> the session (SCSI Initiator Port) and the iSCSI Target's Portal Group. The
> I_T nexus can be identified by the conjunction of the SCSI port names; that
> is, the I_T nexus identifier is the tuple (iSCSI Initiator Name + 'i'+
> ISID, iSCSI Target Name + 't'+ Portal Group Tag). NOTE: The I_T nexus
> identifier is not equal to the session identifier (SSID).  "
> 
> I have not found a place where Session ID is tied to the TSID.
> 
> Hence my comment that we also need to have the TargetName in the Initial
> Login on all Connections.
> 
> .
> .
> .
> John L. Hufferd
> Senior Technical Staff Member (STSM)
> IBM/SSG San Jose Ca
> Main Office (408) 256-0403, Tie: 276-0403,  eFax: (408) 904-4688
> Home Office (408) 997-6136
> Internet address: hufferd@us.ibm.com
> 
> Andre Asselin/Raleigh/IBM@IBMUS@ece.cmu.edu on 10/31/2001 10:40:55 AM
> 
> Sent by:  owner-ips@ece.cmu.edu
> 
> To:   ips@ece.cmu.edu
> cc:   John Hufferd/San Jose/IBM@IBMUS
> Subject:  Re: is TargetName always mandatory or not?
> 
> John & Julian,
>      How about this for the section 5 text:
> 
> The initial Login request of the first connection of a session (leading
> login) MUST include the InitiatorName key=value pair. The initial login
> request
> of the leading Login MAY also include the SessionType key=value pair, in
> which case if the SessionType is not "discovery", then the initial login
> request
> MUST also include the key=value pair TargetName.
> 
> John,
>      I disagree with your second statement: I don't see any way you could
> have 2 different sessions established within the same portal group with the
> same InitiatorName, ISID, and TSID.  The spec. says that a nexus, and
> therefore an iSCSI session, is uniquely identified by the InitiatorName,
> ISID, TSID, and portal group tag.  There is no mention of TargetName
> contributing to the identificaiton of a session.  In my opinion, a
> non-leading connection should NOT have the TargetName, since it doesn't
> contribute anything.
> 
> Andre Asselin
> IBM ServeRAID Software Development
> Research Triangle Park, NC
> 
>                     John
>                     Hufferd/San          To:     Julian
> Satran/Haifa/IBM@IBMIL
>                     Jose/IBM@IBMUS       cc:     ips@ece.cmu.edu
>                     Sent by:             Subject:     Re: is TargetName
> always mandatory or not?
>                     owner-ips@ece.
>                     cmu.edu
> 
>                     10/31/2001
>                     04:20 AM
> 
> Julian,
> I think the TargetName should be included on the Initial Login Request on
> the Leading Login.  It seem strange to permit the Authentication functions
> to proceed if perhaps the intended Target is different then the one doing
> the Authentication.  The way it currently is written, you could pass all
> the Security test and then find out just before going into Full Function
> Phase, that it was intended for some other Target.  Seems like a waste.
> 
> My I think that TargetName should also be on all connections on the Initial
> Login Request.  Here is my thinking:
> 
> The SSID (ISID+TSID) is unique only with regards to a Specific Initiator
> and Target Node Pair.  It is therefore not clear that just knowing the SSID
> and InitiatorName is enough to understand what session the subsequent
> connections are being attached to.  And it is possible that the CID could
> be also overlapped with another session.
> 
> Therefore, I think it make since to determine all this on the initial Login
> on every Connection, so you know at the beginning what values can be
> negotiated, or that are being set to the right Session.
> 
> .
> .
> .
> John L. Hufferd
> Senior Technical Staff Member (STSM)
> IBM/SSG San Jose Ca
> Main Office (408) 256-0403, Tie: 276-0403,  eFax: (408) 904-4688
> Home Office (408) 997-6136
> Internet address: hufferd@us.ibm.com
> 
> Julian Satran/Haifa/IBM@IBMIL@ece.cmu.edu on 10/30/2001 11:33:50 PM
> 
> Sent by:  owner-ips@ece.cmu.edu
> 
> To:   ips@ece.cmu.edu
> cc:
> Subject:  Re: is TargetName always mandatory or not?
> 
> It is the leading login:
> 
> The section 5 paragraph will read:
> 
> The initial Login request of the first connection of a session (leading
> login) MUST include the InitiatorName key=value pair. The leading Login
> request MAY also include the SessionType key=value pair in which case if
> the SessionType is not "discovery" then the leading Login Request MUST
> also include the key=value pair TargetName.
> 
> Julo
> 
> Andre Asselin/Raleigh/IBM@IBMUS
> Sent by: owner-ips@ece.cmu.edu
> 31-10-01 02:08
> Please respond to Andre Asselin
> 
>         To:     "IPS Reflector (E-mail)" <ips@ece.cmu.edu>
>         cc:
>         Subject:        is TargetName always mandatory or not?
> 
>      In section 5 of the spec, it says "If the SessionType is not
> "discovery" then the initial Login Request MUST also include the key=value
> pair TargetName.".  However, in Appendix D, the description for TargetName
> says it is Leading Only.
>      Should TargetName not be Leading Only, or should the text in section
> 5
> say that TargetName must be in the initial Login Request of a leading
> connection?
> 
> Andre Asselin
> IBM ServeRAID Software Development
> Research Triangle Park, NC