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    RE: iSCSI version 20 draft


    • To: <ips@ece.cmu.edu>
    • Subject: RE: iSCSI version 20 draft
    • From: "Elliott, Robert (Server Storage)" <Elliott@hp.com>
    • Date: Wed, 22 Jan 2003 12:34:38 -0600
    • content-class: urn:content-classes:message
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    • Sender: owner-ips@ece.cmu.edu
    • Thread-Index: AcLATNK4rZ6V/dVsTaeo6LUGAxknQQB963Zw
    • Thread-Topic: iSCSI version 20 draft

    Sorry to belabor this, but the wording about the affects of connection 
    loss didn't end up like Mallikarjun's final recommendation.
    
    Upon further discussion, we think this would be better:
    
    If the tasks terminated in the above cases are SCSI tasks, they must 
    be internally terminated as if with CHECK CONDITION
    status. This enables ordering to be maintained correctly with respect
    to commands on other connections when ACA is enabled. This enables 
    ordering to be maintained correctly with respect to commands on other 
    connections of the same I_T nexus when ACA is enabled (i.e., commands
    waiting to be processed after those terminated are blocked due to
    the ACA) - see [SAM-3] and [SPC-3].
    
    After the tasks are terminated, the device server shall report a unit 
    attention condition with an additional sense code of COMMANDS 
    CLEARED BY TRANSPORT PROTOCOL EVENT on the next command processed on 
    any connection for each affected I_T_L nexus. This enables ordering to 
    be maintained correctly with respect to commands on other connections 
    of the same I_T nexus when unit attention interlock is enabled (i.e., 
    commands waiting to be processed after those terminated are blocked 
    due to the unit attention interlock) - see [SAM-3] and [SPC-3].
    
    
    The first paragraph explains why the "CHECK CONDITION" part is
    important for the internally terminated tasks. If they were
    allowed to terminate as if they had "GOOD" status, they wouldn't
    invoke ACA.
    
    The second paragraph explains the unit attention that must appear
    on the next command on the wire (and lists the additional sense
    code to use). This is not an additional sense code for an internal-only 
    command status, so is appropriate for iSCSI to mention. We'll assign 
    that code in SPC-3.
    
    
    The text in iscsi-20 is:
    6.5 Implicit termination of tasks
    ...
    If the tasks terminated in the above cases a), b, c) and d)are
    SCSI tasks, they must be internally terminated as if with
    CHECK CONDITION status. This status is only meaningful for
    appropriately handling the internal SCSI state and SCSI side
    effects with respect to ordering because this status is never
    communicated back as a terminating status to the initiator.
    However additional actions may have to be taken at SCSI level
    depending on the SCSI context as defined by the SCSI standards
    (e.g., queued commands and ACA, UA for the next command on the
    I_T nexus in cases a), b), and c) etc. - see [SAM] and [SPC3]).
    
    10.14.5 Implicit termination of tasks
    ...
    If the tasks terminated in any of the above cases are SCSI
    tasks, they must be internally terminated as if with
    CHECK CONDITION status. This status is only meaningful for
    appropriately handling the internal SCSI state and SCSI side
    effects with respect to ordering because this status is never
    communicated back as a terminating status to the initiator.
    However additional actions may have to be taken at SCSI level
    depending on the SCSI context as defined by the SCSI standards
    (e.g., queued commands and ACA, UA for the next command on the
    I_T nexus in cases a), b), and c) etc. - see [SAM] and [SPC3]).
    
    -- 
    Rob Elliott, elliott@hp.com 
    Hewlett-Packard Industry Standard Server Storage Advanced Technology 
    https://ecardfile.com/id/RobElliott 
    
    
    -----Original Message-----
    From: Julian Satran [mailto:Julian_Satran@il.ibm.com] 
    Sent: Sunday, January 19, 2003 11:52 PM
    To: internet-drafts@ietf.org
    Cc: ips@ece.cmu.edu; Allison Mankin
    Subject: iSCSI version 20 draft
    
    
    On behalf of the team of authors and as part of the IETF-IPS working
    group 
    I submit a draft for immediate publication. 
    
    The text and pdf versions can be found at: 
    
    http://www.haifa.il.ibm.com/satran/ips/draft-ietf-ips-iscsi-20.txt 
    http://www.haifa.il.ibm.com/satran/ips/draft-ietf-ips-iscsi-20.pdf 
    
    This version completely replaces: 
    
    draft-ietf-ips-iscsi-19.txt and pdf 
    
    
    The change marks are relative to version 19 and are clarifications
    as requested by Steve Bellovin and typo fixes. 
    All AD concerns and the "nits" where (hopefully) addressed. 
    
    Julian Satran - IBM Research Laboratory at Haifa 
    


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