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Versions: 00 01 02 03 04 05 06 07 08 09 RFC 7144

    Storage Maintenance (StorM) Working Group                  F. Knight
    Internet Draft                                                NetApp
    Intended status: Standards Track                      M. Chadalapaka
    Expires: October 2011                            Hewlett-Packard Co.
    Updates: 3720, 5048                                       March 2011
  
  
          Internet Small Computer Systems Interface (iSCSI) SAM
                   draft-ietf-storm-iscsi-sam-02.txt
  
    Abstract
  
       Internet Small Computer Systems Interface (iSCSI) is a SCSI
       transport protocol that maps the SCSI family of protocols onto
       TCP/IP.  RFC 3720 defines the iSCSI protocol.  The current iSCSI
       protocol (RFC 3720 and RFC 5048) is based on the SAM-2 version of
       the SCSI family of protocols). This document defines additions
       and changes to the iSCSI protocol to enabled additional features
       that were added to the SCSI family of protocols through SAM-3,
       SAM-4, and SAM-5.
  
       This document updates RFC 3720 and RFC 5048 and the text in this
       document supersedes the text in RFC 3720 and RFC 5048 when the
       two differ.
  
    Status of this Memo
  
       This Internet-Draft is submitted to IETF in full conformance with
       the provisions of BCP 78 and BCP 79.
  
       Internet-Drafts are working documents of the Internet Engineering
       Task Force (IETF), its areas, and its working groups.  Note that
       other groups may also distribute working documents as Internet-
       Drafts.
  
       Internet-Drafts are draft documents valid for a maximum of six
       months and may be updated, replaced, or obsoleted by other
       documents at any time.  It is inappropriate to use Internet-
       Drafts as reference material or to cite them other than as "work
       in progress."
  
       The list of current Internet-Drafts can be accessed at
       http://www.ietf.org/1id-abstracts.html.
  
       The list of Internet-Draft Shadow Directories can be accessed at
       http://www.ietf.org/shadow.html.
  
       This Internet-Draft will expire October, 2011.
  
    Copyright Notice
  
  
  
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      Copyright (c) 2011 IETF Trust and the persons identified as the
      document authors.  All rights reserved.
  
      This document is subject to BCP 78 and the IETF Trust's Legal
      Provisions Relating to IETF Documents
      (http://trustee.ietf.org/license-info) in effect on the date of
      publication of this document.  Please review these documents
      carefully, as they describe your rights and restrictions with
      respect to this document.  Code Components extracted from this
      document must include Simplified BSD License text as described in
      Section 4.e of the Trust Legal Provisions and are provided without
      warranty as described in the Simplified BSD License.
  
            Table of Contents
  
            1  Introduction........................................... 3
            2  Definitions, Acronyms, and Document Summary............ 3
              2.1   Definitions....................................... 3
              2.2   Acronyms.......................................... 3
              2.3   New Semantics..................................... 3
            3  Terminology Mapping.................................... 4
            4  Negotiation of New Feature Use......................... 7
            5  SCSI Commands.......................................... 8
              5.1   SCSI Command Additions............................ 8
               5.1.1   Command Priority (byte 2)...................... 8
              5.2   SCSI Response Additions........................... 9
               5.2.1   Status Qualifier.............................. 10
               5.2.2   Data Segment - Sense and Response Data Segment 10
            6  Task Management Functions............................. 10
              6.1   Existing Task Management Functions............... 10
              6.2   Task Management Function Additions............... 10
               6.2.1   LUN field..................................... 12
               6.2.2   Referenced Task Tag........................... 12
               6.2.3   RefCmdSN...................................... 12
              6.3   Task Management Function Responses............... 13
               6.3.1   Task Management Function Response Additions... 14
              6.4   Task Management Requests Affecting Multiple Tasks 14
            7  Login/Text Operational Text Keys...................... 15
              7.1   New Operational Text Keys........................ 15
               7.1.1   iSCSIProtocolLevel............................ 15
            8  Security Considerations............................... 16
            9  IANA Considerations................................... 16
            10  References .......................................... 17
            11  Acknowledgements .................................... 18
  
  
  
  
  
  
  
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    1.   Introduction
  
       The original [RFC3720] was built based on the SAM-2 model for
       SCSI.  Several new features and capabilities have been added to
       the SCSI Architecture Model in the intervening years (SAM5 is now
       the current version of the SCSI Architecture Model).  This
       document is not a complete revision of [RFC3720].  Instead, this
       document is intended as a companion document to [RFC3720] and
       [RFC5048].
  
       The text in this document, however, updates and supersedes the
       text in [RFC3720] and [RFC5048] whenever there is any conflict.
  
    2.   Definitions, Acronyms, and Document Summary
  
    2.1  Definitions
  
       The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
       NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
       "OPTIONAL" in this document are to be interpreted as described in
       [RFC2119].
  
    2.2  Acronyms
  
       SAM4    SCSI Architecture Model - 4
       SAM5    SCSI Architecture Model - 5
       SAM     SAM4 or SAM5
  
    2.3  New Semantics
  
       This document specifies new iSCSI semantics.  This section
       summarizes the contents of the document.
  
         Section 3: The mapping of iSCSI objects to SAM5 objects
                    The iSCSI node may contain both initiator and
                    target capabilities.
  
         Section 4: The protocol used to negotiate the use of the new
                    capabilities described in this document.
  
         Section 5: New Command operations
                    The PRI field for SCSI command priority has been
                    added to the SCSI command PDU (see 5.1.1).
                    The Status Qualifier field has been added to the
                    SCSI response PDU (see 5.2.1).
                    Sense data may be returned (via autosense) for any
                    SCSI status, not just CHECK CONDITION (see 5.2.2).
  
         Section 6: New Task Management Functions
  
  
  
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                    Four new task management functions (QUERY TASK,
                    QUERY TASK SET, I_T NEXUS RESET, and QUERY
                    ASYNCHRONOUS EVENT have been added (see 6.2).
                    A new "function succeeded" response has been added
                    (see 6.3.1).
  
         Section 7: New Negotiation key
                    A new negotiation key has been added to enable the
                    use of the new features in section 5 and section
                    6.
  
    3.   Terminology Mapping
  
       The iSCSI model (defined in [RFC3720]) uses different terminology
       than the SCSI Architecture Model.  In some cases, iSCSI uses
       multiple terms to describe what in the SCSI Architecture Model is
       described with a single term.  The iSCSI terms and SAM terms are
       not necessarily equivalent, but rather, the iSCSI terms represent
       examples of the objects or classes described in SAM as follows:
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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           +-----------------------------+---------------------------+
           | RFCxxx Terminology          | SAM Terminology           |
           +-----------------------------+---------------------------+
           | Network Entity              | none                      |
           +-----------------------------+---------------------------+
           | iSCSI Node                  | SCSI Device               |
           +-----------------------------+---------------------------+
           | iSCSI Name                  | SCSI Device Name          |
           +-----------------------------+---------------------------+
           | iSCSI Node Name             | SCSI Device Name          |
           +-----------------------------+---------------------------+
           | iSCSI Initiator Node        | SCSI Initiator Device     |
           +-----------------------------+---------------------------+
           | iSCSI Initiator Name        | SCSI Device Name          |
           +-----------------------------+---------------------------+
           | iSCSI Initiator Port Name   | SCSI Initiator Port Name  |
           |  iSCSI Node Name + ',i,' +  |                           |
           |  ISID                       |                           |
           +-----------------------------+---------------------------+
           | iSCSI Target Node           | SCSI Target Device        |
           +-----------------------------+---------------------------+
           | iSCSI Target Name           | SCSI Device Name          |
           +-----------------------------+---------------------------+
           | iSCSI Target Port Name      | SCSI Target Port Name     |
           |  iSCSI Node Name + ',t,' +  |                           |
           |  Target Portal Group Tag    |                           |
           +-----------------------------+---------------------------+
           | iSCSI Target Portal Group   | SCSI Target Port          |
           +-----------------------------+---------------------------+
           | iSCSI Initiator Node +      | SCSI Initiator Port       |
           |  active ISID                |                           |
           +-----------------------------+---------------------------+
           | iSCSI Initiator Name +      | I_T Nexus                 |
           |  ',i,' + ISID, iSCSI Target |                           |
           |   Name + ',t,' + Portal     |                           |
           |   Group Tag                 |                           |
           +-----------------------------+---------------------------+
           | Target Portal Group Tag     | Relative Port ID          |
           +-----------------------------+---------------------------+
  
           -----------------------------------------------------------
           RFC EDITORS NOTE: The above reference (in row 1) to [RFCxxx]
           should reference this RFC, and this note should be removed.
           -----------------------------------------------------------
  
  
  
  
  
  
  
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       The following diagram shows an example of a combination target
       device and initiator device.  Such a configuration may exist in a
       target device that implements a SCSI Copy Manager.  This example
       shows how a session that shares Network Portals within a Portal
       Group may be established (see Target Portal Group 1).  In
       addition, this example shows the Initiator using a different
       Portal Group than the Target Portal Group, but the Initiator
       Portal group sharing Network Portal A with the Target Portal
       Group.
  
  
     ----------------------------IP Network---------------------
             |               |                    |
        +----|---------------|-------+       +----|------------+
        | +----------+  +----------+ |       | +----------+    |
        | | Network  |  | Network  | |       | | Network  |    |
        | | Portal A |  | Portal B | |       | | Portal A |    |
        | +----------+  +----------+ |       | +----------+    |
        |    |    Target     |       |       |    | Initiator  |
        |    |    Portal     |       |       |    | Portal     |
        |    |    Group 1    |       |       |    | Group 2    |
        +----|---------------|-------+       +----|------------+
             |               |                    |
  +----------|---------------|--------------------|--------------------+
  | +--------|---------------|----+ +-------------|------------------+ |
  | |+-------|---------------|---+| |+------------|-----------------+| |
  | ||iSCSI Session (Target side)|| ||iSCSI Session (Initiator side)|| |
  | ||                           || ||                              || |
  | ||       (TSIH = 56)         || ||        (SSID = 48)           || |
  | |+---------------------------+| |+------------------------------+| |
  | |                             | |                                | |
  | |     iSCSI Target Node       | |      iSCSI Initiator Node      | |
  | +-----------------------------+ +--------------------------------+ |
  |                          iSCSI Node                                |
  |              (within Network Entity, not shown)                    |
  +--------------------------------------------------------------------+
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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    4.   Negotiation of New Feature Use
  
       The iSCSIProtocolLevel operational text key (see 7.1.1)
       containing a value of "2" or higher MUST be negotiated to enable
       the use of features described in this RFC.
  
       Note that an operational value of "2" or higher for this key on
       an iSCSI session does not influence the SCSI level features in
       any way on that I_T nexus. An operational value of "2" or higher
       for this key permits the iSCSI-related features defined in this
       document to be used on all connections on this iSCSI session.
       SCSI level hand-shakes (e.g. commands, mode pages) eventually
       determine the existence or lack of various SAM features available
       for the I_T nexus between the two SCSI end points).  To
       summarize, negotiation of this key to "2" or higher is a
       necessary but not a sufficient condition of SAM-4 compliant
       feature usage at the SCSI protocol level.
  
       For example, an iSCSI implementation may negotiate this new key
       to "2" but respond to the new task management functions (see 6.2)
       with a "Task management function not supported" (which indicates
       a SCSI error that prevents the function from being performed).
       In contrast, if the key is negotiated to "2", an iSCSI
       implementation MUST NOT reject a task management function request
       PDU that requests one of the new task management functions (such
       a reject would report an iSCSI protocol error).
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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   5.   SCSI Commands
  
   5.1  SCSI Command Additions
  
      The format of the SCSI Command PDU is:
  
     Byte/     0       |       1       |       2       |       3       |
        /              |               |               |               |
       |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
       +---------------+---------------+---------------+---------------+
      0|.|I| 0x01      |F|R|W|. .|ATTR | PRI   | Reserved              |
       +---------------+---------------+---------------+---------------+
      4|TotalAHSLength | DataSegmentLength                             |
       +---------------+---------------+---------------+---------------+
      8| Logical Unit Number (LUN)                                     |
       +                                                               +
     12|                                                               |
       +---------------+---------------+---------------+---------------+
     16| Initiator Task Tag                                            |
       +---------------+---------------+---------------+---------------+
     20| Expected Data Transfer Length                                 |
       +---------------+---------------+---------------+---------------+
     24| CmdSN                                                         |
       +---------------+---------------+---------------+---------------+
     28| ExpStatSN                                                     |
       +---------------+---------------+---------------+---------------+
     32/ SCSI Command Descriptor Block (CDB)                           /
      +/                                                               /
       +---------------+---------------+---------------+---------------+
     48/ AHS (Optional)                                                /
       +---------------+---------------+---------------+---------------+
      x/ Header Digest (Optional)                                      /
       +---------------+---------------+---------------+---------------+
      y/ (DataSegment, Command Data) (Optional)                        /
      +/                                                               /
       +---------------+---------------+---------------+---------------+
      z/ Data Digest (Optional)                                        /
       +---------------+---------------+---------------+---------------+
  
   5.1.1 Command Priority (byte 2)
  
      The Command Priority (PRI) specifies the relative scheduling
      importance of this task in relation to other SIMPLE tasks already
      in the task set (see [SAM4]).
  
      Section 10, iSCSI PDU Formats of [RFC3720], requires that senders
      set this field to zero.  A sender MUST NOT set this field to a
      value other than zero unless the iSCSIProtocolLevel text key
  
  
  
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     defined in section Error! Reference source not found. has been
     negotiated on the session with a value of "2" or higher.
  
     This field MUST be ignored by iSCSI targets unless the
     iSCSIProtocolLevel text key with a value of "2" or higher as
     defined in section Error! Reference source not found. was
     negotiated on the session.
  
  5.2  SCSI Response Additions
  
     The format of the SCSI Response PDU is:
  
    Byte/     0       |       1       |       2       |       3       |
       /              |               |               |               |
      |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
      +---------------+---------------+---------------+---------------+
     0|.|.| 0x21      |1|. .|o|u|O|U|.| Response      | Status        |
      +---------------+---------------+---------------+---------------+
     4|TotalAHSLength | DataSegmentLength                             |
      +---------------+---------------+---------------+---------------+
     8| Status Qualifier              | Reserved                      |
      +---------------+---------------+---------------+---------------+
    12| Reserved                                                      |
      +---------------+---------------+---------------+---------------+
    16| Initiator Task Tag                                            |
      +---------------+---------------+---------------+---------------+
    20| SNACK Tag or Reserved                                         |
      +---------------+---------------+---------------+---------------+
    24| StatSN                                                        |
      +---------------+---------------+---------------+---------------+
    28| ExpCmdSN                                                      |
      +---------------+---------------+---------------+---------------+
    32| MaxCmdSN                                                      |
      +---------------+---------------+---------------+---------------+
    36| ExpDataSN or Reserved                                         |
      +---------------+---------------+---------------+---------------+
    40| Bidirectional Read Residual Count or Reserved                 |
      +---------------+---------------+---------------+---------------+
    44| Residual Count or Reserved                                    |
      +---------------+---------------+---------------+---------------+
    48| Header-Digest (Optional)                                      |
      +---------------+---------------+---------------+---------------+
      / Data Segment (Optional)                                       /
     +/                                                               /
      +---------------+---------------+---------------+---------------+
      | Data-Digest (Optional)                                        |
      +---------------+---------------+---------------+---------------+
  
  
  
  
  
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    5.2.1 Status Qualifier
  
       The Status Qualifier provides additional status information (see
       [SAM4]).
  
       As defined in Section 10, iSCSI PDU Formats of [RFC3720],
       compliant senders already set this field to zero.  Compliant
       senders MUST NOT set this field to a value other than zero unless
       the iSCSIProtocolLevel text key with a value of "2" or higher as
       defined in section 7.1.1. was negotiated on the session.
  
       This field MUST be ignored by receivers unless the
       iSCSIProtocolLevel text key with a value of "2" or higher as
       defined in section 7.1.1. was negotiated on the session.
  
  
  
    5.2.2 Data Segment - Sense and Response Data Segment
  
       Section 10.4.7 of [RFC3720] specifies that iSCSI targets MUST
       support and enable autosense.  If Status is CHECK CONDITION
       (0x02), then the Data Segment MUST contain sense data for the
       failed command.  While [RFC3720] does not make any statements
       about the state of the Data Segment when the Status is not CHECK
       CONDITION (0x02)(i.e., the Data Segment is not prohibited from
       containing sense data when the Status is not CHECK CONDITION),
       negotiation of the iSCSIProtocolLevel text key with a value of
       "2" or higher as defined in section Error! Reference source not
       found. explicitly indicates that the Data Segment MAY contain
       sense data at any time, no matter what value is set in the Status
       field.
  
    6.   Task Management Functions
  
    6.1  Existing Task Management Functions
  
       Section 10.5 of [RFC3720] defines the semantics used to request
       SCSI Task Management Functions be performed.  The following task
       management functions are defined:
  
        1 - ABORT TASK
        2 - ABORT TASK SET
        3 - CLEAR ACA
        4 - CLEAR TASK SET
        5 - LOGICAL UNIT RESET
        6 - TARGET WARM RESET
        7 - TARGET COLD RESET
        8 - TASK REASSIGN
  
  
  
  
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    6.2  Task Management Function Additions
  
       Additional task Management function codes are listed below.  For
       a more detailed description of SCSI task management, see [SAM5].
  
         9 - QUERY TASK - determines if the task identified by the
         Referenced Task Tag field is present in the task set.
  
         10 - QUERY TASK SET - determine if any task is present in the
         task set.
  
         11 - I_T NEXUS RESET - perform an I_T nexus loss function for
         the I_T nexus of each logical unit accessible through the I_T
         Nexus on which the task management function was received.
  
         12 - QUERY ASYNCHRONOUS EVENT - determine if there is a unit
         attention condition or a deferred error pending for the I_T_L
         nexus on which the task management function was received.
  
       These task management function requests MUST NOT be sent unless
       the iSCSIProtocolLevel text key with a value of "2" or higher as
       defined in section 7.1.1. was negotiated on the session.
  
       Any compliant initiator that sends any of the new task management
       functions defined in this section MUST also support all new task
       management function responses (see 6.3.1).
  
       For all of the task management functions detailed in this
       section, the Task Management function response MUST be returned
       as detailed in section 6.3 Task Management Function Response.
  
       The iSCSI target MUST ensure that no responses for the tasks
       covered by a task management function are sent to the iSCSI
       initiator after the Task Management response except for a task
       covered by a TASK REASSIGN, QUERY TASK, or QUERY TASK SET.
  
       If a QUERY TASK is issued for a task created by an immediate
       command then RefCmdSN MUST be that of the Task Management request
       itself (i.e., CmdSN and RefCmdSN are equal); otherwise RefCmdSN
       MUST be set to the CmdSN of the task to be queried (lower than
       CmdSN).
  
       At the target a QUERY TASK function MUST NOT be executed on a
       Task Management request; such a request MUST result in Task
       Management response of "Function rejected".
  
       For the I_T NEXUS RESET function, the target device MUST respond
       to the function as defined in [SAM4].  Each logical unit
       accessible via the receiving I_T NEXUS MUST behave as dictated by
  
  
  
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       the I_T nexus loss function in [SAM4] for the I_T nexus on which
       the task management function was received.  The target device
       MUST drop all connections in the session over which this function
       is recevied.  Independent of the DefaultTime2Wait and
       DefaultTime2Retain value applicable to the session over which
       this function is received, the target device MUST consider each
       participating connection in the session to have immediately timed
       out, leading to FREE state.  The resulting timeouts cause the
       session timeout event defined in [RFC3720], which in turn
       triggers the I_T nexus loss notification to the SCSI layer as
       described in [RFC3720].
  
    6.2.1 LUN field
  
       This field is required for functions that address a specific LU
       (i.e., ABORT TASK, CLEAR TASK SET, ABORT TASK SET, CLEAR ACA,
       LOGICAL UNIT RESET, QUERY TASK, QUERY TASK SET, and QUERY
       ASYNCHRONOUS EVENT) and is reserved in all others.
  
    6.2.2 Referenced Task Tag
  
       The Initiator Task Tag of the task to be aborted for the ABORT
       TASK function, reassigned for the TASK REASSIGN function, or
       queried for the QUERY TASK function.  For all other functions
       this field MUST be set to the reserved value 0xffffffff.
  
    6.2.3 RefCmdSN
  
       If a QUERY TASK is issued for a task created by an immediate
       command then RefCmdSN MUST be that of the Task Management request
       itself (i.e., CmdSN and RefCmdSN are equal).
  
       For a QUERY TASK of a task created by non-immediate command
       RefCmdSN MUST be set to the CmdSN of the task identified by the
       Referenced Task Tag field.  Targets must use this field as
       described in section 10.6.1 of [RFC3720] when the task identified
       by the Referenced Task Tag field is not in the task set.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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    6.3  Task Management Function Responses
  
     Byte/     0       |       1       |       2       |       3       |
        /              |               |               |               |
       |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
       +---------------+---------------+---------------+---------------+
      0|.|.| 0x22      |1| Reserved    | Response      | Reserved      |
       +---------------+---------------+---------------+---------------+
      4|TotalAHSLength | DataSegmentLength                             |
       +-----------------------------------------------+---------------+
      8| Additional Response Information               | Reserved      |
       +-----------------------------------------------+---------------+
     12| Reserved                                                      |
       +---------------+---------------+---------------+---------------+
     16| Initiator Task Tag                                            |
       +---------------+---------------+---------------+---------------+
     20| Reserved                                                      |
       +---------------+---------------+---------------+---------------+
     24| StatSN                                                        |
       +---------------+---------------+---------------+---------------+
     28| ExpCmdSN                                                      |
       +---------------+---------------+---------------+---------------+
     32| MaxCmdSN                                                      |
       +---------------+---------------+---------------+---------------+
     36/ Reserved                                                      /
      +/                                                               /
       +---------------+---------------+---------------+---------------+
     48| Header-Digest (Optional)                                      |
       +---------------+---------------+---------------+---------------+
  
       Section 10.6 of [RFC3720] defines the semantics used for
       responses to SCSI Task Management Functions.  The following
       responses are defined in [RFC3720]:
  
         0 - Function Complete.
         1 - Task does not exist.
         2 - LUN does not exist.
         3 - Task still allegiant.
         4 - Task allegiance reassignment not supported.
         5 - Task management function not supported.
         6 - Function authorization failed.
         255 - Function rejected.
  
       Responses to new task management functions (see 6.3.1) are listed
       below.  In addition, a new task Management response is listed
       below.  For a more detailed description of SCSI task management
       responses, see [SAM5].
  
  
  
  
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       For the functions QUERY TASK, QUERY TASK SET, I_T NEXUS RESET,
       and QUERY ASYNCHRONOUS EVENT, the target performs the requested
       Task Management function and sends a Task Management response
       back to the initiator.
  
    6.3.1 Task Management Function Response Additions
  
       The new response is listed below:
  
         7 - Function succeeded.
  
       In symbolic terms Response value 7 maps to the SCSI service
       response of FUNCTION SUCCEEDED.
  
       The task management function response of function succeeded MUST
       be supported by an initiator that sends any of the new task
       management functions (see 6.2).
  
       For the QUERY TASK function, if the specified task is in the task
       set, then the target returns a Response value of Function
       succeeded and additional response information is returned as
       specified in [SAM5].  If the specified task is not in the task
       set, then the target returns a Response value of Function
       complete.
  
       For the QUERY TASK SET function, if there is any command present
       in the task set from the specified I_T_L nexus, then the target
       returns a Response value of Function succeeded.  If there are no
       commands present in the task set from the specified I_T_L nexus,
       then the target returns a Response value of Function complete.
  
       For the I_T NEXUS RESET function, after completion of the events
       described in section 6.2 for this function, the target returns a
       Response value of Function complete.  However, because the target
       drops all connections, the Service Response (defined by [SAM4])
       for this SCSI task management function may not be reliably
       delivered to the issuing initiator port.
  
       For the QUERY ASYNCHRONOUS EVENT, if there is a unit attention
       condition or deferred error pending for the specified I_T_L
       nexus, then the target returns a Response value of Function
       succeeded and additional response information is returned as
       specified in [SAM5].  If there is no unit attention or deferred
       error pending for the specified I_T_L nexus then the target
       returns a Response value of Function complete.
  
    6.4  Task Management Requests Affecting Multiple Tasks
  
       Section 4.1 of [RFC5048] defines the notion of "affected tasks"
       in multi-task abort scenarios.  This section adds to the list
  
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       include in that section by defining the tasks affected by the I_T
       NEXUS RESET function.
  
          I_T NEXUS RESET: All outstanding tasks received on the I_T
            nexus on which the function request was received for all
            logical units accessible to the I_T nexus.
  
       Section 4.1.2 of [RFC5048] and section 4.1.3 of [RFC5048]
       identify semantics for task management functions that involve
       multi-task abort operations.  If an iSCSI implementation supports
       the I_T NEXUS RESET function, it MUST also support the protocol
       behavior as defined in those sections and follow the sequence of
       actions as described in those sections when processing the I_T
       NEXUS RESET function.
  
    7.   Login/Text Operational Text Keys
  
    7.1  New Operational Text Keys
  
    7.1.1 iSCSIProtocolLevel
  
       Use: LO
       Irrelevant when:  SessionType = Discovery
       Senders: Initiator and Target
       Scope: SW
  
       iSCSIProtocolLevel=<numerical-value-from-1-to-65535>
  
       Default is 1.
       Result function is Minimum.
  
       This key is used to negotiate the use of iSCSI features that
       require different levels of protocol support for proper
       operation.  This key is negotiated on the iSCSI session once the
       session is in full feature phase.
  
       Negotiation of the iSCSIProtocolLevel key to a value claimed by
       an RFC indicates that both negotiating parties are compliant to
       the RFC in question, and agree to support the corresponding
       semantics on that iSCSI session.  An operational value of iSCSI
       ProtocolLevel = "x" on an iSCSI session requires that the iSCSI
       protocol semantics on that iSCSI session be a logical superset of
       the capabilities in all RFCs that have claimed values of an
       iSCSIProtocolLevel less than "x".
  
       An iSCSIProtocolLevel key negotiated to "2" or higher is required
       to enable use of features defined in this RFC.
  
       If the negotiation answer is ignored by the acceptor, or the
       answer from the remote iSCSI end point is key=NotUnderstood, then
  
  
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       the features defined in this RFC, and the features defined in any
       RFC requiring a key value greater than "2" MUST NOT be used.
  
    8.   Security Considerations
  
       At the time of writing this document does not introduce any new
       security considerations other than those described in [RFC3720].
       Consequently, all the iSCSI-related security text in [RFC3723] is
       also directly applicable to this document.
  
    9.   IANA Considerations
  
       This document modifies or creates a number of iSCSI-related
       registries.  The following iSCSI-related registries are modified:
  
       1. iSCSI Task Management Functions Codes
  
         Name of the existing registry: "iSCSI TMF Codes"
  
         Additional entries:
  
         9, QUERY TASK, [RFCxxx]
  
         10, QUERY TASK SET, [RFCxxx]
  
         11, I_T NEXUS RESET, [RFCxxx]
  
         12, QUERY ASYNCHRONOUS EVENT, [RFCxxx]
  
         ---------------------------------------------------------
         RFC EDITORS NOTE: The above reference to [RFCxxx] should
         reference this RFC, and this note should be removed.
         ---------------------------------------------------------
  
       2. iSCSI Login/Text Keys
  
         Name of the existing registry: "iSCSI Text Keys"
  
         Additional entry:
  
         iSCSIProtocolLevel = "2", [RFCxxx]
         ---------------------------------------------------------
         RFC EDITORS NOTE: The above references to [RFCxxx] should
         reference this RFC, and this note should be removed.
         ---------------------------------------------------------
  
       This document creates the following iSCSI-related registries for
       IANA to manage.
  
       3. iSCSI Task Management Response Codes
  
  
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         Name of new registry: "iSCSI TMF Response Codes"
  
         Namespace details: Numerical values that can fit in 8 bits.
  
         Information that must be provided to assign a new value: An
         IESG-approved specification defining the semantics and
         interoperability requirements of the proposed new value and
         the fields to be recorded in the registry.
  
         Assignment policy:
  
         If the requested value is not already assigned, it may be
         assigned to the requester.
  
         8-254: Range reserved by iANA for assignment in this registry.
  
         Fields to record in the registry: Assigned value, Operation
         Name, and its associated RFC reference.
  
         0x0, Function complete, [RFC3720]
  
         0x1, Task does not exist, [RFC3720]
  
         0x2, LUN does not exist, [RFC3720]
  
         0x3, Task still allegiant, [RFC3720]
  
         0x4, Task allegiance reassignment not supported, [RFC3720]
  
         0x5, Task management function not supported, [RFC3720]
  
         0x6, Function authorization failed, [RFC3720]
  
         0x7, Function succeeded, [RFCxxx]
  
         255, Function rejected, [RFC3720]
  
         ------------------------------------------------------------
         RFC EDITORS NOTE: The above reference to [RFCxxx] should
         reference this RFC, and this note should be removed.
         ------------------------------------------------------------
  
         Allocation Policy:
  
         Standards Action ([IANA])
  
    10.  References
  
    10.1 Normative References
  
  
  
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       [RFC2119]  Bradner, S. "Key Words for use in RFCs to Indicate
                 Requirement Levels", BCP 14, RFC 2119, March 1997.
  
       [RFC3720]  Satran, J., Meth, K., Sapuntzakis, C., Chadalapaka,
                 M., and E. Zeidner, "Internet Small Computer Systems
                 Interface (iSCSI)", RFC 3720, April 2004.
  
       [RFC3723]  Aboba, B., Tseng, J., Walker, J., Rangan, V., and
                 Travostino, F., "Securing Block Storage Protocols
                 over IP", RFC 3723, April 2004.
  
       [RFC5048]  Chadalapaka, M., "Internet Small Computer System
                 Interface (iSCSI) Corrections and Clarifications",
                 RFC 5048, October 2007.
  
       [IANA]     Narten, T. and H. Alvestrand, "Guidelines for Writing
                 an IANA Considerations Section in RFCs", BCP 26, RFC
                 5226,May 2008.
  
       [SAM2]     T10/1157D, SCSI Architecture Model - 2 (SAM-2).
  
       [SAM4]     ISO/IEC 14776-414, SCSI Architecture Model - 4 (SAM-
                 4).
  
       [SAM5]     T10/2104D rev r05, SCSI Architecture Model - 5 (SAM-
                 5), Committee Draft.
  
    10.2 Additional Reference Sources
  
       For more information on the SCSI Architecture Model, contact the
       T10 group at http://www.t10.org.
  
    11.  Acknowledgements
  
       The Storage Maintenance (STORM) Working Group in the Transport
       Area of the IETF has been responsible for defining these
       additions to the iSCSI protocol (apart from other relevant IP
       Storage protocols).  The editor acknowledges the contributions of
       the entire working group.
  
       The following individuals directly contributed to identifying
       [RFCxxx] issues and/or suggesting resolutions to the issues
       clarified in this document: David Black, Rob Elliott.  This
       document benefited from all of these contributions.
  
         ------------------------------------------------------------
         RFC EDITORS NOTE: The above reference to [RFCxxx] should
         reference this RFC, and this note should be removed.
         ------------------------------------------------------------
  
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               Editor's Addresses
               Frederick Knight
               7301 Kit Creek Road
               P.O. Box 13917
               Research Triangle Park, NC 27709, USA
               Phone: +1-919-476-5362
               Email: knight@netapp.com
  
  
               Mallikarjun Chadalapaka
               Hewlett-Packard Company
               8000 Foothills Blvd.
               Roseville, CA 95747-5668, USA
               Phone: +1-916-785-5621
               EMail: cbm@rose.hp.com
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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