[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

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

Storage Maintenance (StorM) Working Group         Frederick Knight
Internet Draft                                              NetApp
Intended status: Standards Track                    M. Chadalapaka
Expires: February 2014                                   Microsoft
                                                       August 2013


  Internet Small Computer Systems Interface (iSCSI) SCSI Features
                               Update
                 draft-ietf-storm-iscsi-sam-09.txt

Abstract

  Internet Small Computer Systems Interface (iSCSI) is a SCSI
  transport protocol that maps the SCSI family of protocols onto
  TCP/IP. The iSCSI protocol as specified in RFCxxx (and as
  previously specified by the combination of RFC 3720 and RFC
  5048) is based on the SAM-2 (SCSI Architecture Model - 2)
  version of the SCSI family of protocols. This document
  defines enhancements to the iSCSI protocol to support certain
  additional features of the SCSI protocol that were defined in
  SAM-3, SAM-4, and SAM-5.

  This document is a companion document to RFCxxx.

     --------------------------------------------------------
     RFC EDITORS NOTE: The above two references to RFCxxx should
     reference the RFC number assigned to the draft-ietf-storm-
     iscsi-cons-xx document, and this note should be removed.
     --------------------------------------------------------

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 February, 2014.


Knight, et al.           Expires February, 2014             [Page 1]
Internet-Draft         iSCSI SCSI Features Update           August 13

Copyright Notice

   Copyright (c) 2013 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. New Feature Use............................................... 7
4.1 Negotiation of New Feature Use............................... 7
4.2 Impact on standard INQUIRY data.............................. 7
5. SCSI Commands................................................. 8
  5.1     SCSI Command Additions ................................ 8
    5.1.1     Command Priority (byte 2) ......................... 9
  5.2     SCSI Response Additions .............................. 10
    5.2.1     Status Qualifier ................................. 11
    5.2.2     Data Segment - Sense and Response Data Segment ... 11
6. Task Management Functions.................................... 12
  6.1     Task Management Function Request PDU ................. 12
  6.2     Existing Task Management Functions ................... 12
  6.3     Task Management Function Additions ................... 13
    6.3.1     LUN field ........................................ 14
    6.3.2     Referenced Task Tag .............................. 14
    6.3.3     RefCmdSN ......................................... 15
  6.4     Task Management Function Responses ................... 16
    6.4.1     Task Management Function Response PDU ............ 16
    6.4.2     Task Management Function Response Additions ...... 17
  6.5     Task Management Requests Affecting Multiple Tasks .... 18
7. Login/Text Operational Text Keys............................. 18
  7.1     New Operational Text Keys ............................ 18
    7.1.1     iSCSIProtocolLevel ............................... 18
8. Security Considerations...................................... 19
9. IANA Considerations.......................................... 19
10. References.................................................. 22
11. Acknowledgements............................................ 23




Knight, et al.           Expires February, 2014                Page 2
Internet-Draft           iSCSI SCSI Features Update           August 13


1.      Introduction

     The original iSCSI protocol [RFC3720] was built based on the
     [SAM2] model for SCSI. Several new features and capabilities
     have been added to the SCSI Architecture Model in the intervening
     years (at the time of publication of this document, SAM-5 was 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 [draft-ietf-storm-iscsi-
     cons-xx]; this document may also be used as a companion document
     to the combination of [RFC3720] and [RFC5048], although both of
     those RFCs have been obsolete by [draft-ietf-storm-iscsi-cons-
     xx].

        --------------------------------------------------------
        RFC EDITORS NOTE: The above references to [draft-ietf-storm-
        iscsi-cons-xx] should reference the RFC number assigned to
        that document, and this note should be removed.
        --------------------------------------------------------

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

     ISID     Initiator Session Identifier
     LU       Logical Unit
     PDU      Protocol Data Unit
     SAM-5    SCSI Architecture Model - 5 (see [SAM5])
     TMF      Task Management Function

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 SAM-5 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



Knight, et al.             Expires February, 2014                Page 3
Internet-Draft           iSCSI SCSI Features Update         August 13

                   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
                  Four new task management functions (QUERY TASK,
                  QUERY TASK SET, I_T NEXUS RESET, and QUERY
                  ASYNCHRONOUS EVENT have been added (see 6.3).
                  A new "function succeeded" response has been added
                  (see 6.4.2).

       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 [RFC-cons]) 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-5 terms are not necessarily equivalent, but rather,
     the iSCSI terms represent examples of the objects or classes
     described in SAM-5 as follows:

       --------------------------------------------------------
       RFC EDITORS NOTE: The above reference to [RFC-cons] should
       reference the RFC number assigned to [draft-ietf-storm-iscsi-
       cons-xx], and this note should be removed.
       --------------------------------------------------------




Knight, et al.               Expires February, 2014            Page 4
Internet-Draft        iSCSI SCSI Features Update         August 13


  +-----------------------------+---------------------------+
  | RFCxxx Terminology          | SAM-5 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        | SCSI Initiator Port       |
  | Identifier; (i.e., iSCSI    | Identifier                |
  | Node Name + ,,,i, + ISID)*1 |                           |
  +-----------------------------+---------------------------+
  | iSCSI Initiator Port Name;  | SCSI Initiator Port Name  |
  | (i.e., iSCSI Node Name +    |                           |
  | ,,,i, + ISID)*1             |                           |
  +-----------------------------+---------------------------+
  | iSCSI Target Node           | SCSI Target Device        |
  +-----------------------------+---------------------------+
  | iSCSI Target Name           | SCSI Device Name          |
  +-----------------------------+---------------------------+
  | iSCSI Target Port           | SCSI Target Port          |
  | Identifier; (i.e., iSCSI    | Identifier                |
  | Node Name + ,,,t, +         |                           |
  | Target Portal Group Tag)*1  |                           |
  +-----------------------------+---------------------------+
  | iSCSI Target Port Name;     | SCSI Target Port Name     |
  | (i.e., iSCSI Node Name +    |                           |
  | ,,,t, + Target Portal       |                           |
  | Group Tag)*1                |                           |
  +-----------------------------+---------------------------+
  | iSCSI Target Portal Group   | SCSI Target Port          |
  +-----------------------------+---------------------------+
  | iSCSI Initiator Name +      | I_T Nexus Identifier      |
  | ',i,' + ISID + iSCSI        |                           |
  | Target Name + ',t,' +       |                           |
  | Target Portal Group Tag     |                           |
  +-----------------------------+---------------------------+
  | Target Portal Group Tag     | Relative Port ID          |
  +-----------------------------+---------------------------+

  *1 The text encoding of the ISID value and the Target Portal
  Group Tag value includes an initial ,,0X or ,,0x (see [RFC-
  cons]).



Knight, et al.          Expires February, 2014              Page 5
Internet-Draft         iSCSI SCSI Features Update         August 13


     --------------------------------------------------------
     RFC EDITORS NOTE: The above reference (in row 1) to [RFCxxx]
     should reference this RFC, and this note should be removed.

     The above reference to [RFC-cons] should reference the RFC
     number assigned to [draft-ietf-storm-iscsi-cons-xx], and this
     note should be removed.
     --------------------------------------------------------

  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)                    |
+--------------------------------------------------------------------+




Knight, et al.           Expires February, 2014              Page 6
Internet-Draft            iSCSI SCSI Features Update        August 13


4.      New Feature Use

4.1     Negotiation of New Feature Use

     The iSCSIProtocolLevel operational text key (see 7.1.1)
     containing a value of "2" MUST be negotiated to enable the use of
     features described in this RFC.

     This is an iSCSI negotiation mechanism that enabled iSCSI support
     for corresponding SCSI capabilities (see [SAM5] and [SPC4]. For
     this reason, negotiation of this key to a value of "2" is
     necessary, but not sufficient for use of the SCSI capabilities
     enabled by the iSCSI features in this RFC.

     For example, an iSCSI implementation may negotiate this new key
     to "2" but respond to the new task management functions (see 6.3)
     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 (as
     such a reject would report an iSCSI protocol error).

4.2   Impact on standard INQUIRY data

     The negotiated value of the iSCSIProtocolLevel key is an
     increment from the base iSCSI version descriptor value
     (0960h)(see [SPC4]). If the SCSI device server returns an iSCSI
     version descriptor in the standard INQUIRY data, then the value
     returned in that iSCSI version descriptor MUST be set to the sum
     of the base value (0960h) plus the negotiated value of the
     iSCSIProtocolLevel key (for example, if the negotiated
     iSCSIProtocolLevel=2, then if an iSCSI version descriptor is
     returned in the standard INQUIRY data it is set to 0962h).

        --------------------------------------------------------
        RFC EDITORS NOTE: The specification text in this section
        requires corresponding changes in a SCSI standard (SPC-4 or
        SPC-5) that is developed by INCITS Technical Committee T10.
        Confirmation that these T10 changes have been made is
        necessary before publishing this draft as an RFC; the
        contacts for obtaining this confirmation are the primary
        draft author (Frederick Knight) and storm WG chair (David
        Black).
        --------------------------------------------------------




Knight, et al.             Expires February, 2014              Page 7
Internet-Draft           iSCSI SCSI Features Update         August 13


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)                                        /
  +---------------+---------------+---------------+---------------+

     The SCSI Command PDU above is duplicated from [RFC-cons] for
     reference to show the PRI field. For any field other than the
     PRI field, the text in [RFC-cons] supersedes the text in section
     5.1 of this document in the event the two documents conflict.

       --------------------------------------------------------
       RFC EDITORS NOTE: The above references to [RFC-cons] should
       reference the RFC number assigned to [draft-ietf-storm-iscsi-
       cons-xx], and this note should be removed.
       --------------------------------------------------------




Knight, et al.             Expires February, 2014              Page 8
Internet-Draft         iSCSI SCSI Features Update        August 13

5.1.1 Command Priority (byte 2)

  The Command Priority (PRI) is a four (4) bit field that specifies
  the relative scheduling importance of this command in relation to
  other commands already in the task set with SIMPLE task
  attributes(see [SAM5]).

  Section 11, iSCSI PDU Formats of [RFC-cons], 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
  defined in section 7.1.1 has been negotiated on the session with
  a value of "2".

     --------------------------------------------------------
     RFC EDITORS NOTE: The above reference to [RFC-cons] should
     reference the RFC number assigned to [draft-ietf-storm-iscsi-
     cons-xx], and this note should be removed.
     --------------------------------------------------------

  This field MUST be ignored by iSCSI targets unless the
  iSCSIProtocolLevel text key with a value of "2" as defined in
  section 7.1.1 was negotiated on the session.

  See [SAM5] for additional considerations on the use of the
  command priority field.




Knight, et al.           Expires February, 2014                Page 9
Internet-Draft         iSCSI SCSI Features Update         August 13


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)                                        |
   +---------------+---------------+---------------+---------------+

  The SCSI Response PDU above is duplicated from [RFC-cons] for
  reference to show the Status Qualifier field. For any field
  other than the Status field, the Status Qualifier field, and the
  Data Segment - Sense and Response Data Segment field, the text in
  [RFC-cons] supersedes the text in section 5.2 of this document in
  the event the two documents conflict.

      --------------------------------------------------------
      RFC EDITORS NOTE: The above references to [RFC-cons] should
      reference the RFC number assigned to [draft-ietf-storm-iscsi-
      cons-xx], and this note should be removed.
      --------------------------------------------------------

Knight, et al.           Expires February, 2014             Page 10
Internet-Draft           iSCSI SCSI Features Update      August 13


5.2.1 Status Qualifier

  The Status Qualifier provides additional status information (see
  [SAM5]).

  As defined in Section 11, iSCSI PDU Formats of [RFC-cons],
  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" as defined in
  section 7.1.1 was negotiated on the session.

     --------------------------------------------------------
     RFC EDITORS NOTE: The above reference to [RFC-cons] should
     reference the RFC number assigned to [draft-ietf-storm-iscsi-
     cons-xx], and this note should be removed.
     --------------------------------------------------------

  This field MUST be ignored by receivers unless the
  iSCSIProtocolLevel text key with a value of "2" as defined in
  section 7.1.1 was negotiated on the session.

5.2.2 Data Segment - Sense and Response Data Segment

  Section 11.4.7 of [RFC-cons] 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 [RFC-cons] 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" as defined in section 7.1.1 explicitly indicates that the
  Data Segment MAY contain sense data at any time, no matter what
  value is set in the Status field.

     --------------------------------------------------------
     RFC EDITORS NOTE: The above references to [RFC-cons] should
     reference the RFC number assigned to [draft-ietf-storm-iscsi-
     cons-xx], and this note should be removed.
     --------------------------------------------------------




Knight, et al.            Expires February, 2014           Page 11
Internet-Draft           iSCSI SCSI Features Update         August 13


6.     Task Management Functions

6.1    Task Management Function Request PDU

 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| 0x02      |1| Function    | Reserved                      |
   +---------------+---------------+---------------+---------------+
  4|TotalAHSLength | DataSegmentLength                             |
   +---------------+---------------+---------------+---------------+
  8| Logical Unit Number (LUN)                                     |
   +                                                               +
 12|                                                               |
   +---------------+---------------+---------------+---------------+
 16| Initiator Task Tag                                            |
   +---------------+---------------+---------------+---------------+
 20| Referenced Task Tag or 0xffffffff                             |
   +---------------+---------------+---------------+---------------+
 24| CmdSN                                                         |
   +---------------+---------------+---------------+---------------+
 28| ExpStatSN                                                     |
   +---------------+---------------+---------------+---------------+
 32| RefCmdSN or Reserved                                          |
   +---------------+---------------+---------------+---------------+
 36| ExpDataSN or Reserved                                         |
   +---------------+---------------+---------------+---------------+
 40| Reserved                                                      /
  +/                                                               /
   +---------------+---------------+---------------+---------------+
 48| Header-Digest (Optional)                                      |
   +---------------+---------------+---------------+---------------+

     The Task Management Function Request PDU above is duplicated from
     [RFC-cons] for reference only. [RFC-cons] supersedes the text in
     section 6.1 and 6.2 of this document in the event the two
     documents conflict.

       --------------------------------------------------------
       RFC EDITORS NOTE: The above references to [RFC-cons] should
       reference the RFC number assigned to [draft-ietf-storm-iscsi-
       cons-xx], and this note should be removed.
       --------------------------------------------------------

6.2    Existing Task Management Functions

     Section 11.5 of [RFC-cons] defines the semantics used to request
     SCSI Task Management Functions be performed. The following task
     management functions are defined:



Knight, et al.             Expires February, 2014             Page 12
Internet-Draft              iSCSI SCSI Features Update        August 13

      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

          --------------------------------------------------------
          RFC EDITORS NOTE: The above references to [RFC-cons] should
          reference the RFC number assigned to [draft-ietf-storm-iscsi-
          cons-xx], and this note should be removed.
          --------------------------------------------------------

6.3       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 command identified by the
          Referenced Task Tag field is present in the task set.

          10 - QUERY TASK SET - determine if any command is present in
          the task set for the I_T_L Nexus on which the task management
          function was received.

          11 - I_T NEXUS RESET - perform an I_T nexus loss function (see
          [SAM5]) for 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" 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 (as specified in section 6.4.2).

  For all of the task management functions detailed in this
  section, the Task Management function response MUST be returned
  as detailed in section 6.4.

  The iSCSI target MUST ensure that no responses for the commands
  covered by a task management function are sent to the iSCSI
  initiator port after the Task Management response except for a
  commands covered by a TASK REASSIGN, QUERY TASK, or QUERY TASK
  SET.


Knight, et al.                Expires February, 2014            Page 13
Internet-Draft         iSCSI SCSI Features Update        August 13


  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).

  If the connection is still active (it is not undergoing an
  implicit or explicit logout), QUERY TASK MUST be issued on the
  same connection to which the task to be queried is allegiant at
  the time the Task Management request is issued. If the
  connection is implicitly or explicitly logged out (i.e., no other
  request will be issued on the failing connection and no other
  response will be received on the failing connection), then a
  QUERY TASK function request may be issued on another connection.
  This Task Management request will then establish a new allegiance
  for the command being queried.

  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 [SAM5]. Each logical unit
  accessible via the receiving I_T NEXUS MUST behave as dictated by
  the I_T nexus loss function in [SAM5] 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 received. 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 [RFC-cons], which in turn
  triggers the I_T nexus loss notification to the SCSI layer as
  described in [RFC-cons].

     --------------------------------------------------------
     RFC EDITORS NOTE: The above references to [RFC-cons] should
     reference the RFC number assigned to [draft-ietf-storm-iscsi-
     cons-xx], and this note should be removed.
     --------------------------------------------------------

6.3.1 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.

6.3.2 Referenced Task Tag



Knight, et al.              Expires February, 2014         Page 14
Internet-Draft        iSCSI SCSI Features Update         August 13

  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.

6.3.3 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 11.6.1 of [RFC-cons] when the task
  identified by the Referenced Task Tag field is not in the task
  set.

     --------------------------------------------------------
     RFC EDITORS NOTE: The above references to [RFC-cons] should
     reference the RFC number assigned to [draft-ietf-storm-iscsi-
     cons-xx], and this note should be removed.
     --------------------------------------------------------




Knight, et al.          Expires February, 2014             Page 15
Internet-Draft           iSCSI SCSI Features Update       August 13


6.4   Task Management Function Responses

6.4.1 Task Management Function Response PDU


 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 11.6 of [RFC-cons] defines the semantics used for
  responses to SCSI Task Management Functions. The following
  responses are defined in [RFC-cons]:

      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.

  The Task Management Function Response PDU above and the list of
  task management function responses above are duplicated from
  [RFC-cons] for reference only. [RFC-cons] supersedes the text in
  section 6.4.1 of this document in the event the two documents
  conflict.


Knight, et al.             Expires February, 2014          Page 16
Internet-Draft         iSCSI SCSI Features Update        August 13


     --------------------------------------------------------
     RFC EDITORS NOTE: The above references to [RFC-cons] should
     reference the RFC number assigned to [draft-ietf-storm-iscsi-
     cons-xx], and this note should be removed.
     --------------------------------------------------------

  Responses to new task management functions (see 6.4.2) 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].

  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.

6.4.2 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 in [SAM5].

  The task management function response of "Function succeeded"
  MUST be supported by an initiator that sends any of the new task
  management functions (see 6.3).

  For the QUERY TASK function, if the specified task is in the task
  set, then the logical unit 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 logical unit 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 logical
  unit 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 logical unit returns a Response value of Function
  complete.

  For the I_T NEXUS RESET function, after completion of the events
  described in section 6.3 for this function, the logical unit
  returns a Response value of Function complete. However, because
  the target drops all connections, the Service Response (defined
  by [SAM5]) 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

Knight, et al.           Expires February, 2014            Page 17
Internet-Draft           iSCSI SCSI Features Update         August 13

     nexus, then the logical unit 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 logical unit
     returns a Response value of Function complete.

6.5    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
     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, IO
     Irrelevant when: SessionType = Discovery
     Senders: Initiator and Target
     Scope: SW

     iSCSIProtocolLevel=<numerical-value-from-0-to-31>

     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 (e.g., PDU formats,
     end node semantics) for proper operation.

     Negotiation of the iSCSIProtocolLevel key to a value
     corresponding to an RFC indicates that both negotiating parties
     are compliant to the RFC in question, and agree to support the
     corresponding PDU formats and semantics on that iSCSI session.
     Features using this key are expected to be cumulative.




Knight, et al.             Expires February, 2014             Page 18
Internet-Draft           iSCSI SCSI Features Update         August 13

     An iSCSIProtocolLevel key negotiated to "0" indicates that the
     implementation does not claim a specific iSCSI protocol level.

     An iSCSIProtocolLevel key negotiated to "1" indicates that the
     implementation claims compliance with [RFC-cons].

        --------------------------------------------------------
        RFC EDITORS NOTE: The above reference to [RFC-cons] should
        reference the RFC number assigned to [draft-ietf-storm-iscsi-
        cons-xx], and this note should be removed.
        --------------------------------------------------------

     An iSCSIProtocolLevel key negotiated to "2" 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
     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

     Command priorities are relative values, not absolute values (see
     [SAM5] and affect collections of commands, not necessarily
     individual commands (see [SAM5]); if command priority is
     supported, it should be implemented in a fashion that avoids
     unwanted reduction or denial of service.

     All the iSCSI-related security text in [RFC3723] and the security
     text in [RFC-cons] is also directly applicable to this document.

        --------------------------------------------------------
        RFC EDITORS NOTE: The above reference to [RFC-cons] should
        reference the RFC number assigned to [draft-ietf-storm-iscsi-
        cons-xx], and this note should be removed.
        --------------------------------------------------------


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 Task Management Function
        Codes"

        Additional entries:

        9, QUERY TASK, [RFCxxx]


Knight, et al.                Expires February, 2014          Page 19
Internet-Draft        iSCSI SCSI Features Update         August 13

     10, QUERY TASK SET, [RFCxxx]

     11, I_T NEXUS RESET, [RFCxxx]

     12, QUERY ASYNCHRONOUS EVENT, [RFCxxx]

     13-127, Unassigned, [RFCxxx]

     ---------------------------------------------------------
     RFC EDITORS NOTE: The above reference to [RFCxxx] should
     reference this RFC, and this note should be removed. The last
     entry (values 13-127 in the above list) should replace the
     existing entry for the "Unassigned" values.
     ---------------------------------------------------------

  2. iSCSI Login/Text Keys

     Name of the existing registry: "iSCSI Login/Text Keys"

     Fields to record in the registry: Assigned value and its
     associated RFC reference:

     iSCSIProtocolLevel, [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 Protocol Level

     Name of new registry: "iSCSI Protocol Level"

     Namespace details: Numerical values from 0 to 31

     Information that must be provided to assign a new value: An
     IESG-approved standards track specification defining the
     semantics and interoperability requirements of the proposed
     new value and the fields to be recorded in the registry.

     Assignment policy:

     The assignments of these values must be coordinated with the
     INCITS T10 committee; therefore review by an expert that
     maintains an association with that committee is required prior
     to IESG approval of the associated specification. After
     creation of the registry, values are to be assigned
     sequentially (for example, any value greater than 4 will not
     be assigned until after the value 4 has been assigned).


Knight, et al.            Expires February, 2014              Page 20
Internet-Draft          iSCSI SCSI Features Update          August 13


     Special care must be taken in the assignment of new values in
     this registry. Compatibility and interoperability will be
     adversely impacted if proper care is not exercised. Features
     using this key are expected to be cumulative. For example,
     since this draft explicitly lists only value 2 for the
     features listed in this draft, it is expected that a new RFC
     assigning value 3 will also have the features listed in this
     RFC and therefore such an RFC is expected to either revise or
     replace this RFC. Assignments that do not follow this policy
     should be reviewed and approved by the INCITS T10 committee.

     3-31: range available to IANA for assignment in this registry.

     Fields to record in the registry: Assigned value, description,
     and its associated RFC reference.

     0, No version claimed, [RFCxxx]

     1, RFC-cons, [RFCxxx]

     2, RFCxxx, [RFCxxx]

     3-31, Unassigned

     ---------------------------------------------------------
     RFC EDITORS NOTE: The above references to [RFCxxx] should
     reference this RFC, and this note should be removed. The
     above reference to RFC-cons should be replaced with the name
     of the [draft-ietf-storm-iscsi-cons-xx] document, and this
     note should be removed. All associated RFC references are to
     this document; even the reference for value 1. The
     description for value 1 however contains the RFC-cons name but
     should not have [] around the description (it is a description
     not a formal reference). The description for value 2 is the
     name of this RFC but should not contain the [] (again, a
     description not a formal reference). This note should be
     removed.
     ---------------------------------------------------------

     Allocation Policy:

     Expert review ([IANA]) and Standards Action ([IANA])

  4. iSCSI Task Management Function Response Codes

     Name of new registry: "iSCSI Task Management Function Response
     Codes"

     Namespace details: Numerical values that can fit in 8 bits.




Knight, et al.            Expires February, 2014             Page 21
Internet-Draft             iSCSI SCSI Features Update      August 13

       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 available to IANA for assignment in this
       registry.

       Fields to record in the registry: Assigned value, Operation
       Name, and its associated RFC reference.

       0, Function complete, [RFC-cons]

       1, Task does not exist, [RFC-cons]

       2, LUN does not exist, [RFC-cons]

       3, Task still allegiant, [RFC-cons]

       4, Task allegiance reassignment not supported, [RFC-cons]

       5, Task management function not supported, [RFC-cons]

       6, Function authorization failed, [RFC-cons]

       7, Function succeeded, [RFCxxx]

       8-254, Unassigned

       255, Function rejected, [RFC-cons]

       ------------------------------------------------------------
       RFC EDITORS NOTE: The above reference to [RFCxxx] should
       reference this RFC, and this note should be removed.

       The above references to [RFC-cons] should reference the
       [draft-ietf-storm-iscsi-cons-xx] document, and this note
       should be removed.
       ------------------------------------------------------------

       Allocation Policy:

       Standards Action ([IANA])

10.    References

10.1   Normative References


Knight, et al.              Expires February, 2014             Page 22
Internet-Draft            iSCSI SCSI Features Update        August 13

  [RFC2119]      Bradner, S. "Key Words for use in RFCs to Indicate
                 Requirement Levels", BCP 14, RFC 2119, March 1997.

  [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.

  [draft-ietf-storm-iscsi-cons-xx]   Chadalapaka, M., Satran, J.,
              Kalman, M., "iSCSI Protocol (consolidated)", RFC xxx,
              Date 2013.

       ------------------------------------------------------------
       RFC EDITORS NOTE: The above references to [draft-ietf-storm-
       iscsi-cons-xx] and RFC xxx should reference the RFC number
       assigned to that draft, and this note should be removed.
       ------------------------------------------------------------

  [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).

  [SAM5]         T10/2104D rev r04, SCSI Architecture Model - 5 (SAM-
                 5), Committee Draft.

  [SPC4]         T10/1731D rev r36, SCSI Primary Commands - 4 (SPC-4),
                 Committee Draft.

10.2   Informative References

  [RFC3720]      Satran, J., Meth, K., Sapuntzakis, C., Chadalapaka,
                 M., and E. Zeidner, "Internet Small Computer Systems
                 Interface (iSCSI)", RFC 3720, April 2004.

10.3   Additional Reference Sources

  For more information on the SCSI Architecture Model and SCSI
  Primary Commands - 4, contact the INCITS T10 Technical Committee
  for SCSI Storage Interfaces 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 and other IETF reviewers.


Knight, et al.             Expires February, 2014             Page 23
Internet-Draft          iSCSI SCSI Features Update       August 13

  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.
     ------------------------------------------------------------


  Author'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
  Microsoft
  One Microsoft Way
  Redmond, WA 98052 USA
  Email: cbm@chadalapaka.com




Knight, et al.           Expires February, 2014            Page 24


Html markup produced by rfcmarkup 1.107, available from http://tools.ietf.org/tools/rfcmarkup/