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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Storage Maintenance (StorM) Working Group Frederick Knight 2 Internet Draft NetApp 3 Intended status: Standards Track M. Chadalapaka 4 Expires: January 2013 Microsoft 5 July 2012 7 Internet Small Computer Systems Interface (iSCSI) SCSI Features 8 Update 9 draft-ietf-storm-iscsi-sam-06.txt 11 Abstract 13 Internet Small Computer Systems Interface (iSCSI) is a SCSI 14 transport protocol that maps the SCSI family of protocols onto 15 TCP/IP. The iSCSI protocol as specified in [draft-ietf-storm- 16 iscsi-cons-xx] (and as previously specified by the combination 17 of RFC 3720 and RFC 5048) is based on the SAM-2 (SCSI 18 Architecture Model - 2) version of the SCSI family of 19 protocols. This document defines enhancements to the iSCSI 20 protocol to support certain additional features of the SCSI 21 protocol that were defined in SAM-3, SAM-4, and SAM-5. 23 This document is a companion document to [draft-ietf-storm- 24 iscsi-cons-xx]. 26 -------------------------------------------------------- 27 RFC EDITORS NOTE: The above references to [draft-ietf-storm- 28 iscsi-cons-xx] should reference the RFC number assigned to 29 that document, and this note should be removed. 30 -------------------------------------------------------- 32 Status of this Memo 34 This Internet-Draft is submitted to IETF in full conformance with 35 the provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF), its areas, and its working groups. Note that 39 other groups may also distribute working documents as Internet- 40 Drafts. 42 Internet-Drafts are draft documents valid for a maximum of six 43 months and may be updated, replaced, or obsoleted by other 44 documents at any time. It is inappropriate to use Internet- 45 Drafts as reference material or to cite them other than as "work 46 in progress." 48 The list of current Internet-Drafts can be accessed at 49 http://www.ietf.org/1id-abstracts.html. 51 The list of Internet-Draft Shadow Directories can be accessed at 52 http://www.ietf.org/shadow.html. 54 This Internet-Draft will expire January, 2013. 56 Copyright Notice 58 Copyright (c) 2012 IETF Trust and the persons identified as the 59 document authors. All rights reserved. 61 This document is subject to BCP 78 and the IETF Trust's Legal 62 Provisions Relating to IETF Documents 63 (http://trustee.ietf.org/license-info) in effect on the date of 64 publication of this document. Please review these documents 65 carefully, as they describe your rights and restrictions with 66 respect to this document. Code Components extracted from this 67 document must include Simplified BSD License text as described in 68 Section 4.e of the Trust Legal Provisions and are provided 69 without warranty as described in the Simplified BSD License. 71 Table of Contents 73 1. Introduction.................................................. 3 74 2. Definitions, Acronyms, and Document Summary................... 3 75 2.1 Definitions ............................................ 3 76 2.2 Acronyms ............................................... 3 77 2.3 New Semantics .......................................... 3 78 3. Terminology Mapping............................................ 4 79 4. New Feature Use................................................ 7 80 4.1 Negotiation of New Feature Use................................ 7 81 4.2 Impact on standard INQUIRY data............................... 7 82 5. SCSI Commands.................................................. 8 83 5.1 SCSI Command Additions ................................. 8 84 5.1.1 Command Priority (byte 2) .......................... 8 85 5.2 SCSI Response Additions ................................ 9 86 5.2.1 Status Qualifier .................................. 10 87 5.2.2 Data Segment - Sense and Response Data Segment .... 10 88 6. Task Management Functions..................................... 10 89 6.1 Existing Task Management Functions .................... 10 90 6.2 Task Management Function Additions .................... 10 91 6.2.1 LUN field ......................................... 12 92 6.2.2 Referenced Task Tag ............................... 12 93 6.2.3 RefCmdSN .......................................... 12 94 6.3 Task Management Function Responses .................... 13 95 6.3.1 Task Management Function Response Additions ....... 14 96 6.4 Task Management Requests Affecting Multiple Tasks ..... 14 97 7. Login/Text Operational Text Keys.............................. 15 98 7.1 New Operational Text Keys ............................. 15 99 7.1.1 iSCSIProtocolLevel ................................ 15 100 8. Security Considerations....................................... 16 101 9. IANA Considerations........................................... 16 102 10. References................................................... 18 103 11. Acknowledgements............................................. 19 104 1. Introduction 106 The original iSCSI protocol [RFC3720] was built based on the 107 [SAM2] model for SCSI. Several new features and capabilities 108 have been added to the SCSI Architecture Model in the intervening 109 years (at the time of publication of this document, SAM-5 was the 110 current version of the SCSI Architecture Model). This document 111 is not a complete revision of [RFC3720]. Instead, this document 112 is intended as a companion document to [draft-ietf-storm-iscsi- 113 cons-xx]; this document may also be used as a companion document 114 to the combination of [RFC3720] and [RFC5048], although both of 115 those RFCs have been obsolete by [draft-ietf-storm-iscsi-cons- 116 xx]. 118 -------------------------------------------------------- 119 RFC EDITORS NOTE: The above references to [draft-ietf-storm- 120 iscsi-cons-xx] should reference the RFC number assigned to 121 that document, and this note should be removed. 122 -------------------------------------------------------- 124 2. Definitions, Acronyms, and Document Summary 126 2.1 Definitions 128 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL 129 NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" 130 in this document are to be interpreted as described in 131 [RFC2119]. 133 2.2 Acronyms 135 ISID Initiator Session Identifier 136 LU Logical Unit 137 PDU Protocol Data Unit 138 SAM-4 SCSI Architecture Model - 4 (see [SAM4]) 139 SAM-5 SCSI Architecture Model - 5 (see [SAM5]) 140 TMF Task Management Function 142 2.3 New Semantics 144 This document specifies new iSCSI semantics. This section 145 summarizes the contents of the document. 147 Section 3: The mapping of iSCSI objects to SAM-5 objects 148 The iSCSI node may contain both initiator and 149 target capabilities. 151 Section 4: The protocol used to negotiate the use of the new 152 capabilities described in this document. 154 Section 5: New Command operations 155 The PRI field for SCSI command priority has been 156 added to the SCSI command PDU (see 5.1.1). 157 The Status Qualifier field has been added to the 158 SCSI response PDU (see 5.2.1). 159 Sense data may be returned (via autosense) for any 160 SCSI status, not just CHECK CONDITION (see 5.2.2). 162 Section 6: New Task Management Functions 163 Four new task management functions (QUERY TASK, 164 QUERY TASK SET, I_T NEXUS RESET, and QUERY 165 ASYNCHRONOUS EVENT have been added (see 6.2). 166 A new "function succeeded" response has been added 167 (see 6.3.1). 169 Section 7: New Negotiation key 170 A new negotiation key has been added to enable the 171 use of the new features in section 5 and section 6. 173 3. Terminology Mapping 175 The iSCSI model (defined in [RFC3720]) uses different terminology 176 than the SCSI Architecture Model. In some cases, iSCSI uses 177 multiple terms to describe what in the SCSI Architecture Model is 178 described with a single term. The iSCSI terms and SAM-5 terms 179 are not necessarily equivalent, but rather, the iSCSI terms 180 represent examples of the objects or classes described in SAM-5 181 as follows: 183 +-----------------------------+---------------------------+ 184 | RFCxxx Terminology | SAM-5 Terminology | 185 +-----------------------------+---------------------------+ 186 | Network Entity | none | 187 +-----------------------------+---------------------------+ 188 | iSCSI Node | SCSI Device | 189 +-----------------------------+---------------------------+ 190 | iSCSI Name | SCSI Device Name | 191 +-----------------------------+---------------------------+ 192 | iSCSI Node Name | SCSI Device Name | 193 +-----------------------------+---------------------------+ 194 | iSCSI Initiator Node | SCSI Initiator Device | 195 +-----------------------------+---------------------------+ 196 | iSCSI Initiator Name | SCSI Device Name | 197 +-----------------------------+---------------------------+ 198 | iSCSI Initiator Port | SCSI Initiator Port | 199 | Identifier; (i.e., iSCSI | Identifier | 200 | Node Name + ,,,i, + ISID)*1| | 201 +-----------------------------+---------------------------+ 202 | iSCSI Initiator Port Name; | SCSI Initiator Port Name | 203 | (i.e., iSCSI Node Name + | | 204 | ,,,i, + ISID)*1 | | 205 +-----------------------------+---------------------------+ 206 | iSCSI Target Node | SCSI Target Device | 207 +-----------------------------+---------------------------+ 208 | iSCSI Target Name | SCSI Device Name | 209 +-----------------------------+---------------------------+ 210 | iSCSI Target Port | SCSI Target Port | 211 | Identifier; (i.e., iSCSI | Identifier | 212 | Node Name + ,,,t, + | | 213 | Target Portal Group Tag)*1 | | 214 +-----------------------------+---------------------------+ 215 | iSCSI Target Port Name; | SCSI Target Port Name | 216 | (i.e., iSCSI Node Name + | | 217 | ,,,t, + Target Portal | | 218 | Group Tag)*1 | | 219 +-----------------------------+---------------------------+ 220 | iSCSI Target Portal Group | SCSI Target Port | 221 +-----------------------------+---------------------------+ 222 | iSCSI Initiator Name + | I_T Nexus Identifier | 223 | ',i,' + ISID + iSCSI | | 224 | Target Name + ',t,' + | | 225 | Target Portal Group Tag | | 226 +-----------------------------+---------------------------+ 227 | Target Portal Group Tag | Relative Port ID | 228 +-----------------------------+---------------------------+ 230 *1 The text encoding of the ISID value and the Target Portal 231 Group Tag value includes an initial ,,0X or ,,0x (see [RFC3720]). 233 -------------------------------------------------------- 234 RFC EDITORS NOTE: The above reference (in row 1) to [RFCxxx] 235 should reference this RFC, and this note should be removed. 236 -------------------------------------------------------- 238 The following diagram shows an example of a combination target 239 device and initiator device. Such a configuration may exist in a 240 target device that implements a SCSI Copy Manager. This example 241 shows how a session that shares Network Portals within a Portal 242 Group may be established (see Target Portal Group 1). In 243 addition, this example shows the Initiator using a different 244 Portal Group than the Target Portal Group, but the Initiator 245 Portal group sharing Network Portal A with the Target Portal 246 Group. 248 ----------------------------IP Network--------------------- 249 | | | 250 +----|---------------|-------+ +----|------------+ 251 | +----------+ +----------+ | | +----------+ | 252 | | Network | | Network | | | | Network | | 253 | | Portal A | | Portal B | | | | Portal A | | 254 | +----------+ +----------+ | | +----------+ | 255 | | Target | | | | Initiator | 256 | | Portal | | | | Portal | 257 | | Group 1 | | | | Group 2 | 258 +----|---------------|-------+ +----|------------+ 259 | | | 260 +----------|---------------|--------------------|--------------------+ 261 | +--------|---------------|----+ +-------------|------------------+ | 262 | |+-------|---------------|---+| |+------------|-----------------+| | 263 | ||iSCSI Session (Target side)|| ||iSCSI Session (Initiator side)|| | 264 | || || || || | 265 | || (TSIH = 56) || || (SSID = 48) || | 266 | |+---------------------------+| |+------------------------------+| | 267 | | | | | | 268 | | iSCSI Target Node | | iSCSI Initiator Node | | 269 | +-----------------------------+ +--------------------------------+ | 270 | iSCSI Node | 271 | (within Network Entity, not shown) | 272 +--------------------------------------------------------------------+ 273 4. New Feature Use 275 4.1 Negotiation of New Feature Use 277 The iSCSIProtocolLevel operational text key (see 7.1.1) 278 containing a value of "2" or higher MUST be negotiated to enable 279 the use of features described in this RFC. 281 Note that an operational value of "2" or higher for this key on 282 an iSCSI session does not influence the SCSI level features in 283 any way on that I_T nexus. An operational value of "2" or higher 284 for this key permits the iSCSI-related features defined in this 285 document to be used on all connections on this iSCSI session. 286 SCSI level hand-shakes (e.g. commands, mode pages) eventually 287 determine the existence or lack of various SAM-5 features 288 available for the I_T nexus between the two SCSI end points). To 289 summarize, negotiation of this key to "2" or higher is a 290 necessary but not a sufficient condition of SAM-5 compliant 291 feature usage at the SCSI protocol level. 293 For example, an iSCSI implementation may negotiate this new key 294 to "2" but respond to the new task management functions (see 6.2) 295 with a "Task management function not supported" (which indicates 296 a SCSI error that prevents the function from being performed). 297 In contrast, if the key is negotiated to "2", an iSCSI 298 implementation MUST NOT reject a task management function request 299 PDU that requests one of the new task management functions (such 300 a reject would report an iSCSI protocol error). 302 4.2 Impact on standard INQUIRY data 304 The negotiated value of the iSCSIProtocolLevel key is an 305 increment from the base iSCSI version descriptor value 306 (0960h)(see [SPC4]). If the SCSI device server returns an iSCSI 307 version descriptor in the standard INQUIRY data, then the value 308 returned in that iSCSI version descriptor MUST be set to the sum 309 of the base value (0960h) plus the negotiated value of the 310 iSCSIProtocolLevel key (for example, if the negotiated 311 iSCSIProtocolLevel=2, then if an iSCSI version descriptor is 312 returned in the standard INQUIRY data it is set to 0962h). 314 5. SCSI Commands 316 5.1 SCSI Command Additions 318 The format of the SCSI Command PDU is: 320 Byte/ 0 | 1 | 2 | 3 | 321 / | | | | 322 |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| 323 +---------------+---------------+---------------+---------------+ 324 0|.|I| 0x01 |F|R|W|. .|ATTR | PRI | Reserved | 325 +---------------+---------------+---------------+---------------+ 326 4|TotalAHSLength | DataSegmentLength | 327 +---------------+---------------+---------------+---------------+ 328 8| Logical Unit Number (LUN) | 329 + + 330 12| | 331 +---------------+---------------+---------------+---------------+ 332 16| Initiator Task Tag | 333 +---------------+---------------+---------------+---------------+ 334 20| Expected Data Transfer Length | 335 +---------------+---------------+---------------+---------------+ 336 24| CmdSN | 337 +---------------+---------------+---------------+---------------+ 338 28| ExpStatSN | 339 +---------------+---------------+---------------+---------------+ 340 32/ SCSI Command Descriptor Block (CDB) / 341 +/ / 342 +---------------+---------------+---------------+---------------+ 343 48/ AHS (Optional) / 344 +---------------+---------------+---------------+---------------+ 345 x/ Header Digest (Optional) / 346 +---------------+---------------+---------------+---------------+ 347 y/ (DataSegment, Command Data) (Optional) / 348 +/ / 349 +---------------+---------------+---------------+---------------+ 350 z/ Data Digest (Optional) / 351 +---------------+---------------+---------------+---------------+ 353 5.1.1 Command Priority (byte 2) 355 The Command Priority (PRI) specifies the relative scheduling 356 importance of this task in relation to other SIMPLE tasks already 357 in the task set (see [SAM4]). 359 Section 10, iSCSI PDU Formats of [RFC3720], requires that senders 360 set this field to zero. A sender MUST NOT set this field to a 361 value other than zero unless the iSCSIProtocolLevel text key 362 defined in section 7.1.1 has been negotiated on the session with 363 a value of "2" or higher. 365 This field MUST be ignored by iSCSI targets unless the 366 iSCSIProtocolLevel text key with a value of "2" or higher as 367 defined in section 7.1.1 was negotiated on the session. 369 5.2 SCSI Response Additions 371 The format of the SCSI Response PDU is: 373 Byte/ 0 | 1 | 2 | 3 | 374 / | | | | 375 |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| 376 +---------------+---------------+---------------+---------------+ 377 0|.|.| 0x21 |1|. .|o|u|O|U|.| Response | Status | 378 +---------------+---------------+---------------+---------------+ 379 4|TotalAHSLength | DataSegmentLength | 380 +---------------+---------------+---------------+---------------+ 381 8| Status Qualifier | Reserved | 382 +---------------+---------------+---------------+---------------+ 383 12| Reserved | 384 +---------------+---------------+---------------+---------------+ 385 16| Initiator Task Tag | 386 +---------------+---------------+---------------+---------------+ 387 20| SNACK Tag or Reserved | 388 +---------------+---------------+---------------+---------------+ 389 24| StatSN | 390 +---------------+---------------+---------------+---------------+ 391 28| ExpCmdSN | 392 +---------------+---------------+---------------+---------------+ 393 32| MaxCmdSN | 394 +---------------+---------------+---------------+---------------+ 395 36| ExpDataSN or Reserved | 396 +---------------+---------------+---------------+---------------+ 397 40| Bidirectional Read Residual Count or Reserved | 398 +---------------+---------------+---------------+---------------+ 399 44| Residual Count or Reserved | 400 +---------------+---------------+---------------+---------------+ 401 48| Header-Digest (Optional) | 402 +---------------+---------------+---------------+---------------+ 403 / Data Segment (Optional) / 404 +/ / 405 +---------------+---------------+---------------+---------------+ 406 | Data-Digest (Optional) | 407 +---------------+---------------+---------------+---------------+ 409 5.2.1 Status Qualifier 411 The Status Qualifier provides additional status information (see 412 [SAM4]). 414 As defined in Section 10, iSCSI PDU Formats of [RFC3720], 415 compliant senders already set this field to zero. Compliant 416 senders MUST NOT set this field to a value other than zero unless 417 the iSCSIProtocolLevel text key with a value of "2" or higher as 418 defined in section 7.1.1 was negotiated on the session. 420 This field MUST be ignored by receivers unless the 421 iSCSIProtocolLevel text key with a value of "2" or higher as 422 defined in section 7.1.1 was negotiated on the session. 424 5.2.2 Data Segment - Sense and Response Data Segment 426 Section 10.4.7 of [RFC3720] specifies that iSCSI targets MUST 427 support and enable autosense. If Status is CHECK CONDITION 428 (0x02), then the Data Segment MUST contain sense data for the 429 failed command. While [RFC3720] does not make any statements 430 about the state of the Data Segment when the Status is not CHECK 431 CONDITION (0x02)(i.e., the Data Segment is not prohibited from 432 containing sense data when the Status is not CHECK CONDITION), 433 negotiation of the iSCSIProtocolLevel text key with a value of 434 "2" or higher as defined in section 7.1.1 explicitly indicates 435 that the Data Segment MAY contain sense data at any time, no 436 matter what value is set in the Status field. 438 6. Task Management Functions 440 6.1 Existing Task Management Functions 442 Section 10.5 of [RFC3720] defines the semantics used to request 443 SCSI Task Management Functions be performed. The following task 444 management functions are defined: 446 1 - ABORT TASK 447 2 - ABORT TASK SET 448 3 - CLEAR ACA 449 4 - CLEAR TASK SET 450 5 - LOGICAL UNIT RESET 451 6 - TARGET WARM RESET 452 7 - TARGET COLD RESET 453 8 - TASK REASSIGN 455 6.2 Task Management Function Additions 457 Additional task Management function codes are listed below. For 458 a more detailed description of SCSI task management, see [SAM5]. 460 9 - QUERY TASK - determines if the command identified by the 461 Referenced Task Tag field is present in the task set. 463 10 - QUERY TASK SET - determine if any command is present in 464 the task set for the I_T_L Nexus on which the task management 465 function was received. 467 11 - I_T NEXUS RESET - perform an I_T nexus loss function (see 468 [SAM5]) for the I_T nexus on which the task management 469 function was received. 471 12 - QUERY ASYNCHRONOUS EVENT - determine if there is a unit 472 attention condition or a deferred error pending for the I_T_L 473 nexus on which the task management function was received. 475 These task management function requests MUST NOT be sent unless 476 the iSCSIProtocolLevel text key with a value of "2" or higher as 477 defined in section 7.1.1 was negotiated on the session. 479 Any compliant initiator that sends any of the new task management 480 functions defined in this section MUST also support all new task 481 management function responses (as specified in section 6.3.1). 483 For all of the task management functions detailed in this 484 section, the Task Management function response MUST be returned 485 as detailed in section 6.3 Task Management Function Response. 487 The iSCSI target MUST ensure that no responses for the commands 488 covered by a task management function are sent to the iSCSI 489 initiator port after the Task Management response except for a 490 commands covered by a TASK REASSIGN, QUERY TASK, or QUERY TASK 491 SET. 493 If a QUERY TASK is issued for a task created by an immediate 494 command then RefCmdSN MUST be that of the Task Management request 495 itself (i.e., CmdSN and RefCmdSN are equal); otherwise RefCmdSN 496 MUST be set to the CmdSN of the task to be queried (lower than 497 CmdSN). 499 If the connection is still active (it is not undergoing an 500 implicit or explicit logout), QUERY TASK MUST be issued on the 501 same connection to which the task to be queried is allegiant at 502 the time the Task Management request is issued. If the 503 connection is implicitly or explicitly logged out (i.e., no other 504 request will be issued on the failing connection and no other 505 response will be received on the failing connection), then a 506 QUERY TASK function request may be issued on another connection. 507 This Task Management request will then establish a new allegiance 508 for the command being queried. 510 At the target a QUERY TASK function MUST NOT be executed on a 511 Task Management request; such a request MUST result in Task 512 Management response of "Function rejected". 514 For the I_T NEXUS RESET function, the target device MUST respond 515 to the function as defined in [SAM4]. Each logical unit 516 accessible via the receiving I_T NEXUS MUST behave as dictated by 517 the I_T nexus loss function in [SAM4] for the I_T nexus on which 518 the task management function was received. The target device 519 MUST drop all connections in the session over which this function 520 is received. Independent of the DefaultTime2Wait and 521 DefaultTime2Retain value applicable to the session over which 522 this function is received, the target device MUST consider each 523 participating connection in the session to have immediately timed 524 out, leading to FREE state. The resulting timeouts cause the 525 session timeout event defined in [RFC3720], which in turn 526 triggers the I_T nexus loss notification to the SCSI layer as 527 described in [RFC3720]. 529 6.2.1 LUN field 531 This field is required for functions that address a specific LU 532 (i.e., ABORT TASK, CLEAR TASK SET, ABORT TASK SET, CLEAR ACA, 533 LOGICAL UNIT RESET, QUERY TASK, QUERY TASK SET, and QUERY 534 ASYNCHRONOUS EVENT) and is reserved in all others. 536 6.2.2 Referenced Task Tag 538 The Initiator Task Tag of the task to be aborted for the ABORT 539 TASK function, reassigned for the TASK REASSIGN function, or 540 queried for the QUERY TASK function. For all other functions 541 this field MUST be set to the reserved value 0xffffffff. 543 6.2.3 RefCmdSN 545 If a QUERY TASK is issued for a task created by an immediate 546 command then RefCmdSN MUST be that of the Task Management request 547 itself (i.e., CmdSN and RefCmdSN are equal). 549 For a QUERY TASK of a task created by non-immediate command 550 RefCmdSN MUST be set to the CmdSN of the task identified by the 551 Referenced Task Tag field. Targets must use this field as 552 described in section 10.6.1 of [RFC3720] when the task identified 553 by the Referenced Task Tag field is not in the task set. 555 6.3 Task Management Function Responses 557 Byte/ 0 | 1 | 2 | 3 | 558 / | | | | 559 |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| 560 +---------------+---------------+---------------+---------------+ 561 0|.|.| 0x22 |1| Reserved | Response | Reserved | 562 +---------------+---------------+---------------+---------------+ 563 4|TotalAHSLength | DataSegmentLength | 564 +-----------------------------------------------+---------------+ 565 8| Additional Response Information | Reserved | 566 +-----------------------------------------------+---------------+ 567 12| Reserved | 568 +---------------+---------------+---------------+---------------+ 569 16| Initiator Task Tag | 570 +---------------+---------------+---------------+---------------+ 571 20| Reserved | 572 +---------------+---------------+---------------+---------------+ 573 24| StatSN | 574 +---------------+---------------+---------------+---------------+ 575 28| ExpCmdSN | 576 +---------------+---------------+---------------+---------------+ 577 32| MaxCmdSN | 578 +---------------+---------------+---------------+---------------+ 579 36/ Reserved / 580 +/ / 581 +---------------+---------------+---------------+---------------+ 582 48| Header-Digest (Optional) | 583 +---------------+---------------+---------------+---------------+ 585 Section 10.6 of [RFC3720] defines the semantics used for 586 responses to SCSI Task Management Functions. The following 587 responses are defined in [RFC3720]: 589 0 - Function Complete. 590 1 - Task does not exist. 591 2 - LUN does not exist. 592 3 - Task still allegiant. 593 4 - Task allegiance reassignment not supported. 594 5 - Task management function not supported. 595 6 - Function authorization failed. 596 255 - Function rejected. 598 Responses to new task management functions (see 6.3.1) are listed 599 below. In addition, a new task Management response is listed 600 below. For a more detailed description of SCSI task management 601 responses, see [SAM5]. 603 For the functions QUERY TASK, QUERY TASK SET, I_T NEXUS RESET, 604 and QUERY ASYNCHRONOUS EVENT, the target performs the requested 605 Task Management function and sends a Task Management response 606 back to the initiator. 608 6.3.1 Task Management Function Response Additions 610 The new response is listed below: 612 7 - Function succeeded. 614 In symbolic terms Response value 7 maps to the SCSI service 615 response of FUNCTION SUCCEEDED in [SAM4]. 617 The task management function response of "Function succeeded" 618 MUST be supported by an initiator that sends any of the new task 619 management functions (see 6.2). 621 For the QUERY TASK function, if the specified task is in the task 622 set, then the logical unit returns a Response value of Function 623 succeeded and additional response information is returned as 624 specified in [SAM5]. If the specified task is not in the task 625 set, then the logical unit returns a Response value of Function 626 complete. 628 For the QUERY TASK SET function, if there is any command present 629 in the task set from the specified I_T_L nexus, then the logical 630 unit returns a Response value of Function succeeded. If there 631 are no commands present in the task set from the specified I_T_L 632 nexus, then the logical unit returns a Response value of Function 633 complete. 635 For the I_T NEXUS RESET function, after completion of the events 636 described in section 6.2 for this function, the logical unit 637 returns a Response value of Function complete. However, because 638 the target drops all connections, the Service Response (defined 639 by [SAM4]) for this SCSI task management function may not be 640 reliably delivered to the issuing initiator port. 642 For the QUERY ASYNCHRONOUS EVENT, if there is a unit attention 643 condition or deferred error pending for the specified I_T_L 644 nexus, then the logical unit returns a Response value of Function 645 succeeded and additional response information is returned as 646 specified in [SAM5]. If there is no unit attention or deferred 647 error pending for the specified I_T_L nexus then the logical unit 648 returns a Response value of Function complete. 650 6.4 Task Management Requests Affecting Multiple Tasks 652 Section 4.1 of [RFC5048] defines the notion of "affected tasks" 653 in multi-task abort scenarios. This section adds to the list 654 include in that section by defining the tasks affected by the I_T 655 NEXUS RESET function. 657 I_T NEXUS RESET: All outstanding tasks received on the I_T 658 nexus on which the function request was received for all 659 logical units accessible to the I_T nexus. 661 Section 4.1.2 of [RFC5048] and section 4.1.3 of [RFC5048] 662 identify semantics for task management functions that involve 663 multi-task abort operations. If an iSCSI implementation supports 664 the I_T NEXUS RESET function, it MUST also support the protocol 665 behavior as defined in those sections and follow the sequence of 666 actions as described in those sections when processing the I_T 667 NEXUS RESET function. 669 7. Login/Text Operational Text Keys 671 7.1 New Operational Text Keys 673 7.1.1 iSCSIProtocolLevel 675 Use: LO, IO 676 Irrelevant when: SessionType = Discovery 677 Senders: Initiator and Target 678 Scope: SW 680 iSCSIProtocolLevel= 682 Default is 1. 683 Result function is Minimum. 685 This key is used to negotiate the use of iSCSI features that 686 require different levels of protocol support (e.g., PDU formats, 687 end node semantics) for proper operation. 689 Negotiation of the iSCSIProtocolLevel key to a value 690 corresponding to an RFC indicates that both negotiating parties 691 are compliant to the RFC in question, and agree to support the 692 corresponding PDU formats and semantics on that iSCSI session. 693 An operational value of iSCSI ProtocolLevel = "x" on an iSCSI 694 session requires that the iSCSI protocol semantics on that iSCSI 695 session be a logical superset of the capabilities in all RFCs 696 that have claimed values of an iSCSIProtocolLevel less than "x". 698 An iSCSIProtocolLevel key negotiated to "0" indicates that the 699 implementation does not claim a specific iSCSI protocol level. 701 An iSCSIProtocolLevel key negotiated to "2" or higher is required 702 to enable use of features defined in this RFC. 704 If the negotiation answer is ignored by the acceptor, or the 705 answer from the remote iSCSI end point is key=NotUnderstood, then 706 the features defined in this RFC, and the features defined in any 707 RFC requiring a key value greater than "2" MUST NOT be used. 709 8. Security Considerations 711 At the time of writing this document does not introduce any new 712 security considerations other than those described in [RFC3720]. 713 Consequently, all the iSCSI-related security text in [RFC3723] is 714 also directly applicable to this document. 716 9. IANA Considerations 718 This document modifies or creates a number of iSCSI-related 719 registries. The following iSCSI-related registries are modified: 721 1. iSCSI Task Management Functions Codes 723 Name of the existing registry: "iSCSI TMF Codes" 724 Additional entries: 726 9, QUERY TASK, [RFCxxx] 728 10, QUERY TASK SET, [RFCxxx] 730 11, I_T NEXUS RESET, [RFCxxx] 732 12, QUERY ASYNCHRONOUS EVENT, [RFCxxx] 734 --------------------------------------------------------- 735 RFC EDITORS NOTE: The above reference to [RFCxxx] should 736 reference this RFC, and this note should be removed. 737 --------------------------------------------------------- 739 2. iSCSI Login/Text Keys 741 Name of the existing registry: "iSCSI Text Keys" 742 Fields to record in the registry: Assigned value and its 743 associated RFC reference: 745 iSCSIProtocolLevel, [RFCxxx] 747 --------------------------------------------------------- 748 RFC EDITORS NOTE: The above references to [RFCxxx] should 749 reference this RFC, and this note should be removed. 750 --------------------------------------------------------- 752 This document creates the following iSCSI-related registries for 753 IANA to manage. 755 3. iSCSI Protocol Level 757 Name of new registry: "iSCSI Protocol Level" 759 Namespace details: Numerical values from 0 to 31 761 Information that must be provided to assign a new value: An 762 IESG-approved standards track specification defining the 763 semantics and interoperability requirements of the proposed 764 new value and the fields to be recorded in the registry. 766 Assignment policy: 768 The assignments of these values must be coordinated with the 769 INCITS T10 committee; therefore review by an expert that 770 maintains an association with that committee is required prior 771 to IESG approval of the associated specification. After 772 creation of the registry, values are to be assigned 773 sequentially (for example, any value greater than 4 will not 774 be assigned until after the value 4 has been assigned). 776 1 and 3-31: range reserved by IANA for assignment in this 777 registry. 779 Fields to record in the registry: Assigned value, and its 780 associated RFC reference. 782 0, [RFCxxx] 784 2, [RFCxxx] 786 --------------------------------------------------------- 787 RFC EDITORS NOTE: The above references to [RFCxxx] should 788 reference this RFC, and this note should be removed. 789 --------------------------------------------------------- 791 Allocation Policy: 793 Expert review ([IANA]) and Standards Action ([IANA]) 795 4. iSCSI Task Management Response Codes 797 Name of new registry: "iSCSI TMF Response Codes" 798 Namespace details: Numerical values that can fit in 8 bits. 800 Information that must be provided to assign a new value: An 801 IESG-approved specification defining the semantics and 802 interoperability requirements of the proposed new value and 803 the fields to be recorded in the registry. 805 Assignment policy: 807 If the requested value is not already assigned, it may be 808 assigned to the requester. 810 8-254: Range reserved by iANA for assignment in this registry. 812 Fields to record in the registry: Assigned value, Operation 813 Name, and its associated RFC reference. 815 0x0, Function complete, [RFC3720] 817 0x1, Task does not exist, [RFC3720] 819 0x2, LUN does not exist, [RFC3720] 821 0x3, Task still allegiant, [RFC3720] 823 0x4, Task allegiance reassignment not supported, [RFC3720] 825 0x5, Task management function not supported, [RFC3720] 827 0x6, Function authorization failed, [RFC3720] 829 0x7, Function succeeded, [RFCxxx] 831 255, Function rejected, [RFC3720] 833 ------------------------------------------------------------ 834 RFC EDITORS NOTE: The above reference to [RFCxxx] should 835 reference this RFC, and this note should be removed. 836 ------------------------------------------------------------ 838 Allocation Policy: 840 Standards Action ([IANA]) 842 10. References 844 10.1 Normative References 846 [RFC2119] Bradner, S. "Key Words for use in RFCs to Indicate 847 Requirement Levels", BCP 14, RFC 2119, March 1997. 849 [RFC3720] Satran, J., Meth, K., Sapuntzakis, C., Chadalapaka, 850 M., and E. Zeidner, "Internet Small Computer Systems 851 Interface (iSCSI)", RFC 3720, April 2004. 853 [RFC3723] Aboba, B., Tseng, J., Walker, J., Rangan, V., and 854 Travostino, F., "Securing Block Storage Protocols 855 over IP", RFC 3723, April 2004. 857 [RFC5048] Chadalapaka, M., "Internet Small Computer System 858 Interface (iSCSI) Corrections and Clarifications", 859 RFC 5048, October 2007. 861 [draft-ietf-storm-iscsi-cons-xx] Chadalapaka, M., Satran, J., 862 Kalman, M., "iSCSI Protocol (consolidated)", RFC xxx, 863 Date 2011. 865 ------------------------------------------------------------ 866 RFC EDITORS NOTE: The above references to [draft-ietf-storm- 867 iscsi-cons-xx] and [RFCxxx] should reference the RFC number 868 assigned to that draft, and this note should be removed. 869 ------------------------------------------------------------ 871 [IANA] Narten, T. and H. Alvestrand, "Guidelines for Writing 872 an IANA Considerations Section in RFCs", BCP 26, RFC 873 5226, May 2008. 875 [SAM2] T10/1157D, SCSI Architecture Model - 2 (SAM-2). 877 [SAM4] ISO/IEC 14776-414, SCSI Architecture Model - 4 (SAM- 878 4). 880 [SAM5] T10/2104D rev r04, SCSI Architecture Model - 5 (SAM- 881 5), Committee Draft. 883 [SPC4] T10/1731D rev r23, SCSI Primary Commands - 4 (SPC-4), 884 Committee Draft. 886 10.2 Additional Reference Sources 888 For more information on the SCSI Architecture Model, contact the 889 INCITS T10 Technical Committee for SCSI Storage Interfaces at 890 http://www.t10.org. 892 11. Acknowledgements 894 The Storage Maintenance (STORM) Working Group in the Transport 895 Area of the IETF has been responsible for defining these 896 additions to the iSCSI protocol (apart from other relevant IP 897 Storage protocols). The editor acknowledges the contributions of 898 the entire working group. 899 The following individuals directly contributed to identifying 900 [RFCxxx] issues and/or suggesting resolutions to the issues 901 clarified in this document: David Black, Rob Elliott. This 902 document benefited from all of these contributions. 903 ------------------------------------------------------------ 904 RFC EDITORS NOTE: The above reference to [RFCxxx] should 905 reference this RFC, and this note should be removed. 906 ------------------------------------------------------------ 908 Author's Addresses 910 Frederick Knight 911 7301 Kit Creek Road 912 P.O. Box 13917 913 Research Triangle Park, NC 27709, USA 914 Phone: +1-919-476-5362 915 Email: knight@netapp.com 917 Mallikarjun Chadalapaka 918 Microsoft 919 One Microsoft Way 920 Redmond, WA 98052 USA 921 Email: cbm@chadalapaka.com