ANSI INCITS 309-1997 Information Technology - Serial Storage Architecture - SCSI-3 Protocol (SSA-S3P).pdf

1、ANSI INCITS 309-1997 (R2002)(formerly ANSI NCITS 309-1997)for Information Technology Serial Storage Architecture -SCSI-3 Protocol (SSA-S3P)American National Standardfor Information Technology Serial Storage Architecture SCSI-3 Protocol (SSA-S3P)ANSINCITS 309-1997SecretariatInformation Technology Ind

2、ustry CouncilApproved December 1, 1997American National Standards Institute, Inc.AbstractThis document describes the SCSI-3 mapping protocol (SSA-S3P) to be used on the Serial Storage Ar-chitecture - Transport Layer 2 (SSA-TL2).Approval of an American National Standard requires verification by ANSI

3、thatthe requirements for due process, consensus, and other criteria for approvalhave been met by the standards developer.Consensus is established when, in the judgement of the ANSI Board ofStandards Review, substantial agreement has been reached by directly andmaterially affected interests. Substant

4、ial agreement means much more thana simple majority, but not necessarily unanimity. Consensus requires that allviews and objections be considered, and that a concerted effort be madetowards their resolution.The use of American National Standards is completely voluntary; theirexistence does not in an

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6、tation on any American NationalStandard. Moreover, no person shall have the right or authority to issue aninterpretation of an American National Standard in the name of the AmericanNational Standards Institute. Requests for interpretations should beaddressed to the secretariat or sponsor whose name

7、appears on the titlepage of this standard.CAUTION NOTICE:This American National Standard may be revised orwithdrawn at any time. The procedures of the American National StandardsInstitute require that action be taken periodically to reaffirm, revise, orwithdraw this standard. Purchasers of American

8、National Standards mayreceive current information on all standards by calling or writing the AmericanNational Standards Institute.American National StandardPublished byAmerican National Standards Institute, Inc.11 West 42nd Street, New York, NY 10036Copyright 1998 by Information Technology Industry

9、CouncilAll rights reserved.No part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without prior written permission of the publisher.Printed in the United States of AmericaCAUTION:The developers of this standard have requested that holders of patents

10、that may berequired for the implementation of the standard disclose such patents to the publisher. However,neither the developers nor the publisher have undertaken a patent search in order to identifywhich, if any, patents may apply to this standard.As of the date of publication of this standard, fo

11、llowing calls for the identification of patents thatmay be required for the implementation of the standard, notice of one or more such claims hasbeen received.By publication of this standard, no position is taken with respect to the validity of this claim or ofany rights in connection therewith. The

12、 known patent holder(s) has (have), however, filed a state-ment of willingness to grant a license under these rights on reasonable and nondiscriminatoryterms and conditions to applicants desiring to obtain such a license. Details may be obtained fromthe publisher.No further patent search is conducte

13、d by the developer or publisher in respect to any standard itprocesses. No representation is made or implied that this is the only license that may be requiredto avoid infringement in the use of this standard.d. iContentsPageForeword.iiiIntroduction vii1Scope 11.1 SSA family of standards . 11.2 SCSI

14、-3 family of standards . 32References . 32.1 Normative references . 32.2 Informative references 43Definitions, symbols, abbreviations, and conventions 43.1 Definitions . 43.2 Symbols and abbreviations. 53.3 Conventions 54General . 64.1 Overview. 64.2 Model 75Frames 86SSA-S3P message structure 86.1 S

15、ummary of SSA-S3P SMSs 106.2 SMS validation 106.3 SMS Buffer Full condition . 116.4 Limitation on task management SMSs . 126.5TAGfield values. 126.6 SCSI COMMAND SMS. 126.7 SCSI STATUS SMS . 156.8 CONFIRM STATUS SMS . 166.9 ENABLE AER SMS 186.10 AER SMS 186.11 ABORT TASK SMS 196.12 ABORT TASK SET SM

16、S 206.13 CLEAR TASK SET SMS. 206.14 TARGET RESET SMS . 216.15 CLEAR ACA SMS. 226.16 LOGICAL UNIT RESET SMS . 236.17 SCSI RESPONSE SMS 247Transport related items. 257.1 Spindle synchronization 257.2 Unit attention flag in the Initiator Table . 257.3 Effects of reset conditions. 258SSA-S3P changes fro

17、m parallel SCSI-3. 268.1 Untagged queuing is emulated . 268.2 Contingent Allegiance vs. Auto Contingent Allegiance. 268.3 Confirmed status. 278.4 Concurrent data transfers from a single target . 28iiPage8.5 Multiple logical paths 288.6 Unit attention. 298.7 Third party command support. 298.8 Optiona

18、l SCSI-3 features not supported in SSA-S3P. 298.9 Mode Page 02h parameter differences 30Tables1Bit ordering in a byte. 62Generic SMS format for initiator-generated SSA-S3P SMSs . 93Generic SMS format for target-generated SSA-S3P SMSs 94Summary of SSA-S3P SMSs 105SCSI COMMAND SMS. 136QUEUE CNTL field

19、 values 147SCSI STATUS SMS . 158Meaning of FLAGand LINKbits 159RETURNCODEvalues for the SCSI STATUS SMS 1610SENSEDATAfield 1611CONFIRM STATUS SMS. 1712ENABLE AER SMS 1813AER SMS 1914ABORT TASK SMS 1915ABORT TASK SET SMS 2016CLEAR TASK SET SMS. 2117TARGET RESET SMS . 2218CLEAR ACA SMS. 2219LOGICAL UN

20、IT RESET SMS. 2420SCSI RESPONSE SMS 2421RETURNCODEvalues for the SCSI RESPONSE SMS. 2522Contingent Allegiance Table entry format. 27Figures1Relationship of the SSA standards. 22SCSI-3 family 3AnnexesAParallel SCSI-3 message to SSA-S3P SMS conversion 31BSome differences between SSA-S3P and parallel S

21、CSI-3. 34CProtocol services model 36DTransport Service handling. 49iiiForeword(This foreword is not part of American National Standard NCITS 309-1997.)This document describes the SCSI-3 protocol (SSA-S3P) to be used on the SerialStorage Architecture - Transport Layer 2 (SSA-TL2). SSA defines a seria

22、l interfacehierarchy to be used for purposes within its distance and performance characteris-tics, including but not limited to storage subsystems.The Serial Storage Architecture fills a need in the evolution from parallel to serial in-terfaces for storage devices. It meets the space constraints and

23、 cabling consider-ations for high-density storage arrays with a commensurate improvement in reliability(an architected error recovery, redundant paths to devices, a wrap mode for self-test,line fault detection and a balanced signaling scheme that achieves a low error rate)and configurability (the ab

24、ility to hot-plug devices, the self-configuration capability,the 20-meter length of cable segments).The physical layer allows for a CMOS implementation to achieve an economical andsmall package size, an efficient use of bandwidth, a small frame size to reduce bufferexpense and the capability for sel

25、f-configuration are also needed. The physical re-quirements include 20-meter distance per cable segment, a small number of signalsto limit connector and cable expense, and a low voltage implementation.This standard was developed by Task Group T10.1 of Accredited Standards Commit-tee NCITS during 199

26、6-97. The standards approval process started in 1997.This document includes four informative annexes, which are not part of the standard.Requests for interpretation, suggestions for improvement or addenda, or defect re-ports are welcome. They should be sent to National Committee for InformationTechn

27、ology Standards (NCITS), ITI, 1250 Eye Street, NW, Suite 200, Washington,DC 20005-3922.This standard was processed and approved for submittal to ANSI by NCITS. Com-mittee approval of the standard does not necessarily imply that all committee mem-bers voted for approval. At the time it approved this

28、standard, NCITS had thefollowing members:Karen Higginbottom, Chair (Acting)Karen Higginbottom, Vice-ChairMonica Vago, SecretaryOrganization Represented Name of RepresentativeAMP, Inc. .John HillCharles Brill (Alt.)Apple Computer, IncDavid MichaelJerry Kellenbenz (Alt.)ATb) define the data field form

29、at of the SSA-S3P SMSs;c) support for dual port and alternate pathing;d) provide support for auto-sense;e) provide support for third-party operations;f) other capabilities that fit within the scope of SSA-S3P that may be proposed during thedevelopment phase by the participants in the project.This do

30、cument defines the SCSI-3 protocol layer of the Serial Storage Architecture (SSA). SSA definesa serial interface hierarchy to be used for purposes within its distance and performance characteristics,including but not limited to storage subsystems. This standard is intended to be used with a transpor

31、tlayer protocol e.g., SSA Transport Layer 2 (SSA-TL2) and a physical layer e.g., SSA Physical Layer 2(SSA-PH2).1.1 SSA family of standardsThis document describes an upper-level protocol of Serial Storage Architecture. SSA-S3P is a mappingof the existing SCSI-2 protocol, ANSI X3.131-1994, with extens

32、ions to map SCSI-2 to the SSA seriallink.Figure 1 shows the relationships of the SSA standardsANSI NCITS 309-199721.1.1 SSA-S2PSerial Storage Architecture - SCSI-2 Protocol (SSA-S2P) (ANSI X3.294) defines the SCSI-2 Protocolused to run with the SSA transport layers 1 or 2. SSA-S2P is intended to ope

33、rate on the followingtransport and physical layers: SSA-TL1 with SSA-PH1, SSA-TL2 with SSA-PH1, and SSA-TL2 withSSA-PH2.1.1.2 SSA-TL1Serial Storage Architecture - (SSA-TL1) Transport Layer 1 (ANSI X3.295) defines the Transport layerthat supports SSA-S2P and requires SSA-PH1.1.1.3 SSA-PH1Serial Stora

34、ge Architecture - (SSA-PH1) Physical Layer 1 (ANSI X3.293) defines the Physical layer thatsupports SSA-TL1 and SSA-TL2, and consists of the electrical characteristics of the interface and theconnectors.1.1.4 SSA-S3PSerial Storage Architecture - (SSA-S3P) SCSI-3 Protocol (this standard) defines the S

35、CSI-3 Protocolused with the SSA transport layer 2. SSA-S3P is intended to operate on the following transport andphysical layers: SSA-TL2 with SSA-PH1, and SSA-TL2 with SSA-PH2.1.1.5 SSA-TL2Serial Storage Architecture - (SSA-TL2) Transport Layer 2 (ANSI NCITS 308) defines the Transportlayer that supp

36、orts SSA-S2P and SSA-S3P and requires SSA-PH1 or SSA-PH2.Figure 1 - Relationship of the SSA standardsANSI NCITS 309-199731.1.6 SSA-PH2Serial Storage Architecture - (SSA-PH2) Physical Layer 2 (ANSI NCITS 307) defines the Physical layerthat supports SSA-TL2, and consists of the electrical characterist

37、ics of the interface and the connectors.1.2 SCSI-3 family of standardsFigure 2 is intended to show the relationship of this document to other SCSI-3 standards. The figure isnot intended to imply a relationship such as hierarchy, protocol stack, or system architecture. Itindicates the applicability o

38、f a standard to the implementation of a given transport.2 ReferencesCopies of the following documents can be obtained from ANSI: Approved ANSI standards, approvedand draft international and regional standards (ISO, IEC, CEN/CENELEC), and approved foreignstandards (including BSI, JIS, and DIN). For f

39、urther information, contact ANSI Customer ServiceDepartment at 212-642-4900 (phone), 212-302-1286 (fax) or via the World Wide Web athttp:/www.ansi.org.2.1 Normative referencesThe following standards contain provisions which, through reference in SSA-S3P, constitute provisionsof this American Nationa

40、l Standard. At the time of publication, the editions indicated were valid. Allstandards are subject to revision, and parties to agreements based on this American National StandardSCSI-3 BlockCommandsSCSI-3StreamCommandsSCSI-3GraphicsCommandsSCSI-3MediumChangerCommandsSCSI-3Multi-MediaCommandsSCSI-3C

41、ontrollerCommandsSCSI-3 Primary CommandsSCSI-3 Architecture ModelSCSI-3 InterlockedProtocolSerialBusProtocolFibreChannelProtocolSSA-S3P(SCSI-3Protocol)SCSI-3 ParallelInterfaceIEEE1394FibreChannelSSA-TL2b) Command descriptor blocks;c) Status byte;d) Sense bytes.ANSI NCITS 309-19977Except where necess

42、ary for clarity the above functions are not described in this document (see ANSISCSI-3 standards for information). SSA-S3P concentrates on mapping the following aspects of parallelSCSI-3:a) Bus functions;b) Addressing;c) Messages.SSA-S3P supports Webs containing strings, loops, and switches. The con

43、cepts of initiator, target, andLogical Unit are retained although SSA-S3P supports larger configurations than parallel SCSI-3.Initiators and targets may be freely mixed throughout the Web. Each node may have from 1 to 126physical ports.SSA-S3P offers the following benefits compared to the parallel S

44、CSI bus:a) Open-ended Webs with alternative paths for availability and performance;b) Full-duplex communication with spatial reuse on strings and loops;c) Frame multiplexing;d) No overhead for arbitration, disconnection, or reselection;e) Integrated spindle synchronization for array applications;f)

45、Fewer initiator-target exchanges;g) Concurrent tasks on the same device or different devices;h) Out-of-order data transfers.Untagged queuing may be simply emulated with Tagged Queuing. In SSA, the target effectivelydisconnects after each frame because of frame multiplexing. Hence each command shall

46、have a tag foridentification. Untagged command queuing may be simply emulated by having the initiator have onlyone outstanding command, re-use the same tag, and use the simple queue type.4.2 Model4.2.1 SAM servicesThe SSA-S3P protocol layer maps the SAM Services model with some additional enhancemen

47、ts ontothe SSA-TL2 transport layer services.4.2.2 Logical pathsThe SSA-S3P protocol layer provides a logical path between the Application Client and the nodeidentified by a Unique ID. This outgoing logical path guarantees ordered delivery of tasks. A feature inaddition to the SAM Services is the abi

48、lity of the Application Client to request multiple logical paths andcontrol what tasks use which logical path. If the task uses the Confirmed Status feature, the SSA-S3Player will automatically redirect all outstanding tasks to use an alternate path (if any exist) in the event ofa path failure.4.2.2

49、.1 Use of multiple outgoing logical pathsIf an initiator uses multiple outgoing logical paths, then ordering across logical paths is not guaranteed(although ordering is guaranteed within a logical path).4.2.2.2 Use of multiple return logical pathsIf an initiator uses multiple return logical paths, then receipt of SCSI STATUS SMSs received may notindicate the order the commands were executed within the target (although ordering is guaranteedwithin a logical path).4.2.3 Path controlThe SSA-S3P protocol layer controls the use of paths to guarantee a logical path when needed.ANSI NCITS