ISO/IEC 14776-263:2018

Information technology - Small Computer System Interface (SCSI) - Part 263: SAS Protocol Layer - 3 (SPL-3)

ISO/IEC 14776-263:2018 The SCSI family of standards provides for many different transport protocols that define the rules for exchanging information between different SCSI devices. This document defines the rules for exchanging information between SCSI devices using a serial interconnect. Other SCSI transport protocol standards define the rules for exchanging information between SCSI devices using other interconnects.

General Information

• Status: Published
• Publication Date: 28-Oct-2018
• ICS: 35.200 - Interface and interconnection equipment
• Technical Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Current Stage: PPUB - Publication issued
• Start Date: 29-Oct-2018
• Completion Date: 05-Nov-2018

Overview

ISO/IEC 14776-263:2018 - Information technology - Small Computer System Interface (SCSI) - Part 263: SAS Protocol Layer - 3 (SPL-3) - defines the protocol rules for exchanging SCSI information over a Serial Attached SCSI (SAS) serial interconnect. As part of the SCSI standards family, SPL-3 specifies device and interconnect behavior for SAS-based systems (physical links, logical links, ports and expanders), enabling interoperable storage hardware and firmware across vendors.

Keywords: ISO/IEC 14776-263:2018, SAS Protocol Layer 3, SPL-3, SCSI, serial interconnect, SAS devices

Key topics and technical requirements

SPL-3 covers architecture and protocol-level requirements that implementers must follow. Major technical topics in the standard include:

• Architecture and link model
  • Physical links, phys and logical links
  • Narrow and wide ports; persistent connections and pathways
• Names, identifiers and addressing
  • SAS addresses, NAA formats, port names, phy identifiers and hashed SAS addresses
• State machines and event handling
  • Transmit/receive data paths, state machine conventions, reset sequences (hard reset, I_T nexus loss)
• Expander device model and routing
  • Expander ports, Expander Connection Manager (ECM), Expander Connection Router (ECR), Broadcast Propagation Processor (BPP)
  • Route tables, routing attributes, topology handling and routing restrictions
• Discovery and configuration
  • Discover process traversal, broadcast/change handling, configuration subprocess and topology optimization
• Operational behaviors
  • Broadcast handling, advancing credit, connection establishment, zoning considerations

The document includes normative references, terms and definitions, UML conventions, bit/byte ordering and procedural notations - all of which are normative for compliant implementations.

Practical applications and who uses this standard

SPL-3 is a foundational standard for vendors and engineers building interoperable SAS storage systems:

• Hardware vendors designing SAS controllers, expanders, HBAs, enclosures and disk drives
• Firmware and driver developers implementing SAS protocol stacks, state machines and discovery logic
• Storage system architects and integrators ensuring topology, routing and zoning compliance in data centers
• Interoperability labs and QA/test teams creating conformance test suites and verifying device behavior under reset, broadcast and routing scenarios
• Standards bodies and technical writers referencing protocol definitions and normative behaviors

Adoption ensures reliable SAS communication, predictable device discovery and consistent behavior across multi-vendor storage environments.

Related standards

• Part of the ISO/IEC 14776 SCSI family (other transport protocol parts address alternate interconnects)
• Complementary to SCSI command set standards and vendor-specific implementation guides

For implementers and procurement teams, ISO/IEC 14776-263:2018 (SPL-3) is the authoritative reference to design, test and validate SAS protocol layer behavior and interoperability.

Standards Content (Sample)

ISO/IEC 14776-263
Edition 1.0 2018-10
INTERNATIONAL
STANDARD
colour
inside
Information technology – Small Computer System Interface (SCSI) –
Part 263: SAS Protocol Layer – 3 (SPL-3)

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ISO/IEC 14776-263
Edition 1.0 2018-10
INTERNATIONAL
STANDARD
colour
inside
Information technology – Small Computer System Interface (SCSI) –

Part 263: SAS Protocol Layer – 3 (SPL-3)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 35.200 ISBN 978-2-8322-6190-3

ISO/IEC
14776-263:2018
Information technology -
Small Computer System Interface (SCSI) -
Part 263:SAS Protocol Layer - 3 (SPL-3)
Reference
ISO/IEC 14775-263
FOREWORD. 39
INTRODUCTION. 41
SCSI standards family. 42
1 Scope. 44
2 Normative references. 45
3 Terms, definitions, symbols, abbreviations, keywords, and conventions. 46
3.1 Terms and definitions . 46
3.2 Symbols and abbreviations . 75
3.2.1 Abbreviations . 75
3.2.2 Units. 77
3.2.3 Symbols . 77
3.2.4 Mathematical operators . 78
3.3 Keywords. 78
3.4 Editorial conventions . 79
3.5 Numeric and character conventions. 80
3.5.1 Numeric conventions . 80
3.5.2 Units of measure. 81
3.5.3 Byte encoded character strings conventions . 82
3.6 UML notation conventions. 82
3.6.1 Notation conventions overview . 82
3.6.2 Constraint and note conventions . 82
3.6.3 Class diagram conventions. 83
3.6.4 Object diagram conventions . 88
3.7 State machine conventions . 90
3.7.1 State machine conventions overview. 90
3.7.2 Transitions . 91
3.7.3 Messages, requests, indications, confirmations, responses, and event notifications. 91
3.7.4 State machine counters, timers, and variables. 91
3.7.5 State machine arguments. 92
3.8 Bit and byte ordering . 92
3.9 Notation for procedures and functions. 93
4 General . 94
4.1 Architecture . 94
4.1.1 Architecture overview. 94
4.1.2 Physical links and phys. 96
4.1.3 Logical links . 100
4.1.4 Narrow ports and wide ports. 100
4.1.5 Application clients and device servers. 104
4.1.6 SAS devices. 104
4.1.7 Expander devices . 105
4.1.8 Service delivery subsystem . 106
4.1.9 Domains. 107
4.1.10 Expander device topologies. 110
4.1.10.1 Expander device topology overview. 110
4.1.10.2 Expander device topologies . 111
4.1.11 Pathways . 113
4.1.12 Connections. 113
4.1.13 Persistent connections. 115
4.1.13.1 Persistent connection operation. 115
4.1.13.2 Persistent connection support. 116
4.1.14 Advancing credit . 116
4.1.15 Broadcasts. 116
4.2 Names and identifiers. 118

4.2.1 Names and identifiers overview. 118
4.2.2 NAA IEEE Registered format identifier . 120
4.2.3 NAA Locally Assigned format identifier. 121
4.2.4 SAS address. 121
4.2.5 Hashed SAS addresses. 121
4.2.6 Device names and expander device SAS addresses. 122
4.2.7 Device names for SATA devices with world wide names . 123
4.2.8 Port names. 123
4.2.9 Port identifiers and SAS port SAS addresses. 123
4.2.10 Phy identifiers . 124
4.3 State machines. 125
4.3.1 State machine overview. 125
4.3.2 Transmit data path. 126
4.3.3 Receive data path. 131
4.3.4 State machines and SAS Device, SAS Port, and SAS Phy classes. 135
4.4 Events. 137
4.4.1 Reset sequences . 137
4.4.2 Hard reset . 139
4.4.2.1 Hard reset overview . 139
4.4.2.2 Additional hard reset processing by SAS ports. 139
4.4.2.3 Additional hard reset processing by expander ports . 139
4.4.3 I_T nexus loss. 139
4.4.4 Power loss expected. 140
4.5 Expander device model. 141
4.5.1 Expander device model overview . 141
4.5.2 Expander ports. 142
4.5.3 Expander connection manager (ECM). 143
4.5.4 Expander connection router (ECR). 143
4.5.5 Broadcast propagation processor (BPP) . 144
4.5.6 Expander device interfaces. 144
4.5.6.1 Expander device interface overview. 144
4.5.6.2 Expander device interfaces detail . 146
4.5.6.3 ECM interface. 147
4.5.6.4 ECR interface. 149
4.5.6.5 BPP interface . 151
4.5.7 Expander device routing . 152
4.5.7.1 Routing attributes and routing methods . 152
4.5.7.2 Expander device topology routing attribute restrictions. 153
4.5.7.3 Connection request routing . 153
4.5.7.4 Expander route table. 153
4.5.7.4.1 Expander route table overview . 153
4.5.7.4.2 Phy-based expander route table. 154
4.5.7.4.3 Expander-based expander route table . 155
4.5.8 Expander device reduced functionality . 155
4.5.9 Broadcast (Expander) handling . 156
4.6 Discover process. 156
4.6.1 Discover process overview . 156
4.6.2 Starting the discover process (Broadcast (Change) handling) . 156
4.6.3 Discover process traversal. 157
4.6.4 Discover process in a self-configuring expander device. 159
4.6.5 Enabling multiplexing. 160
4.7 Configuration subprocess. 160
4.7.1 Configuration subprocess overview. 160
4.7.2 Allowed expander device topologies. 161
4.7.3 Externally configurable expander device route table optimization. 162
4.7.4 Externally configurable expander device expander route index order. 163
4.8 Zoning. 170

4.8.1 Zoning overview. 170
4.8.2 Zoning expander device requirements. 174
4.8.3 Zoning operation. 177
4.8.3.1 Zone phy information. 177
4.8.3.2 Zone groups . 179
4.8.3.3 Zone permission table. 180
4.8.3.4 Zoning expander route table . 182
4.8.3.5 Source zone group and destination zone group determination. 183
4.8.4 Zone phy information and link reset sequences . 184
4.8.5 Broadcast processing in a zoning expander device with zoning enabled. 187
4.8.6 Zone configuration . 188
4.8.6.1 Zone configuration overview . 188
4.8.6.2 Lock step. 188
4.8.6.3 Load step. 189
4.8.6.4 Activate step. 190
4.8.6.5 Unlock step. 190
4.8.6.6 Zone lock inactivity timer. 191
4.8.6.7 Enable a zoning expander device . 191
4.9 SAS device and expander device power conditions. 191
4.10 Phy power conditions . 192
4.10.1 Low phy power conditions. 192
4.10.1.1 Low phy power conditions overview. 192
4.10.1.2 Active phy power condition. 192
4.10.1.3 Partial phy power condition . 192
4.10.1.4 Slumber phy power condition. 192
4.10.1.5 End device low phy power conditions . 193
4.10.1.6 Expander device low phy power conditions . 193
4.10.2 SATA phy power conditions. 194
4.11 Phy test functions . 194
4.11.1 Phy test functions overview . 194
4.11.2 Transmit pattern phy test function. 195
4.12 Phy events. 195
4.13 Using POWER DISABLE signal to create a power on event. 200
4.13.1 Using POWER DISABLE signal to create a power on event overview. 200
4.13.2 Discovering POWER DISABLE signal support. 200
4.13.3 Using a management device server to control the POWER DISABLE signal . 201
5 Phy layer . 202
5.1 Phy layer overview . 202
5.2 8b10b coding. 202
5.2.1 8b10b coding overview . 202
5.2.2 8b10b coding notation conventions . 202
5.3 Character encoding and decoding. 203
5.3.1 Character encoding and decoding overview. 203
5.3.2 Bit transmission order . 203
5.3.3 Character transmission order. 203
5.3.4 Frame transmission order. 204
5.3.5 Running disparity (RD). 204
5.3.6 Data characters. 204
5.3.7 Control characters. 210
5.3.8 Encoding characters in the transmitter . 211
5.3.9 Decoding characters in the receiver . 211
5.4 Dwords, primitives, data dwords, and invalid dwords. 212
5.5 Bit order. 212
5.6 Out of band (OOB) signals . 214
5.6.1 OOB signals overview. 214
5.6.2 Transmission of OOB signals . 215

5.6.3 Receiver detection of OOB signals. 216
5.6.4 SATA port selection signal. 218
5.6.5 Phy power conditions. 218
5.7 Phy capabilities bits. 218
5.8 BMC coding. 222
5.8.1 BMC coding overview . 222
5.8.2 TTIU bit cell encoding in the transmitter . 223
5.8.3 TTIU bit transmission order. 224
5.8.4 TTIU bit cell decoding in the receiver. 224
5.9 Train_Tx-SNW TTIUs. 225
5.9.1 Train_Tx-SNW TTIU format. 225
5.9.2 Control/Status TTIU . 226
5.9.3 Error Response TTIU. 230
5.10 Phy reset sequences. 233
5.10.1 Phy reset sequences overview . 233
5.10.2 SATA phy reset sequence . 234
5.10.2.1 SATA OOB sequence . 234
5.10.2.2 SATA speed negotiation sequence. 234
5.10.3 SAS to SATA phy reset sequence. 235
5.10.4 SAS to SAS phy reset sequence . 236
5.10.4.1 SAS OOB sequence. 236
5.10.4.2 SAS speed negotiation sequence . 239
5.10.4.2.1 SAS speed negotiation sequence overview . 239
5.10.4.2.2 SAS speed negotiation sequence timing specifications . 240
5.10.4.2.3 Speed negotiation window (SNW) definitions. 241
5.10.4.2.3.1 SNW definitions overview . 241
5.10.4.2.3.2 SNW-1, SNW-2, and Final-SNW. 242
5.10.4.2.3.3 SNW-3. 243
5.10.4.2.3.4 Train_Tx-SNW . 245
5.10.4.2.3.4.1 Phy’s transmitter initial condition . 245
5.10.4.2.3.4.2 Transmitter training. 245
5.10.4.2.3.4.3 Pattern marker. 246
5.10.4.2.3.5 Train_Rx-SNW. 248
5.10.4.2.4 SAS speed negotiation sequence.251
5.10.4.2.5 SAS speed negotiation sequence examples . 252
5.10.4.2.6 Train_Tx pattern sequence. 260
5.10.4.2.6.1 Train_Tx pattern sequence overview. 260
5.10.4.2.6.2 Train_Tx pattern initial sequence. 261
5.10.4.2.6.3 Train_Tx pattern handshake sequence. 264
5.10.4.2.6.3.1 Train_Tx pattern handshake sequence overview. 264
5.10.4.2.6.3.2 Attached phy’s receiver increment or decrement request . 264
5.10.4.2.6.3.3 Attached phy’s receiver reference_1, reference_2, or no_equalization request . 267
5.10.4.2.6.4 Train_Tx pattern completion sequence. 269
5.10.4.2.6.5 Invalid TTIU sequence . 272
5.10.4.3 Multiplexing sequence. 273
5.10.5 Phy reset sequence after devices are attached. 274
5.11 Phy power condition sequences. 275
5.11.1 Transitioning from the active phy power condition to a low phy power condition . 275
5.11.2 Transitioning from a low phy power condition to the active phy power condition . 276
5.11.3 Events during low phy power condition. 276
5.12 SP (phy layer) state machine . 278
5.12.1 SP state machine overview. 278
5.12.2 SP transmitter and SP receiver. 280
5.12.3 OOB sequence states. 283
5.12.3.1 OOB sequence states overview. 283
5.12.3.2 SP0:OOB_COMINIT state. 284
5.12.3.2.1 State description. 284

5.12.3.2.2 Transition SP0:OOB_COMINIT to SP1:OOB_AwaitCOMX. 285
5.12.3.2.3 Transition SP0:OOB_COMINIT to SP3:OOB_AwaitCOMINIT_Sent. 285
5.12.3.2.4 Transition SP0:OOB_COMINIT to SP4:OOB_COMSAS. 285
5.12.3.3 SP1:OOB_AwaitCOMX state . 285
5.12.3.3.1 State description. 285
5.12.3.3.2 Transition SP1:OOB_AwaitCOMX to SP0:OOB_COMINIT. 285
5.12.3.3.3 Transition SP1:OOB_AwaitCOMX to SP4:OOB_COMSAS . 285
5.12.3.4 SP2:OOB_NoCOMSASTimeout state. 286
5.12.3.4.1 State description. 286
5.12.3.4.2 Transition SP2:OOB_NoCOMSASTimeout to SP0:OOB_COMINIT . 286
5.12.3.4.3 Transition SP2:OOB_NoCOMSASTimeout to SP4:OOB_COMSAS. 286
5.12.3.5 SP3:OOB_AwaitCOMINIT_Sent state . 286
5.12.3.5.1 State description. 286
5.12.3.5.2 Transition SP3:OOB_AwaitCOMINIT_Sent to SP4:OOB_COMSAS . 286
5.12.3.6 SP4:OOB_COMSAS state . 286
5.12.3.6.1 State description. 286
5.12.3.6.2 Transition SP4:OOB_COMSAS to SP5:OOB_AwaitCOMSAS_Sent. 287
5.12.3.6.3 Transition SP4:OOB_COMSAS to SP6:OOB_AwaitNoCOMSAS. 287
5.12.3.6.4 Transition SP4:OOB_COMSAS to SP7:OOB_AwaitCOMSAS . 287
5.12.3.7 SP5:OOB_AwaitCOMSAS_Sent state. 287
5.12.3.7.1 State description. 287
5.12.3.7.2 Transition SP5:OOB_AwaitCOMSAS_Sent to SP6:OOB_AwaitNoCOMSAS. 287
5.12.3.8 SP6:OOB_AwaitNoCOMSAS state. 287
5.12.3.8.1 State description. 287
5.12.3.8.2 Transition SP6:OOB_AwaitNoCOMSAS to SP0:OOB_COMINIT . 287
5.12.3.8.3 Transition SP6:OOB_AwaitNoCOMSAS to SP8:SAS_Start. 288
5.12.3.9 SP7:OOB_AwaitCOMSAS state .288
5.12.3.9.1 State description. 288
5.12.3.9.2 Transition SP7:OOB_AwaitCOMSAS to SP2:OOB_NoCOMSASTimeout. 288
5.12.3.9.3 Transition SP7:OOB_AwaitCOMSAS to SP6:OOB_AwaitNoCOMSAS. 288
5.12.3.9.4 Transition SP7:OOB_AwaitCOMSAS to SP16:SATA_COMWAKE. 288
5.12.3.9.5 Transition SP7:OOB_AwaitCOMSAS to SP26:SATA _SpinupHold. 288
5.12.4 SAS speed negotiation states. 289
5.12.4.1 SAS speed negotiation states overview. 289
5.12.4.2 Negotiation idle. 289
5.12.4.3 SP8:SAS_Start state. 292
5.12.4.3.1 State description. 292
5.12.4.3.2 Transition SP8:SAS_Start to SP0:OOB_COMINIT . 292
5.12.4.3.3 Transition SP8:SAS_Start to SP1:OOB_AwaitCOMX. 293
5.12.4.3.4 Transition SP8:SAS_Start to SP9:SAS_WindowNotSupported . 293
5.12.4.3.5 Transition SP8:SAS_Start to SP10:SAS_AwaitALIGN. 293
5.12.4.3.6 Transition SP8:SAS_Start to SP27:SAS_Settings . 293
5.12.4.4 SP9:SAS_WindowNotSupported state. 293
5.12.4.4.1 State description. 293
5.12.4.4.2 Transition SP9:SAS_WindowNotSupported to SP0:OOB_COMINIT. 293
5.12.4.4.3 Transition SP9:SAS_WindowNotSupported to SP14:SAS_Fail . 293
5.12.4.5 SP10:SAS_AwaitALIGN state. 293
5.12.4.5.1 State description. 293
5.12.4.5.2 Transition SP10:SAS_AwaitALIGN to SP0:OOB_COMINIT . 294
5.12.4.5.3 Transition SP10:SAS_AwaitALIGN to SP11:SAS_AwaitALIGN1. 294
5.12.4.5.4 Transition SP10:SAS_AwaitALIGN to SP12:SAS_AwaitSNW . 294
5.12.4.5.5 Transition SP10:SAS_AwaitALIGN to SP14:SAS_Fail. 294
5.12.4.6 SP11:SAS_AwaitALIGN1 state. 294
5.12.4.6.1 State description. 294
5.12.4.6.2 Transition SP11:SAS_AwaitALIGN1 to SP0:OOB_COMINIT . 294
5.12.4.6.3 Transition SP11:SAS_AwaitALIGN1 to SP12:SAS_AwaitSNW . 294
5.12.4.6.4 Transition SP11:SAS_AwaitALIGN1 to SP14:SAS_Fail. 294

5.12.4.7 SP12:SAS_AwaitSNW state . 295
5.12.4.7.1 State description. 295
5.12.4.7.2 Transition SP12:SAS_AwaitSNW to SP0:OOB_COMINIT. 295
5.12.4.7.3 Transition SP12:SAS_AwaitSNW to SP13:SAS_Pass. 295
5.12.4.8 SP13:SAS_Pass state. 295
5.12.4.8.1 State description. 295
5.12.4.8.2 Transition SP13:SAS_Pass to SP0:OOB_COMINIT. 295
5.12.4.8.3 Transition SP13:SAS_Pass to SP8:SAS_Start . 295
5.12.4.8.4 Transition SP13:SAS_Pass to SP15:SAS_PHY_Ready . 296
5.12.4.9 SP14:SAS_Fail state. 296
5.12.4.9.1 State description. 296
5.12.4.9.2 Transition SP14:SAS_Fail to SP1:OOB_AwaitCOMX. 296
5.12.4.9.3 Transition SP14:SAS_Fail to SP8:SAS_Start. 296
5.12.4.10 SP15:SAS_PHY_Ready state.
...