ISO/IEC 14776-150:2004

Information technology — Small Computer System Interface (SCSI) — Part 150: Serial Attached SCSI (SAS)

The SCSI protocol is designed to provide an efficient peer-to-peer I/O bus with the maximum number of hosts and peripherals determined by the bus width (8 or 16). Data may be transferred asynchronously or synchronously at rates that depend primarily on device implementation and cable length. SCSI is an I/O interface that may be operated over a wide range of media and transfer rates. This international standard specifies the functional requirements for the Serial Attached SCSI (SAS) physical interconnect, which is compatible with the Serial ATA physical interconnect. It also specifies three transport protocols, one to transport SCSI commands, another to transport Serial ATA commands to multiple SATA devices, and a third to support interface management. This standard is intended to be used in conjunctionwith SCSI and ATA command set standards.

Technologies de l'information — Interface de petit système d'ordinateur (SCSI) — Partie 150: SCSI attachée en série (SAS)

General Information

• Status: Published
• Publication Date: 30-Nov-2004
• ICS: 35.200 - Interface and interconnection equipment
• Technical Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Drafting Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Current Stage: 9093 - International Standard confirmed
• Start Date: 13-Jul-2018
• Completion Date: 12-Feb-2026

Overview

ISO/IEC 14776-150:2004 - Information technology - Small Computer System Interface (SCSI) - Part 150: Serial Attached SCSI (SAS) specifies the functional requirements for the Serial Attached SCSI (SAS) physical interconnect and associated transport protocols. The standard defines a SAS interface that is compatible with the Serial ATA (SATA) physical interconnect, and describes three transport protocols: one for transporting SCSI commands, one for transporting SATA commands to multiple SATA devices, and one for interface management. It is intended to be used together with SCSI and ATA command set standards.

Key topics and technical requirements

The standard covers detailed technical areas essential for interoperable SAS implementations:

• Architecture & topology: ports, phys, devices, domains, expanders, pathways and connections.
• Physical layer: cables, connectors (internal/external/backplane), backplanes and passive interconnect requirements.
• Electrical characteristics: transmitter/receiver specs, impedance, eye masks, jitter and compliance points.
• Phy layer: 8b10b encoding, character encoding/decoding, bit ordering, out‑of‑band (OOB) signals and phy reset/negotiation sequences.
• Transport protocols: SCSI-over-SAS transport, transport of SATA commands to multiple devices, and management/maintenance protocol.
• Device management and discovery: SAS addressing, device/port identifiers, hashed addresses and expander routing/discovery.
• State machines & reset behavior: transmit/receive state machines, hard reset sequences, and I_T nexus loss handling.
• Expanders & routing: expander device models, connection managers/routers, broadcast primitive processing and route table methods.
• Ancillary items such as READY LED electrical characteristics, spread spectrum clocking and test patterns.

Applications and who uses it

ISO/IEC 14776-150:2004 is essential for:

• Storage hardware designers implementing SAS controllers, host bus adapters (HBAs), backplanes, cables and connectors.
• Firmware and driver engineers implementing SAS/SATA transport, phy management, and reset/state machine logic.
• System architects and integrators building enterprise storage arrays, servers and SAN/NAS solutions that require SATA compatibility via SAS.
• Compliance and test labs validating electrical, timing and protocol compliance (eye masks, jitter, OOB, 8b10b encoding).
• Component manufacturers (expanders, connectors, cable assemblies) ensuring interoperability across SAS ecosystems.

Related standards

• SCSI command set standards (used in conjunction with SAS transport)
• ATA / Serial ATA (SATA) physical and command set standards (compatibility and transport)
• Other parts of the ISO/IEC 14776 series covering SCSI interfaces and transports

Keywords: ISO/IEC 14776-150:2004, Serial Attached SCSI, SAS, SCSI, SATA compatibility, SCSI-over-SAS, physical interconnect, 8b10b encoding, expanders, connectors, storage interface standards.

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 14776-150
First edition
2004-11
Information technology –
Small computer system interface (SCSI) –
Part 150:
Serial Attached SCSI (SAS)
Reference number
INTERNATIONAL ISO/IEC
STANDARD 14776-150
First edition
2004-11
Information technology –
Small computer system interface (SCSI) –
Part 150:
Serial Attached SCSI (SAS)
© ISO/IEC 2004
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any
means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
ISO/IEC Copyright Office Case postale 56 CH-1211 Genève 20 Switzerland
• • •
PRICE CODE
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For price, see current catalogue

14776-150 © ISO/IEC:2004(E) 3
CONTENTS
Foreword . 25
Introduction . 26
1 Scope. 29
2 References. 29
2.1 Normative references . 29
2.2 References under development . 29
2.3 Bibliography. 29
3 Definitions, symbols, abbreviations, keywords, and conventions .30
3.1 Definitions. 30
3.2 Symbols and abbreviations . 39
3.3 Keywords. 41
3.4 Editorial conventions . 42
3.5 Object and class diagram conventions. 43
3.6 State machine conventions . 46
3.6.1 State machine conventions overview. 46
3.6.2 Transitions . 46
3.6.3 Messages, requests, indications, confirmations, responses, and event notifications. 47
3.7 Bit and byte ordering . 47
3.8 Notation for procedures and functions. 48
4 General . 49
4.1 Architecture . 49
4.1.1 Architecture overview. 49
4.1.2 Physical links and phys. 50
4.1.3 Ports (narrow ports and wide ports). 52
4.1.4 SAS devices. 54
4.1.5 Expander devices (edge expander devices and fanout expander devices). 55
4.1.6 Service delivery subsystem . 57
4.1.7 Domains. 57
4.1.8 Expander device topologies. 59
4.1.8.1 Expander device topology overview. 59
4.1.8.2 Edge expander device set. 59
4.1.8.3 Expander device topologies . 60
4.1.9 Pathways . 63
4.1.10 Connections. 64
4.2 Names and identifiers. 66
4.2.1 Names and identifiers overview. 66
4.2.2 SAS addresses . 67
4.2.3 Hashed SAS address. 68
4.2.4 Device names . 68
4.2.5 Port names. 68
4.2.6 Port identifiers. 68
4.2.7 Phy identifiers . 69
4.3 State machines. 69
4.3.1 State machine overview. 69
4.3.2 Transmit data path. 71
4.3.3 State machines and SAS device, SAS port, and SAS phy objects. 76
4.4 Resets . 77
4.4.1 Reset overview . 77
4.4.2 Hard reset . 79
4.5 I_T nexus loss . 79
4.6 Expander device model. 79
4.6.1 Expander device model overview . 79
4.6.2 Expander ports. 80

4 14776-150 © ISO/IEC:2004(E)
4.6.3 Expander connection manager (ECM). 81
4.6.4 Expander connection router (ECR). 81
4.6.5 Broadcast primitive processor (BPP). 81
4.6.6 Expander device interfaces. 81
4.6.6.1 Expander device interface overview. 81
4.6.6.2 Expander device interfaces detail . 83
4.6.6.3 ECM interface. 83
4.6.6.4 ECR interface. 85
4.6.6.5 BPP interface . 86
4.6.7 Expander device routing . 86
4.6.7.1 Routing attributes and routing methods . 86
4.6.7.2 Connection request routing . 87
4.6.7.3 Expander route table. 87
4.6.7.4 Discover process. 88
4.6.7.5 Expander route index order. 90
5 Physical layer. 97
5.1 Physical layer overview . 97
5.2 Passive interconnect . 97
5.2.1 SATA cables and connectors. 97
5.2.2 SAS cables and connectors. 97
5.2.3 Connectors. 100
5.2.3.1 Connectors overview. 100
5.2.3.2 SAS plug connector. 100
5.2.3.3 SAS internal cable receptacle connector . 100
5.2.3.4 SAS backplane receptacle connector . 101
5.2.3.5 SAS internal connector pin assignments. 102
5.2.3.6 SAS external cable plug connector . 103
5.2.3.7 SAS external receptacle connector. 103
5.2.3.8 SAS external connector pin assignments.104
5.2.4 Cables. 104
5.2.4.1 SAS internal cables. 104
5.2.4.2 SAS external cables. 107
5.2.5 Backplanes . 107
5.3 Transmitter and receiver electrical characteristics . 107
5.3.1 Compliance points . 107
5.3.2 General interface specification. 107
5.3.3 Eye masks . 109
5.3.3.1 Eye masks overview. 109
5.3.3.2 Receive eye mask at IR, CR, and XR . 110
5.3.3.3 Jitter tolerance masks . 110
5.3.4 Signal characteristics at IT, CT, and XT . 111
5.3.5 Signal characteristics at IR, CR, and XR . 113
5.3.6 Jitter . 115
5.3.7 Receiver jitter tolerance . 116
5.3.8 Compliant jitter test pattern (CJTPAT). 116
5.3.9 Impedance specifications. 116
5.3.10 Electrical TxRx connections. 117
5.3.11 Transmitter characteristics. 118
5.3.12 Receiver characteristics. 120
5.3.13 Spread spectrum clocking. 121
5.3.14 Non-tracking clock architecture. 121
5.4 READY LED signal electrical characteristics. 121
6 Phy layer . 122
6.1 Phy layer overview . 122
6.2 Encoding (8b10b) . 122
6.2.1 Encoding overview. 122

14776-150 © ISO/IEC:2004(E) 5
6.2.2 8b10b coding introduction. 122
6.2.3 8b10b coding notation conventions . 122
6.3 Character encoding and decoding. 123
6.3.1 Introduction . 123
6.3.2 Transmission order . 124
6.3.3 Valid and invalid transmission characters. 124
6.3.3.1 Definitions. 124
6.3.3.2 Generating transmission characters. 128
6.3.3.3 Validity of received transmission characters . 128
6.4 Bit order. 128
6.5 Out of band (OOB) signals . 130
6.6 Phy reset sequences. 134
6.6.1 Phy reset sequences overview . 134
6.6.2 SATA phy reset sequence . 135
6.6.2.1 SATA OOB sequence . 135
6.6.2.2 SATA speed negotiation sequence. 136
6.6.3 SAS to SATA phy reset sequence. 136
6.6.4 SAS to SAS phy reset sequence . 137
6.6.4.1 SAS OOB sequence. 137
6.6.4.2 SAS speed negotiation sequence . 139
6.6.5 Phy reset sequence after devices are attached. 141
6.7 SP (phy layer) state machine . 142
6.7.1 SP state machine overview. 142
6.7.2 SP transmitter and receiver . 143
6.7.3 OOB sequence states. 145
6.7.3.1 OOB sequence states overview. 145
6.7.3.2 SP0:OOB_COMINIT state. 146
6.7.3.2.1 State description. 146
6.7.3.2.2 Transition SP0:OOB_COMINIT to SP1:OOB_AwaitCOMX. 146
6.7.3.2.3 Transition SP0:OOB_COMINIT to SP3:OOB_AwaitCOMINIT_Sent. 146
6.7.3.2.4 Transition SP0:OOB_COMINIT to SP4:OOB_COMSAS. 146
6.7.3.3 SP1:OOB_AwaitCOMX state . 146
6.7.3.3.1 State description. 146
6.7.3.3.2 Transition SP1:OOB_AwaitCOMX to SP0:OOB_COMINIT. 146
6.7.3.3.3 Transition SP1:OOB_AwaitCOMX to SP4:OOB_COMSAS . 146
6.7.3.4 SP2:OOB_NoCOMSASTimeout state. 146
6.7.3.4.1 State description. 146
6.7.3.4.2 Transition SP2:OOB_NoCOMSASTimeout to SP0:OOB_COMINIT. 146
6.7.3.4.3 Transition SP2:OOB_NoCOMSASTimeout to SP4:OOB_COMSAS. 146
6.7.3.5 SP3:OOB_AwaitCOMINIT_Sent state . 147
6.7.3.5.1 State description. 147
6.7.3.5.2 Transition SP3:OOB_AwaitCOMINIT_Sent to SP4:OOB_COMSAS . 147
6.7.3.6 SP4:OOB_COMSAS state . 147
6.7.3.6.1 State description. 147
6.7.3.6.2 Transition SP4:OOB_COMSAS to SP5:OOB_AwaitCOMSAS_Sent. 147
6.7.3.6.3 Transition SP4:OOB_COMSAS to SP6:OOB_AwaitNoCOMSAS. 147
6.7.3.6.4 Transition SP4:OOB_COMSAS to SP7:OOB_AwaitCOMSAS . 147
6.7.3.7 SP5:OOB_AwaitCOMSAS_Sent state. 147
6.7.3.7.1 State description. 147
6.7.3.7.2 Transition SP5:OOB_AwaitCOMSAS_Sent to SP6:OOB_AwaitNoCOMSAS. 147
6.7.3.8 SP6:OOB_AwaitNoCOMSAS state. 147
6.7.3.8.1 State description. 147
6.7.3.8.2 Transition SP6:OOB_AwaitNoCOMSAS to SP8:SAS_Start. 147
6.7.3.9 SP7:OOB_AwaitCOMSAS state .147
6.7.3.9.1 State description. 147
6.7.3.9.2 Transition SP7:OOB_AwaitCOMSAS to SP0:OOB_COMINIT. 148
6.7.3.9.3 Transition SP7:OOB_AwaitCOMSAS to SP6:OOB_AwaitNoCOMSAS. 148
6.7.3.9.4 Transition SP7:OOB_AwaitCOMSAS to SP16:SATA_COMWAKE. 148

6 14776-150 © ISO/IEC:2004(E)
6.7.3.9.5 Transition SP7:OOB_AwaitCOMSAS to SP2:OOB_NoCOMSASTimeout. 148
6.7.4 SAS speed negotiation states. 148
6.7.4.1 SAS speed negotiation states overview. 148
6.7.4.2 SP8:SAS_Start state. 150
6.7.4.2.1 State description. 150
6.7.4.2.2 Transition SP8:SAS_Start to SP10:SAS_AwaitALIGN. 150
6.7.4.2.3 Transition SP8:SAS_Start to SP9:SAS_RateNotSupported. 150
6.7.4.3 SP9:SAS_RateNotSupported state. 150
6.7.4.3.1 State description. 150
6.7.4.3.2 Transition SP9:SAS_RateNotSupported to SP14:SAS_Fail . 150
6.7.4.4 SP10:SAS_AwaitALIGN state. 150
6.7.4.4.1 State description. 150
6.7.4.4.2 Transition SP10:SAS_AwaitALIGN to SP0:OOB_COMINIT . 150
6.7.4.4.3 Transition SP10:SAS_AwaitALIGN to SP11:SAS_AwaitALIGN1. 150
6.7.4.4.4 Transition SP10:SAS_AwaitALIGN to SP12:SAS_AwaitSNW . 151
6.7.4.4.5 Transition SP10:SAS_AwaitALIGN to SP14:SAS_Fail. 151
6.7.4.5 SP11:SAS_AwaitALIGN1 state. 151
6.7.4.5.1 State description. 151
6.7.4.5.2 Transition SP11:SAS_AwaitALIGN1 to SP0:OOB_COMINIT . 151
6.7.4.5.3 Transition SP11:SAS_AwaitALIGN1 to SP14:SAS_Fail. 151
6.7.4.5.4 Transition SP11:SAS_AwaitALIGN1 to SP12:SAS_AwaitSNW . 151
6.7.4.6 SP12:SAS_AwaitSNW state . 151
6.7.4.6.1 State description. 151
6.7.4.6.2 Transition SP12:SAS_AwaitSNW to SP0:OOB_COMINIT. 151
6.7.4.6.3 Transition SP12:SAS_AwaitSNW to SP13:SAS_Pass. 151
6.7.4.7 SP13:SAS_Pass state. 151
6.7.4.7.1 State description. 151
6.7.4.7.2 Transition SP13:SAS_Pass to SP0:OOB_COMINIT. 152
6.7.4.7.3 Transition SP13:SAS_Pass to SP8:SAS_Start . 152
6.7.4.7.4 Transition SP13:SAS_Pass to SP15:SAS_PHY_Ready . 152
6.7.4.8 SP14:SAS_Fail state. 152
6.7.4.8.1 State description. 152
6.7.4.8.2 Transition SP14:SAS_Fail to SP1:OOB_AwaitCOMX. 152
6.7.4.8.3 Transition SP14:SAS_Fail to SP8:SAS_Start. 152
6.7.4.9 SP15:SAS_PHY_Ready state. 153
6.7.4.9.1 State description. 153
6.7.4.9.2 Transition SP15:SAS_PHY_Ready to SP0:OOB_COMINIT . 153
6.7.5 SATA host emulation states. 153
6.7.5.1 SATA host emulation states overview. 153
6.7.5.2 SP16:SATA_COMWAKE state .154
6.7.5.2.1 State description. 154
6.7.5.2.2 Transition SP16:SATA_COMWAKE to SP17:SATA_AwaitCOMWAKE. 155
6.7.5.3 SP17:SATA_AwaitCOMWAKE state. 155
6.7.5.3.1 State description. 155
6.7.5.3.2 Transition SP17:SATA_AwaitCOMWAKE to SP18:SATA_AwaitNoCOMWAKE . 155
6.7.5.4 SP18:SATA_AwaitNoCOMWAKE state. 155
6.7.5.4.1 State description. 155
6.7.5.4.2 Transition SP18:SATA_AwaitNoCOMWAKE to SP19:SATA_AwaitALIGN. 155
6.7.5.5 SP19:SATA_AwaitALIGN state. 155
6.7.5.5.1 State description. 155
6.7.5.5.2 Transition SP19:SATA_AwaitALIGN to SP20:SATA_AdjustSpeed. 155
6.7.5.5.3 Transition SP19:SATA_AwaitALIGN to SP0:OOB_COMINIT . 155
6.7.5.6 SP20:SATA_AdjustSpeed state. 155
6.7.5.6.1 State description. 155
6.7.5.6.2 Transition SP20:SATA_AdjustSpeed to SP0:OOB_COMINIT . 155
6.7.5.6.3 Transition SP20:SATA_AdjustSpeed to SP21:SATA_TransmitALIGN . 156
6.7.5.7 SP21:SATA_TransmitALIGN state. 156
6.7.5.7.1 State description. 156

14776-150 © ISO/IEC:2004(E) 7
6.7.5.7.2 Transition SP21:SATA_TransmitALIGN to SP0:OOB_COMINIT. 156
6.7.5.7.3 Transition SP21:SATA_TransmitALIGN to SP22:SATA_PHY_Ready. 156
6.7.5.8 SP22:SATA_PHY_Ready state. 156
6.7.5.8.1 State description. 156
6.7.5.8.2 Transition SP22:SATA_PHY_Ready to SP1:OOB_COMINIT. 156
6.7.5.8.3 Transition SP22:SATA_PHY_Ready to SP23:SATA_PM_Partial . 156
6.7.5.8.4 Transition SP22:SATA_PHY_Ready to SP24:SATA_PM_Slumber. 156
6.7.5.9 SP23:SATA_PM_Partial state. 156
6.7.5.9.1 State description. 156
6.7.5.9.2 Transition SP23:SATA_PM_Partial to SP16:SATA_COMWAKE. 156
6.7.5.9.3 Transition SP23:SATA_PM_Partial to SP18:SATA_AwaitNoCOMWAKE. 156
6.7.5.10 SP24:SATA_PM_Slumber state. 157
6.7.5.10.1 State description. 157
6.7.5.10.2 Transition SP24:SATA_PM_Slumber to SP16:SATA_COMWAKE. 157
6.7.5.10.3 Transition SP24:SATA_PM_Slumber to SP18:SATA_AwaitNoCOMWAKE . 157
6.8 SP_DWS (phy layer dword synchronization) state machine . 157
6.8.1 SP_DWS state machine overview . 157
6.8.2 SP_DWS receiver. 159
6.8.3 SP_DWS0:AcquireSync state. 159
6.8.3.1 State description. 159
6.8.3.2 Transition SP_DWS0:AcquireSync to SP_DWS1:Valid1. 159
6.8.4 SP_DWS1:Valid1 state. 159
6.8.4.1 State description. 159
6.8.4.2 Transition SP_DWS1:Valid1 to SP_DWS0:AcquireSync. 159
6.8.4.3 Transition SP_DWS1:Valid1 to SP_DWS2:Valid2 . 160
6.8.5 SP_DWS2:Valid2 state. 160
6.8.5.1 State description. 160
6.8.5.2 Transition SP_DWS2:Valid2 to SP_DWS0:AcquireSync. 160
6.8.5.3 Transition SP_DWS2:Valid2 to SP_DWS3:SyncAcquired. 160
6.8.6 SP_DWS3:SyncAcquired state. 160
6.8.6.1 State description. 160
6.8.6.2 Transition SP_DWS3:SyncAcquired to SP_DWS4:Lost1 . 160
6.8.7 SP_DWS4:Lost1 state . 160
6.8.7.1 State description. 160
6.8.7.2 Transition SP_DWS4:Lost1 to SP_DWS5:Lost1Recovered . 160
6.8.7.3 Transition SP_DWS4:Lost1 to SP_DWS6:Lost2. 160
6.8.8 SP_DWS5:Lost1Recovered state. 160
6.8.8.1 State description. 160
6.8.8.2 Transition SP_DWS5:Lost1Recovered to SP_DWS3:SyncAcquired. 161
6.8.8.3 Transition SP_DWS5:Lost1Recovered to SP_DWS6:Lost2 . 161
6.8.9 SP_DWS6:Lost2 state . 161
6.8.9.1 State description. 161
6.8.9.2 Transition SP_DWS6:Lost2 to SP_DWS7:Lost2Recovered . 161
6.8.9.3 Transition SP_DWS6:Lost2 to SP_DWS8:Lost3. 161
6.8.10 SP_DWS7:Lost2Recovered state. 161
6.8.10.1 State description. 161
6.8.10.2 Transition SP_DWS7:Lost2Recovered to SP_DWS4:Lost1 . 161
6.8.10.3 Transition SP_DWS7:Lost2Recovered to SP_DWS8:Lost3 . 161
6.8.11 SP_DWS8:Lost3 state . 161
6.8.11.1 State description. 161
6.8.11.2 Transition SP_DWS8:Lost3 to SP_DWS9:Lost3Recovered . 161
6.8.11.3 Transition SP_DWS8:Lost3 to SP_DWS0:AcquireSync . 161
6.8.12 SP_DWS9:Lost3Recovered state. 162
6.8.12.1 State description. 162
6.8.12.2 Transition SP_DWS9:Lost3Recovered to SP_DWS6:Lost2 . 162
6.8.12.3 Transition SP_DWS9:Lost3Recovered to SP_DWS0:AcquireSync. 162
6.9 Spin-up . 162

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7 Link layer. 163
7.1 Link layer overview. 163
7.2 Primitives. 163
7.2.1 Primitives overview . 163
7.2.2 Primitive summary . 164
7.2.3 Primitive encodings. 168
7.2.4 Primitive sequences. 172
7.2.4.1 Primitive sequences overview. 172
7.2.4.2 Single primitive sequence . 172
7.2.4.3 Repeated primitive sequence. 172
7.2.4.4 Triple primitive sequence . 172
7.2.4.5 Redundant primitive sequence. 173
7.2.5 Primitives not specific to type of connections . 174
7.2.5.1 AIP (Arbitration in progress). 174
7.2.5.2 ALIGN. 175
7.2.5.3 BREAK . 176
7.2.5.4 BROADCAST. 176
7.2.5.5 CLOSE . 176
7.2.5.6 EOAF (End of address frame). 177
7.2.5.7 ERROR . 177
7.2.5.8 HARD_RESET . 177
7.2.5.9 NOTIFY . 177
7.2.5.10 OPEN_ACCEPT. 178
7.2.5.11 OPEN_REJECT . 178
7.2.5.12 SOAF (Start of address frame). 181
7.2.6 Primitives used only inside SSP and SMP connections . 181
7.2.6.1 ACK (Acknowledge) . 181
7.2.6.2 CREDIT_BLOCKED. 181
7.2.6.3 DONE. 181
7.2.6.4 EOF (End of frame). 182
7.2.6.5 NAK (Negative acknowledgement) . 182
7.2.6.6 RRDY (Receiver ready). 182
7.2.6.7 SOF (Start of frame). 182
7.2.7 Primitives used only inside STP co
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