IEC 61588:2021

Precision Clock Synchronization Protocol for Networked Measurement and Control Systems

IEC 61588:2021 defines a network protocol, the Precision Time Protocol (PTP), enabling accurate and precise synchronization of the real-time clocks of devices in networked distributed systems. The protocol is applicable to systems where devices communicate via networks, including Ethernet. The standard allows multicast communication, unicast communication or both. The standard specifies requirements for mapping the protocol to specific network implementations and defines such mappings, including User Datagram Protocol (UDP)/Internet Protocol (IP versions 4 and 6), and layer-2 IEEE 802.3 Ethernet.

General Information

• Status: Published
• Publication Date: 07-Jun-2021
• ICS: 43.060.50 - Electrical and electronic equipment. Control systems
• Technical Committee: SC 65C - Industrial networks
• Current Stage: PPUB - Publication issued
• Start Date: 28-May-2021
• Completion Date: 08-Jun-2021

Relations

• Revises: IEC 61588:2009 - Precision clock synchronization protocol for networked measurement and control systems
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61588 ®
Edition 3.0 2021-06
™
IEEE Std 1588
INTERNATIONAL
STANDARD
Precision Clock Synchronization Protocol for Networked Measurement and
Control Systems
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IEC 61588 ®
Edition 3.0 2021-06
IEEE Std 1588™
INTERNATIONAL
STANDARD
Precision Clock Synchronization Protocol for Networked Measurement and

Control Systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.110; 35.240.50 ISBN 978-2-8322-9811-4

IEEE Std 1588™-2019 – i –
Contents
1. Scope . 14
2. Normative references . 15
3. Definitions, acronyms, and abbreviations. 16
3.1 Definitions . 16
3.2 Acronyms and abbreviations . 24
4. Conventions . 26
4.1 Descriptive lexical form syntax . 26
4.2 Word usage . 27
4.3 Behavioral specification notation . 28
5. Data types and on-the-wire formats . 30
5.1 General . 30
5.2 Primitive data type specifications . 30
5.3 Derived data type specifications . 31
5.4 On-the-wire formats . 35
6. Clock synchronization model . 36
6.1 General requirements on implementations . 36
6.2 Principal assumptions about the network and implementation recommendations . 39
6.3 PTP Networks . 39
6.4 PTP message classes . 40
6.5 PTP device types . 41
6.6 Synchronization overview. 53
6.7 PTP communications overview . 65
7. Characterization of PTP entities . 69
7.1 Domains . 69
7.2 Timescales used in PTP . 72
7.3 PTP communications . 74
7.4 PTP communication media . 81
7.5 PTP Ports . 84
7.6 PTP Instance characterization . 89
7.7 PTP timing characterization . 103
8. PTP data sets. 105
8.1 General specifications for data set members . 105
8.2 Data sets for PTP Instances . 113
8.3 Data sets for Transparent Clocks . 141
8.4 commonMeanLinkDelayService data sets . 144
9. PTP for Ordinary Clocks and Boundary Clocks . 144
9.1 General protocol requirements for PTP Ordinary Clocks and Boundary Clocks . 144
9.2 State protocol . 145
9.3 Best master clock algorithms . 154
9.4 Grandmaster PTP Instance timePropertiesDS updates . 164
9.5 PTP message processing semantics . 166
9.6 Changes in the PTP Instance . 182
10. PTP for Transparent Clocks . 182
10.1 Requirements for both end-to-end and peer-to-peer Transparent Clocks . 182
10.2 End-to-end Transparent Clock requirements . 182
10.3 Peer-to-peer Transparent Clock requirements . 191
11. Clock offset, path delay, residence time, and asymmetry corrections . 195

Published by IEC under licence from IEEE. © 2019 IEEE. All rights reserved.

– ii – IEEE Std 1588™-2019
11.1 General specifications . 195
11.2 Computation of in Ordinary Clocks and Boundary Clocks . 196
11.3 Delay request-response mechanism for Ordinary Clocks and Boundary Clocks . 197
11.4 Peer-to-peer delay mechanism . 199
11.5 MDMI interface and Special Ports . 204
12. Synchronization and syntonization of clocks . 214
12.1 Clock adjustments . 214
12.2 Syntonization . 214
12.3 Synchronization . 215
13. PTP message formats . 216
13.1 General. 216
13.2 General PTP message format requirements. 216
13.3 Header. 216
13.4 Suffix . 222
13.5 Announce message . 222
13.6 Sync and Delay_Req messages . 224
13.7 Follow_Up message . 224
13.8 Delay_Resp message . 225
13.9 Pdelay_Req message . 225
13.10 Pdelay_Resp message . 226
13.11 Pdelay_Resp_Follow_Up message . 226
13.12 Signaling message . 227
13.13 PTP management message . 228
14. TLV entity specifications . 228
14.1 General requirements . 228
14.2 Propagation of TLVs through Boundary Clocks . 230
14.3 Vendor and standard organization extension TLVs . 231
14.4 PAD TLV (optional) . 233
15. PTP management messages (optional) . 234
15.1 General. 234
15.2 PTP management mechanism . 234
15.3 Processing of PTP management messages . 234
15.4 PTP management message format .
...