ISO/IEC/IEEE 8802-1AS:2014

INTERNATIONAL ISO/IEC/
STANDARD IEEE
8802-1AS
First edition
2014-02-15


Information technology —
Telecommunications and information
exchange between systems — Local and
metropolitan area networks —
Part 1AS:
Timing and synchronization for time-
sensitive applications in bridged local
area networks
Technologies de l'information — Télécommunications et échange
d'information entre systèmes — Réseaux locaux et métropolitains —
Partie 1AS: Temporisation et synchronisation pour les applications
sensibles au temps des réseaux locaux pontés





Reference number
ISO/IEC/IEEE 8802-1AS:2014(E)

©
IEEE 2011

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ISO/IEC/IEEE 8802-1AS:2014(E)
©  IEEE 2011
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ISO/IEC/IEEE 8802-1AS:2014(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
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IEEE Standards documents are developed within the IEEE Societies and the Standards Coordinating
Committees of the IEEE Standards Association (IEEE-SA) Standards Board. The IEEE develops its standards
through a consensus development process, approved by the American National Standards Institute, which
brings together volunteers representing varied viewpoints and interests to achieve the final product. Volunteers
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Association.
ISO/IEC/IEEE 8802-1AS was prepared by the LAN/MAN Standards Committee of the IEEE Computer Society
(as IEEE Std 802.1AS-2011). It was adopted by Joint Technical Committee ISO/IEC JTC 1, Information
technology, Subcommittee SC 6, Telecommunications and information exchange between systems, in parallel
with its approval by the ISO/IEC national bodies, under the “fast-track procedure” defined in the Partner
Standards Development Organization cooperation agreement between ISO and IEEE. IEEE is responsible for
the maintenance of this document with participation and input from ISO/IEC national bodies.
ISO/IEC/IEEE 8802 consists of the following parts, under the general title Information technology —
Telecommunications and information exchange between systems — Local and metropolitan area networks:
— Part 11: Wireless LAN medium access control (MAC) and physical layer (PHY) specifications
— Part 1X: Port-based network access control
— Part 1AB: Station and media access control connectivity discovery
— Part 1AE: Media access control (MAC) security
— Part 1AR: Secure device identity
— Part 1AS: Timing and synchronization for time-sensitive applications in bridged local area networks
© IEEE 2011 – All rights reserved iii

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ISO/IEC/IEEE 8802-1AS:2014(E)
— Part 15-4: Wireless medium access control (MAC) and physical layer (PHY) specifications for low-rate
wireless personal area networks (WPANs)

iv © IEEE 2011 – All rights reserved

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ISO/IEC/IEEE 8802-1AS:2014(E)
™
IEEE Std 802.1AS -2011
IEEE Standard for
Local and metropolitan area networks—
Timing and Synchronization for
Time-Sensitive Applications in
Bridged Local Area Networks
Sponsor
LAN/MAN Standards Committee
of the
IEEE Computer Society
Approved 10 February 2011
IEEE SA-Standards Board
© IEEE 2011 – All rights reserved v

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ISO/IEC/IEEE 8802-1AS:2014(E)
Abstract: This standard defines a protocol and procedures for the transport of timing over bridged
and virtual bridged local area networks. It includes the transport of synchronized time, the selection
of the timing source (i.e., best master), and the indication of the occurrence and magnitude of timing
impairments (i.e., phase and frequency discontinuities).
Keywords: best master, frequency offset, grandmaster, IEEE 802.1AS, phase offset,
synchronization, syntonization, time-aware system
The Institute of Electrical and Electronics Engineers, Inc.
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PDF: ISBN 978-0-7381-6536-3 STD97070
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ISO/IEC/IEEE 8802-1AS:2014(E)
IEEE Standards documents are developed within the IEEE Societies and the Standards Coordinating Committees of the
IEEE Standards Association (IEEE-SA) Standards Board. The IEEE develops its standards through a consensus
development process, approved by the American National Standards Institute, which brings together volunteers representing
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ISO/IEC/IEEE 8802-1AS:2014(E)
Introduction
This introduction is not part of IEEE Std 802.1AS-2011, IEEE Standard for Local and metropolitan area networks—
Timing and Synchronization for Time-Sensitive Applications in Bridged Local Area Networks.
This standard specifies the protocol and procedures used to ensure that the synchronization requirements are
met for time-sensitive applications, such as audio and video, across bridged and virtual bridged local area
networks consisting of LAN media where the transmission delays are fixed and symmetrical; for example,
TM
IEEE 802.3 full-duplex links. This includes the maintenance of synchronized time during normal
operation and following addition, removal, or failure of network components and network reconfiguration. It
TM TM
specifies the use of IEEE 1588 specifications where applicable in the context of IEEE Std 802.1D -2004
a
TM
and IEEE Std 802.1Q -2005. Synchronization to an externally provided timing signal (e.g., a recognized
timing standard such as UTC or TAI) is not part of this standard but is not precluded.
This is the first edition of IEEE Std 802.1AS.
This standard contains state-of-the-art material. The area covered by this standard is undergoing evolution.
Revisions are anticipated within the next few years to clarify existing material, to correct possible errors, and
®
to incorporate new related material. Information on the current state of this and other IEEE 802 standards
may be obtained from:
Secretary, IEEE-SA Standards Board
445 Hoes Lane
Piscataway, NJ 08854
USA
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a
Information on references can be found in Clause 2.
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ISO/IEC/IEEE 8802-1AS:2014(E)
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© IEEE 2011 – All rights reserved ix

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ISO/IEC/IEEE 8802-1AS:2014(E)
Contents
1. Overview. 1
1.1 Scope. 1
1.2 Purpose. 2
2. Normative references. 3
3. Definitions . 5
4. Acronyms and abbreviations . 9
5. Conformance. 11
5.1 Requirements terminology. 11
5.2 Protocol Implementation Conformance Statement (PICS). 11
5.3 Time-aware Bridge and end station requirements . 11
5.4 MAC-specific timing and synchronization methods for IEEE 802.3 full-duplex links . 12
5.5 MAC-specific timing and synchronization methods for IEEE Std 802.11-2007 . 12
5.6 MAC-specific timing and synchronization methods for IEEE 802.3 EPON . 12
5.7 MAC-specific timing and synchronization methods for coordinated shared network (CSN). 13
6. Conventions . 15
6.1 General. 15
6.2 Service specification method and notation . 15
6.3 Data types and on-the-wire formats. 15
7. Time synchronization model for a bridged local area network . 19
7.1 General. 19
7.2 Architecture of a time-aware bridged local area network. 19
7.3 Time synchronization . 21
7.4 Time-aware system architecture . 24
7.5 Differences between gPTP and PTP. 25
8. IEEE 802.1AS concepts and terminology . 27
8.1 gPTP domain. 27
8.2 Timescale . 27
8.3 Communication path asymmetry . 28
8.4 Messages. 29
8.5 Ports . 30
8.6 Time-aware system characterization . 32
9. Application interfaces . 37
9.1 Overview of the interfaces. 37
9.2 ClockSourceTime interface . 38
9.3 ClockTargetEventCapture interface . 38
9.4 ClockTargetTriggerGenerate interface . 39
9.5 ClockTargetClockGenerator interface. 40
9.6 ClockTargetPhaseDiscontinuity interface . 41
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ISO/IEC/IEEE 8802-1AS:2014(E)
10. Media-independent layer specification. 43
10.1 Overview. 43
10.2 Time-synchronization state machines. 44
10.3 Best master clock selection and announce interval setting state machines . 67
10.4 Message attributes. 85
10.5 Message formats . 87
10.6 Protocol timing characterization. 95
11. Media-dependent layer specification for full-duplex, point-to-point links. 99
11.1 Overview. 99
11.2 State machines for MD entity specific to full-duplex, point-to-point links. 105
11.3 Message attributes. 122
11.4 Message formats . 124
11.5 Protocol timing characterization. 131
12. Media-dependent layer specification for IEEE 802.11 links. 133
12.1 Overview. 133
12.2 Messages. 135
12.3 Determination of asCapable. 135
12.4 State machines . 136
12.5 Format of VendorSpecific information element. 143
12.6 Synchronization message interval . 144
13. Media-dependent layer specification for interface to IEEE 802.3 Ethernet passive optical
network link . 145
13.1 Overview. 145
13.2 Message attributes. 149
13.3 Message format. 149
13.4 Determination of asCapable. 151
13.5 Layering for IEEE 802.3 EPON links . 151
13.6 Service interface definitions . 152
13.7 MD entity global variables . 154
13.8 State machines . 154
13.9 Message transmission intervals . 158
14. Timing and synchronization management. 159
14.1 General. 159
14.2 Default Parameter Data Set. 159
14.3 Current Parameter Data Set . 161
14.4 Parent Parameter Data Set . 164
14.5 Time Properties Parameter Data Set. 165
14.6 Port Parameter Data Set. 166
14.7 Port Parameter Statistics . 170
14.8 Acceptable Master Table Parameter Data Set . 173
15. Managed object definitions. 175
15.1 Internet Standard Management Framework . 175
15.2 Structure of the MIB . 175
15.3 Security considerations .
...