IEC 62541-6:2020

OPC Unified Architecture - Part 6: Mappings

IEC 62541-6:2020 specifies the OPC Unified Architecture (OPC UA) mapping between the security model described in IEC TR 62541-2, the abstract service definitions specified in IEC 62541-4, the data structures defined in IEC 62541-5 and the physical network protocols that can be used to implement the OPC UA specification. This third edition cancels and replaces the second edition published in 2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) Encodings:
• added JSON encoding for PubSub (non-reversible);
• added JSON encoding for Client/Server (reversible);
• added support for optional fields in structures;
• added support for Unions.
b) Transport mappings:
• added WebSocket secure connection – WSS;
• added support for reverse connectivity;
• added support for session-less service invocation in HTTPS.
c) Deprecated Transport (missing support on most platforms):
• SOAP/HTTP with WS-SecureConversation (all encodings).
d) Added mapping for JSON Web Token.
e) Added support for Unions to NodeSet Schema.
f) Added batch operations to add/delete nodes to/from NodeSet Schema.
g) Added support for multi-dimensional arrays outside of Variants.
h) Added binary representation for Decimal data types.
i) Added mapping for an OAuth2 Authorization Framework.

Architecture unifiée OPC - Partie 6: Mappings

L'IEC 62541-6:2020 spécifie les mappings de l'Architecture unifiée OPC (OPC UA) entre le modèle de sécurité décrit dans l'IEC TR 62541 2, les définitions de services abstraits spécifiées dans l'IEC 62541 4, les structures de données définies dans l'IEC 62541 5 et les protocoles de réseaux physiques qui peuvent être utilisés pour mettre en œuvre la spécification OPC UA. Cette troisième édition annule et remplace la deuxième édition parue en 2015. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) codages:
• ajout du codage JSON pour PubSub (irréversible);
• ajout du codage JSON pour le Client/Serveur (réversible);
• ajout de la prise en charge des champs facultatifs dans les structures;
• ajout de la prise en charge des Unions;
b) mappings de transport:
• ajout de la connexion sécurisée WebSocket (WSS);
• ajout de la prise en charge de la connectivité inversée;
• ajout de la prise en charge de l'invocation de service sans session dans HTTPS;
c) transport déconseillé (absence de prise en charge sur la plupart des plateformes):
• SOAP/HTTP avec WS-SecureConversation (tous les codages);
d) ajout du mapping pour JSON Web Token;
e) ajout de la prise en charge des Unions pour le Schéma de NodeSet;
f) ajout d'opérations par lots permettant d'ajouter/de supprimer des nœuds au niveau du Schéma de NodeSet;
g) ajout de la prise en charge des matrices multidimensionnelles à l'extérieur des Variantes;
h) ajout d'une représentation binaire pour les types de données Décimaux;
i) ajout du mapping pour le Cadre d'autorisation OAuth2.

General Information

• Status: Published
• Publication Date: 12-Jul-2020
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 25.040.40 - Industrial process measurement and control
• ICS: 35.100.05 - Multilayer applications
• Technical Committee: SC 65E - Devices and integration in enterprise systems
• Drafting Committee: WG 8 - TC 65/SC 65E/WG 8
• Current Stage: PPUB - Publication issued
• Start Date: 31-Jul-2020
• Completion Date: 13-Jul-2020

Relations

• Revises: IEC 62541-6:2015 - OPC unified architecture - Part 6: Mappings
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 62541-6 ®
Edition 3.0 2020-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
OPC unified architecture –
Part 6: Mappings
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
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IEC 62541-6 ®
Edition 3.0 2020-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
OPC unified architecture –
Part 6: Mappings
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.05 ISBN 978-2-8322-8665-4

– 2 – IEC 62541-6:2020 RLV © IEC 2020
CONTENTS
FOREWORD . 8
1 Scope . 11
2 Normative references . 11
3 Terms, definitions, abbreviated terms and symbols . 14
3.1 Terms and definitions . 14
3.2 Abbreviated terms and symbols . 15
4 Overview . 16
5 Data encoding . 17
5.1 General . 17
5.1.1 Overview . 17
5.1.2 Built-in Types . 17
5.1.3 Guid . 18
5.1.4 ByteString . 19
5.1.5 ExtensionObject . 19
5.1.6 Variant . 19
5.1.7 Decimal . 20
5.2 OPC UA Binary . 21
5.2.1 General . 21
5.2.2 Built-in Types . 21
5.2.3 Decimal . 32
5.2.4 Enumerations . 32
5.2.5 Arrays . 32
5.2.6 Structures . 33
5.2.7 Structures with optional fields . 35
5.2.8 Unions . 37
5.2.9 Messages . 38
5.3 OPC UA XML . 39
5.3.1 Built-in Types . 39
5.3.2 Decimal . 45
5.3.3 Enumerations . 45
5.3.4 Arrays . 46
5.3.5 Structures . 46
5.3.6 Structures with optional fields . 47
5.3.7 Unions . 47
5.3.8 Messages . 48
5.4 OPC UA JSON . 48
5.4.1 General . 48
5.4.2 Built-in Types . 49
5.4.3 Decimal . 54
5.4.4 Enumerations . 54
5.4.5 Arrays . 54
5.4.6 Structures . 55
5.4.7 Structures with optional fields . 55
5.4.8 Unions . 56
5.4.9 Messages . 56
6 Message SecurityProtocols . 57

6.1 Security handshake . 57
6.2 Certificates . 59
6.2.1 General . 59
6.2.2 Application Instance Certificate. 59
6.2.3 Signed Software Certificate .
6.2.3 Certificate Chains . 61
6.3 Time synchronization . 61
6.4 UTC and International Atomic Time (TAI) . 62
6.5 Issued User Identity Tokens . 62
6.5.1 Kerberos . 62
6.5.2 JSON Web Token (JWT) . 63
6.5.3 OAuth2 . 63
6.6 WS Secure Conversation . 65
6.7 OPC UA Secure Conversation . 70
6.7.1 Overview . 70
6.7.2 MessageChunk structure . 70
6.7.3 MessageChunks and error handling . 75
6.7.4 Establishing a SecureChannel . 75
6.7.5 Deriving keys . 77
6.7.6 Verifying Message security . 79
7 TransportProtocols . 80
7.1 OPC UA TCP Connection Protocol . 80
7.1.1 Overview . 80
7.1.2 Message structure . 80
7.1.3 Establishing a connection . 84
7.1.4 Closing a connection . 87
7.1.5 Error handling . 87
7.2 OPC UA TCP . 91
7.3 SOAP/HTTP . 91
7.4 OPC UA HTTPS . 93
7.4.1 Overview . 93
7.4.2 Session-less Services . 95
7.4.3 XML Encoding . 95
7.4.4 OPC UA Binary Encoding . 96
7.4.5 JSON Encoding . 97
7.5 WebSockets . 97
7.5.1 Overview . 97
7.5.2 Protocol Mapping . 98
7.5.3 Security . 98
7.6 Well known addresses . 99
8 Normative Contracts . 100
8.1 OPC Binary Schema . 100
8.2 XML Schema and WSDL . 100
8.3 Information Model Schema . 100
8.4 Formal definition of UA Information Model. 100
8.5 Constants . 100
8.6 DataType encoding . 100
8.7 Security configuration . 100
Annex A (normative) Constants .
...

IEC 62541-6 ®
Edition 3.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
OPC unified architecture –
Part 6: Mappings
Architecture unifiée OPC –
Partie 6: Mappings
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
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copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
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Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
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once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
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IEC 62541-6 ®
Edition 3.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
OPC unified architecture –
Part 6: Mappings
Architecture unifiée OPC –
Partie 6: Mappings
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40; 35.100.05 ISBN 978-2-8322-8596-1

– 2 – IEC 62541-6:2020 © IEC 2020
CONTENTS
FOREWORD . 8
1 Scope . 11
2 Normative references . 11
3 Terms, definitions, abbreviated terms and symbols . 13
3.1 Terms and definitions . 13
3.2 Abbreviated terms and symbols . 14
4 Overview . 14
5 Data encoding . 16
5.1 General . 16
5.1.1 Overview . 16
5.1.2 Built-in Types . 16
5.1.3 Guid . 17
5.1.4 ByteString . 17
5.1.5 ExtensionObject . 17
5.1.6 Variant . 18
5.1.7 Decimal . 18
5.2 OPC UA Binary . 19
5.2.1 General . 19
5.2.2 Built-in Types . 19
5.2.3 Decimal . 30
5.2.4 Enumerations . 30
5.2.5 Arrays . 30
5.2.6 Structures . 31
5.2.7 Structures with optional fields . 33
5.2.8 Unions . 35
5.2.9 Messages . 36
5.3 OPC UA XML . 37
5.3.1 Built-in Types . 37
5.3.2 Decimal . 43
5.3.3 Enumerations . 43
5.3.4 Arrays . 44
5.3.5 Structures . 44
5.3.6 Structures with optional fields . 45
5.3.7 Unions . 45
5.3.8 Messages . 46
5.4 OPC UA JSON . 46
5.4.1 General . 46
5.4.2 Built-in Types . 46
5.4.3 Decimal . 52
5.4.4 Enumerations . 52
5.4.5 Arrays . 52
5.4.6 Structures . 53
5.4.7 Structures with optional fields . 53
5.4.8 Unions . 54
5.4.9 Messages . 54
6 Message SecurityProtocols . 55

6.1 Security handshake . 55
6.2 Certificates . 56
6.2.1 General . 56
6.2.2 Application Instance Certificate. 57
6.2.3 Certificate Chains . 58
6.3 Time synchronization . 58
6.4 UTC and International Atomic Time (TAI) . 58
6.5 Issued User Identity Tokens . 58
6.5.1 Kerberos . 58
6.5.2 JSON Web Token (JWT) . 59
6.5.3 OAuth2 . 60
6.6 WS Secure Conversation . 62
6.7 OPC UA Secure Conversation . 62
6.7.1 Overview . 62
6.7.2 MessageChunk structure . 62
6.7.3 MessageChunks and error handling . 67
6.7.4 Establishing a SecureChannel . 67
6.7.5 Deriving keys . 69
6.7.6 Verifying Message security . 70
7 TransportProtocols . 71
7.1 OPC UA Connection Protocol. 71
7.1.1 Overview . 71
7.1.2 Message structure . 72
7.1.3 Establishing a connection . 75
7.1.4 Closing a connection . 77
7.1.5 Error handling . 77
7.2 OPC UA TCP .
...