IEC 62541-6:2020
(Main)OPC Unified Architecture - Part 6: Mappings
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.
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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 . 101
– 4 – IEC 62541-6:2020 RLV © IEC 2020
A.1 Attribute Ids . 101
A.2 Status Codes . 101
A.3 Numeric Node Ids . 102
Annex B (normative) OPC UA Nodeset . 103
Annex C (normative) Type declarations for the OPC UA native Mapping . 104
Annex D (normative) WSDL for the XML Mapping . 105
D.1 XML Schema . 105
D.2 WDSL Port Types . 105
D.3 WSDL Bindings . 105
Annex E (normative) Security settings management . 106
E.1 Overview. 106
E.2 SecuredApplication . 107
E.3 CertificateIdentifier . 110
E.4 CertificateStoreIdentifier . 112
E.5 CertificateList . 113
E.6 CertificateValidationOptions . 113
Annex F (normative) Information Model XML Schema . 115
F.1 Overview. 115
F.2 UANodeSet . 115
F.3 UANode . 117
F.4 Reference . 118
F.5 RolePermission . 118
F.6 UAType . 118
F.7 UAInstance . 119
F.8 UAVariable . 119
F.9 UAMethod . 120
F.10 TranslationType . 121
F.11 UADataType . 122
F.12 DataTypeDefinition . 122
F.13 DataTypeField . 123
F.14 Variant . 124
F.15 Example. 125
F.16 UANodeSetChanges . 127
F.17 NodesToAdd . 128
F.18 ReferencesToChange . 128
F.19 ReferenceToChange . 129
F.20 NodesToDelete . 129
F.21 NodeToDelete . 129
F.22 UANodeSetChangesStatus . 130
F.23 NodeSetStatusList . 130
F.24 NodeSetStatus . 131
Bibliography . 132
Figure 1 – The OPC UA Stack Overview . 17
Figure 2 – Encoding Integers in a binary stream . 21
Figure 3 – Encoding Floating Points in a binary stream . 22
Figure 4 – Encoding Strings in a binary stream . 22
Figure 5 – Encoding Guids in a binary stream . 23
Figure 6 – Encoding XmlElement in a binary stream . 24
Figure 7 – A String NodeId . 25
Figure 8 – A Two Byte NodeId . 26
Figure 9 – A Four Byte NodeId . 26
Figure 10 – Security handshake . 57
Figure 11 – OPC UA Secure Conversation MessageChunk . 70
Figure 12 – OPC UA TCP Connection Protocol Message structure . 80
Figure 13 – Client initiated OPC UA Connection Protocol connection . 86
Figure 14 – Server initiated OPC UA Connection Protocol connection . 86
Figure 15 – Closing a OPC UA TCP Connection Protocol connection . 87
Figure 16 – Scenarios for the HTTPS Transport . 94
Figure 17 – Setting up Communication over a WebSocket . 98
Table 1 – Built-in Data Types . 18
Table 2 – Guid structure . 18
Table 3 – Layout of Decimal . 20
Table 4 – Supported Floating Point Types . 22
Table 5 – NodeId components . 24
Table 6 – NodeId DataEncoding values . 25
Table 7 – Standard NodeId Binary DataEncoding . 25
Table 8 – Two Byte NodeId Binary DataEncoding . 26
Table 9 – Four Byte NodeId Binary DataEncoding. 26
Table 10 – ExpandedNodeId Binary DataEncoding . 27
Table 11 – DiagnosticInfo Binary DataEncoding . 28
Table 12 – QualifiedName Binary DataEncoding . 28
Table 13 – LocalizedText Binary DataEncoding . 29
Table 14 – Extension Object Binary DataEncoding. 30
Table 15 – Variant Binary DataEncoding . 31
Table 16 – Data Value Binary DataEncoding . 32
Table 17 – Sample OPC UA Binary Encoded structure . 34
Table 18 – Sample OPC UA Binary Encoded Structure with optional fields . 36
Table 19 – Sample OPC UA Binary Encoded Structure . 37
Table 20 – XML Data Type Mappings for Integers . 39
Table 21 – XML Data Type Mappings for Floating Points . 39
Table 22 – Components of NodeId . 41
Table 23 – Components of ExpandedNodeId . 42
Table 24 – Components of Enumeration . 46
Table 25 – JSON Object Definition for a NodeId . 50
Table 26 – JSON Object Definition for an ExpandedNodeId . 51
Table 27 – JSON Object Definition for a StatusCode . 51
Table 28 – JSON Object Definition for a DiagnosticInfo . 52
Table 29 – JSON Object Definition for a QualifiedName . 52
– 6 – IEC 62541-6:2020 RLV © IEC 2020
Table 30 – JSON Object Definition for a LocalizedText . 52
Table 31 – JSON Object Definition for an ExtensionObject . 53
Table 32 – JSON Object Definition for a Variant . 53
Table 33 – JSON Object Definition for a DataValue . 54
Table 34 – JSON Object Definition for a Decimal . 54
Table 35 – JSON Object Definition for a Structure with Optional Fields . 55
Table 36 – JSON Object Definition for a Union . 56
Table 37 – SecurityPolicy . 58
Table 38 – Application Instance Certificate . 60
Table 39 – Kerberos UserTokenPolicy . 62
Table 40 – JWT UserTokenPolicy . 63
Table 41 – JWT IssuerEndpointUrl Definition . 63
Table 42 – Access Token Claims . 64
Table 43 – OPC UA Secure Conversation Message header . 71
Table 44 – Asymmetric algorithm Security header . 72
Table 45 – Symmetric algorithm Security header . 73
Table 46 – Sequence header . 73
Table 47 – OPC UA Secure Conversation Message footer . 74
Table 48 – OPC UA Secure Conversation Message abort body . 75
Table 49 – OPC UA Secure Conversation OpenSecureChannel Service . 76
Table 50 – PRF inputs for RSA based SecurityPolicies . 78
Table 51 – Cryptography key generation parameters . 78
Table 52 – OPC UA TCP Connection Protocol Message header . 81
Table 53 – OPC UA TCP Connection Protocol Hello Message . 82
Table 54 – OPC UA TCP Connection Protocol Acknowledge Message . 83
Table 55 – OPC UA TCP Connection Protocol Error Message . 83
Table 56 – OPC UA Connection Protocol ReverseHello Message . 84
Table 57 – OPC UA Connection Protocol error codes . 89
Table 58 – WebSocket Protocols Mappings . 98
Table 59 – Well known addresses for Local Discovery Servers . 99
Table A.1 – Identifiers assigned to Attributes . 101
Table E.1 – SecuredApplication . 108
Table E.2 – CertificateIdentifier . 111
Table E.3 – Structured directory store . 112
Table E.4 – CertificateStoreIdentifier . 113
Table E.5 – CertificateList . 113
Table E.6 – CertificateValidationOptions . 114
Table F.1 – UANodeSet . 116
Table F.2 – UANode . 117
Table F.3 – Reference . 118
Table F.4 – RolePermission . 118
Table F.5 – UANodeSet Type Nodes. 118
Table F.6 – UANodeSet Instance Nodes . 119
Table F.7 – UAInstance . 119
Table F.8 – UAVariable . 120
Table F.9 – UAMethod . 120
Table F.10 – TranslationType . 121
Table F.11 – UADataType . 122
Table F.12 – DataTypeDefinition . 122
Table F.13 – DataTypeField . 123
Table F.14 – UANodeSetChanges . 127
Table F.15 – NodesToAdd . 128
Table F.16 – ReferencesToChange . 129
Table F.17 – ReferencesToChange . 129
Table F.18 – NodesToDelete . 129
Table F.19 – ReferencesToChange . 130
Table F.20 – UANodeSetChangesStatus . 130
Table F.21 – NodeSetStatusList . 131
Table F.22 – NodeSetStatus . 131
– 8 – IEC 62541-6:2020 RLV © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPC UNIFIED ARCHITECTURE –
Part 6: Mappings
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.
International Standard IEC 62541-6 has been prepared by subcommittee 65E: Devices and
integration in enterprise systems, of IEC technical committee 65: Industrial-process
measurement, control and automation.
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.
The text of this International Standard is based on the following documents:
FDIS Report on voting
65E/718/FDIS 65E/734/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
Throughout this document and the other parts of IEC 62541, certain document conventions
are used:
Italics are used to denote a defined term or definition that appears in Clause 3 in one of the
parts of the series.
Italics are also used to denote the name of a service input or output parameter or the name of
a structure or element of a structure that are usually defined in tables.
The italicized terms and names are also, with a few exceptions, written in camel-case (the
practice of writing compound words or phrases in which the elements are joined without
spaces, with each element's initial letter capitalized within the compound). For example the
defined term is AddressSpace instead of Address Space. This makes it easier to understand
– 10 – IEC 62541-6:2020 RLV © IEC 2020
that there is a single definition for AddressSpace, not separate definitions for Address and
Space.
A list of all parts of the IEC 62541 series, published under the general title OPC Unified
Architecture, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
OPC UNIFIED ARCHITECTURE –
Part 6: Mappings
1 Scope
This part of IEC 62541 specifies the OPC Unified Architecture (OPC UA) mapping between
the security model described in IEC TR 62541‑2, the abstract service definitions, described
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.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC TR 62541‑1, OPC Unified Architecture – Part 1: Overview and Concepts
IEC TR 62541‑2, OPC Unified Architecture – Part 2: Security Model
IEC 62541‑3, OPC Unified Architecture – Part 3: Address Space Model
IEC 62541‑4, OPC Unified Architecture – Part 4: Services
IEC 62541‑5, OPC Unified Architecture – Part 5: Information Model
IEC 62541‑7, OPC Unified Architecture – Part 7: Profiles
IEC 62541‑12, OPC Unified Architecture – Part 12: Discovery and Global Services
ISO 8601‑1:2019, Date and time – Representations for information interchange – Part 1:
Basic rules
XML Schema Part 1: XML Schema Part 1: Structures
http://www.w3.org/TR/xmlschema-1/
XML Schema Part 2: XML Schema Part 2: Datatypes
http://www.w3.org/TR/xmlschema-2/
SOAP Part 1: SOAP Version 1.2 Part 1: Messaging Framework
http://www.w3.org/TR/soap12-part1/
SOAP Part 2: SOAP Version 1.2 Part 2: Adjuncts
http://www.w3.org/TR/soap12-part2/
XML Encryption: XML Encryption Syntax and Processing
http://www.w3.org/TR/xmlenc-core/
XML Signature: XML-Signature Syntax and Processing
– 12 – IEC 62541-6:2020 RLV © IEC 2020
http://www.w3.org/TR/xmldsig-core/
WS Security: SOAP Message Security 1.1
http://www.oasis-open.org/committees/download.php/16790/wss-v1.1-spec-os-
SOAPMessageSecurity.pdf
WS Addressing: Web Services Addressing (WS-Addressing)
http://www.w3.org/Submission/ws-addressing/
WS Trust: WS Trust 1.3
http://docs.oasis-open.org/ws-sx/ws-trust/v1.3/ws-trust.html
WS Secure Conversation: WS Secure Conversation 1.3
http://docs.oasis-open.org/ws-sx/ws-secureconversation/v1.3/ws-secureconversation.html
WS Security Policy: WS Security Policy 1.2
http://docs.oasis-open.org/ws-sx/ws-securitypolicy/200702/ws-securitypolicy-1.2-spec-
os.html
SSL/TLS: RFC 5246 – The TLS Protocol Version 1.2
http://tools.ietf.org/html/rfc5246.txt
X509: X.509 Public Key Certificate Infrastructure
http://www.itu.int/rec/T-REC-X.509-200003-I/e
WS-I Basic Profile 1.1: WS-I Basic Profile Version 1.1
http://www.ws-i.org/Profiles/BasicProfile-1.1.html
WS-I Basic Security Profile 1.1: WS-I Basic Security Profile Version 1.1
http://www.ws-i.org/Profiles/BasicSecurityProfile-1.1.html
HTTP: RFC 2616 – Hypertext Transfer Protocol – HTTP/1.1
http://www.ietf.org/rfc/rfc2616.txt
Base64: RFC 3548 – The Base16, Base32, and Base64 Data Encodings
http://www.ietf.org/rfc/rfc3548.txt
X690: ITU-T X.690 – Basic (BER), Canonical (CER) and Distinguished (DER) Encoding Rules
http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
IEEE-754: Standard for Binary Floating-Point Arithmetic
http://grouper.ieee.org/groups/754/
HMAC: HMAC – Keyed-Hashing for Message Authentication
http://www.ietf.org/rfc/rfc2104.txt
PKCS #1: PKCS #1 – RSA Cryptography Specifications Version 2.0
http://www.ietf.org/rfc/rfc2437.txt
FIPS 180-2: Secure Hash Standard (SHA)
http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
FIPS 197: Advanced Encyption Standard (AES)
http://www.csrc.nist.gov/publications/fips/fips197/fips-197.pdf
UTF8: UTF-8, a transformation format of ISO 10646
http://tools.ietf.org/html/rfc3629
RFC 3280: RFC 3280 – X.509 Public Key Infrastructure Certificate and CRL Profile
http://www.ietf.org/rfc/rfc3280.txt
RFC 4514: RFC 4514 – LDAP: String Representation of Distinguished Names
http://www.ietf.org/rfc/rfc4514.txt
NTP: RFC 1305 – Network Time Protocol (Version 3)
http://www.ietf.org/rfc/rfc1305.txt
Kerberos: WS Security Kerberos Token Profile 1.1
http://docs.oasis-open.org/wss/v1.1/wss-v1.1-spec-os-KerberosTokenProfile.pdf
XML Schema Part 2: XML Schema Part 2: Datatypes
http://www.w3.org/TR/xmlschema‑2/
SOAP Part 1: SOAP Version 1.2 Part 1: Messaging Framework
http://www.w3.org/TR/soap12‑part1/
SSL/TLS:
...
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
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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 . 79
7.3 SOAP/HTTP . 79
7.4 OPC UA HTTPS . 79
7.4.1 Overview . 79
7.4.2 Session-less Services . 81
7.4.3 XML Encoding . 81
7.4.4 OPC UA Binary Encoding . 82
7.4.5 JSON Encoding . 82
7.5 WebSockets . 83
7.5.1 Overview . 83
7.5.2 Protocol Mapping . 84
7.5.3 Security . 84
7.6 Well known addresses . 85
8 Normative Contracts . 86
8.1 OPC Binary Schema . 86
8.2 XML Schema and WSDL . 86
8.3 Information Model Schema . 86
8.4 Formal definition of UA Information Model. 86
8.5 Constants . 86
8.6 DataType encoding . 86
8.7 Security configuration . 86
Annex A (normative) Constants . 87
A.1 Attribute Ids . 87
– 4 – IEC 62541-6:2020 © IEC 2020
A.2 Status Codes . 87
A.3 Numeric Node Ids . 88
Annex B (normative) OPC UA Nodeset . 89
Annex C (normative) Type declarations for the OPC UA native Mapping . 90
Annex D (normative) WSDL for the XML Mapping . 91
D.1 XML Schema . 91
D.2 WDSL Port Types . 91
D.3 WSDL Bindings . 91
Annex E (normative) Security settings management . 92
E.1 Overview. 92
E.2 SecuredApplication . 93
E.3 CertificateIdentifier . 96
E.4 CertificateStoreIdentifier . 98
E.5 CertificateList . 99
E.6 CertificateValidationOptions . 99
Annex F (normative) Information Model XML Schema . 101
F.1 Overview. 101
F.2 UANodeSet . 101
F.3 UANode . 103
F.4 Reference . 104
F.5 RolePermission . 104
F.6 UAType . 104
F.7 UAInstance . 105
F.8 UAVariable . 105
F.9 UAMethod . 106
F.10 TranslationType . 106
F.11 UADataType . 107
F.12 DataTypeDefinition . 108
F.13 DataTypeField . 108
F.14 Variant . 109
F.15 Example. 110
F.16 UANodeSetChanges . 112
F.17 NodesToAdd . 113
F.18 ReferencesToChange . 113
F.19 ReferenceToChange . 114
F.20 NodesToDelete . 114
F.21 NodeToDelete . 114
F.22 UANodeSetChangesStatus . 115
F.23 NodeSetStatusList . 115
F.24 NodeSetStatus . 115
Bibliography . 117
Figure 1 – The OPC UA Stack Overview . 15
Figure 2 – Encoding Integers in a binary stream . 20
Figure 3 – Encoding Floating Points in a binary stream . 20
Figure 4 – Encoding Strings in a binary stream . 21
Figure 5 – Encoding Guids in a binary stream . 22
Figure 6 – Encoding XmlElement in a binary stream . 22
Figure 7 – A String NodeId . 23
Figure 8 – A Two Byte NodeId . 24
Figure 9 – A Four Byte NodeId . 24
Figure 10 – Security handshake . 55
Figure 11 – OPC UA Secure Conversation MessageChunk . 63
Figure 12 – OPC UA Connection Protocol Message structure . 72
Figure 13 – Client initiated OPC UA Connection Protocol connection . 76
Figure 14 – Server initiated OPC UA Connection Protocol connection . 76
Figure 15 – Closing a OPC UA Connection Protocol connection . 77
Figure 16 – Scenarios for the HTTPS Transport . 80
Figure 17 – Setting up Communication over a WebSocket . 84
Table 1 – Built-in Data Types . 16
Table 2 – Guid structure . 17
Table 3 – Layout of Decimal . 19
Table 4 – Supported Floating Point Types . 20
Table 5 – NodeId components . 22
Table 6 – NodeId DataEncoding values . 23
Table 7 – Standard NodeId Binary DataEncoding . 23
Table 8 – Two Byte NodeId Binary DataEncoding . 24
Table 9 – Four Byte NodeId Binary DataEncoding. 24
Table 10 – ExpandedNodeId Binary DataEncoding . 25
Table 11 – DiagnosticInfo Binary DataEncoding . 26
Table 12 – QualifiedName Binary DataEncoding . 26
Table 13 – LocalizedText Binary DataEncoding . 27
Table 14 – Extension Object Binary DataEncoding. 28
Table 15 – Variant Binary DataEncoding . 29
Table 16 – Data Value Binary DataEncoding . 30
Table 17 – Sample OPC UA Binary Encoded structure . 32
Table 18 – Sample OPC UA Binary Encoded Structure with optional fields . 34
Table 19 – Sample OPC UA Binary Encoded Structure . 35
Table 20 – XML Data Type Mappings for Integers . 37
Table 21 – XML Data Type Mappings for Floating Points . 37
Table 22 – Components of NodeId . 39
Table 23 – Components of ExpandedNodeId . 40
Table 24 – Components of Enumeration . 44
Table 25 – JSON Object Definition for a NodeId . 48
Table 26 – JSON Object Definition for an ExpandedNodeId . 49
Table 27 – JSON Object Definition for a StatusCode . 49
Table 28 – JSON Object Definition for a DiagnosticInfo . 50
Table 29 – JSON Object Definition for a QualifiedName . 50
Table 30 – JSON Object Definition for a LocalizedText . 50
– 6 – IEC 62541-6:2020 © IEC 2020
Table 31 – JSON Object Definition for an ExtensionObject . 51
Table 32 – JSON Object Definition for a Variant . 51
Table 33 – JSON Object Definition for a DataValue . 52
Table 34 – JSON Object Definition for a Decimal . 52
Table 35 – JSON Object Definition for a Structure with Optional Fields . 53
Table 36 – JSON Object Definition for a Union . 54
Table 37 – SecurityPolicy . 56
Table 38 – Application Instance Certificate . 57
Table 39 – Kerberos UserTokenPolicy . 59
Table 40 – JWT UserTokenPolicy . 59
Table 41 – JWT IssuerEndpointUrl Definition . 60
Table 42 – Access Token Claims . 61
Table 43 – OPC UA Secure Conversation Message header . 63
Table 44 – Asymmetric algorithm Security header . 64
Table 45 – Symmetric algorithm Security header . 65
Table 46 – Sequence header . 65
Table 47 – OPC UA Secure Conversation Message footer . 66
Table 48 – OPC UA Secure Conversation Message abort body . 67
Table 49 – OPC UA Secure Conversation OpenSecureChannel Service . 68
Table 50 – PRF inputs for RSA based SecurityPolicies . 70
Table 51 – Cryptography key generation parameters . 70
Table 52 – OPC UA Connection Protocol Message header . 72
Table 53 – OPC UA Connection Protocol Hello Message . 73
Table 54 – OPC UA Connection Protocol Acknowledge Message . 74
Table 55 – OPC UA Connection Protocol Error Message . 74
Table 56 – OPC UA Connection Protocol ReverseHello Message . 75
Table 57 – OPC UA Connection Protocol error codes . 78
Table 58 – WebSocket Protocols Mappings . 84
Table 59 – Well known addresses for Local Discovery Servers . 85
Table A.1 – Identifiers assigned to Attributes . 87
Table E.1 – SecuredApplication . 94
Table E.2 – CertificateIdentifier . 97
Table E.3 – Structured directory store . 98
Table E.4 – CertificateStoreIdentifier . 99
Table E.5 – CertificateList . 99
Table E.6 – CertificateValidationOptions . 100
Table F.1 – UANodeSet . 102
Table F.2 – UANode . 103
Table F.3 – Reference . 104
Table F.4 – RolePermission . 104
Table F.5 – UANodeSet Type Nodes. 104
Table F.6 – UANodeSet Instance Nodes . 105
Table F.7 – UAInstance . 105
Table F.8 – UAVariable . 106
Table F.9 – UAMethod . 106
Table F.10 – TranslationType . 107
Table F.11 – UADataType . 108
Table F.12 – DataTypeDefinition . 108
Table F.13 – DataTypeField . 109
Table F.14 – UANodeSetChanges . 112
Table F.15 – NodesToAdd . 113
Table F.16 – ReferencesToChange . 113
Table F.17 – ReferencesToChange . 114
Table F.18 – NodesToDelete . 114
Table F.19 – ReferencesToChange . 114
Table F.20 – UANodeSetChangesStatus . 115
Table F.21 – NodeSetStatusList . 115
Table F.22 – NodeSetStatus . 116
– 8 – IEC 62541-6:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPC UNIFIED ARCHITECTURE –
Part 6: Mappings
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
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agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62541-6 has been prepared by subcommittee 65E: Devices and
integration in enterprise systems, of IEC technical committee 65: Industrial-process
measurement, control and automation.
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.
The text of this International Standard is based on the following documents:
FDIS Report on voting
65E/718/FDIS 65E/734/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
Throughout this document and the other parts of IEC 62541, certain document conventions
are used:
Italics are used to denote a defined term or definition that appears in Clause 3 in one of the
parts of the series.
Italics are also used to denote the name of a service input or output parameter or the name of
a structure or element of a structure that are usually defined in tables.
The italicized terms and names are also, with a few exceptions, written in camel-case (the
practice of writing compound words or phrases in which the elements are joined without
spaces, with each element's initial letter capitalized within the compound). For example the
defined term is AddressSpace instead of Address Space. This makes it easier to understand
that there is a single definition for AddressSpace, not separate definitions for Address and
Space.
A list of all parts of the IEC 62541 series, published under the general title OPC Unified
Architecture, can be found on the IEC website.
– 10 – IEC 62541-6:2020 © IEC 2020
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
OPC UNIFIED ARCHITECTURE –
Part 6: Mappings
1 Scope
This part of IEC 62541 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.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC TR 62541‑1, OPC Unified Architecture – Part 1: Overview and Concepts
IEC TR 62541‑2, OPC Unified Architecture – Part 2: Security Model
IEC 62541‑3, OPC Unified Architecture – Part 3: Address Space Model
IEC 62541‑4, OPC Unified Architecture – Part 4: Services
IEC 62541‑5, OPC Unified Architecture – Part 5: Information Model
IEC 62541‑7, OPC Unified Architecture – Part 7: Profiles
IEC 62541‑12, OPC Unified Architecture – Part 12: Discovery and Global Services
ISO 8601‑1:2019, Date and time – Representations for information interchange – Part 1:
Basic rules
XML Schema Part 2: XML Schema Part 2: Datatypes
http://www.w3.org/TR/xmlschema‑2/
SOAP Part 1: SOAP Version 1.2 Part 1: Messaging Framework
http://www.w3.org/TR/soap12‑part1/
SSL/TLS: RFC 5246 – The TLS Protocol Version 1.2
http://tools.ietf.org/html/rfc5246.txt
X.509 v3: ISO/IEC 9594‑8 (ITU‑T Rec. X.509), Information technology – Open Systems
Interconnection – The Directory: Public‑key and attribute certificate frameworks
HTTP: RFC 2616 – Hypertext Transfer Protocol – HTTP/1.1
http://www.ietf.org/rfc/rfc2616.txt
– 12 – IEC 62541-6:2020 © IEC 2020
HTTPS: RFC 2818 – HTTP Over TLS
http://www.ietf.org/rfc/rfc2818.txt
Base64: RFC 3548 – The Base16, Base32, and Base64 Data Encodings
http://www.ietf.org/rfc/rfc3548.txt
X690: ISO/IEC 8825‑1 (ITU‑T Rec. X.690), Information technology – ASN.1 encoding rules:
Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and
Distinguished Encoding Rules (DER)
IEEE‑754: Standard for Floating
...
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