EN IEC 61158-3-2:2023

SLOVENSKI STANDARD
01-november-2023
Industrijska komunikacijska omrežja - Specifikacije za procesna vodila - 3-2. del:
Definicija opravil na ravni podatkovnih povezav - Elementi tipa 2 (IEC 61158-3-
2:2023)
Industrial communication networks - Fieldbus specifications - Part 3-2: Data-link layer
service definition - Type 2 elements (IEC 61158-3-2:2023)
Industrielle Kommunikationsnetze - Feldbusse - Teil 3-2: Dienstfestlegungen des Data
Link Layer (Sicherungsschicht) - Typ 2-Elemente (IEC 61158-3-2:2023)
Réseaux de communication industriels - Spécifications des bus de terrain - Partie 3-2:
Définition des services de la couche liaison de données - Eléments de type 2 (IEC 61158
-3-2:2023)
Ta slovenski standard je istoveten z: EN IEC 61158-3-2:2023
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.100.20 Podatkovni povezovalni sloj Data link layer
35.110 Omreževanje Networking
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61158-3-2

NORME EUROPÉENNE
EUROPÄISCHE NORM April 2023
ICS 25.040.40; 35.100.20; 35.110 Supersedes EN 61158-3-2:2014;
EN 61158-3-2:2014/A1:2019
English Version
Industrial communication networks - Fieldbus specifications -
Part 3-2: Data-link layer service definition - Type 2 elements
(IEC 61158-3-2:2023)
Réseaux de communication industriels - Spécifications des Industrielle Kommunikationsnetze - Feldbusse - Teil 3-2:
bus de terrain - Partie 3-2: Définition des services de la Dienstfestlegungen des Data Link Layer
couche liaison de données - Eléments de type 2 (Sicherungsschicht) - Typ 2-Elemente
(IEC 61158-3-2:2023) (IEC 61158-3-2:2023)
This European Standard was approved by CENELEC on 2023-04-13. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61158-3-2:2023 E

European foreword
The text of document 65C/1201/FDIS, future edition 3 of IEC 61158-3-2, prepared by SC 65C
"Industrial networks" of IEC/TC 65 "Industrial-process measurement, control and automation" was
submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN IEC 61158-3-2:2023.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2024-01-13
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-04-13
document have to be withdrawn
This document supersedes EN 61158-3-2:2014 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a Standardization Request given to CENELEC by the
European Commission and the European Free Trade Association.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61158-3-2:2023 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 61158-1 NOTE Approved as EN IEC 61158-1
IEC 61158-2 NOTE Approved as EN 61158-2
IEC 61158-5-2 NOTE Approved as EN IEC 61158-5-2
IEC 61158-6-2 NOTE Approved as EN IEC 61158-6-2
IEC 61784-1 (series) NOTE Approved as EN IEC 61784-1 (series)
IEC 61784-2 (series) NOTE Approved as EN IEC 61784-2 (series)

To be published. Stage at time of publication: FprEN IEC 61784-1-X:2023.
To be published. Stage at time of publication: FprEN IEC 61784-2-X:2023.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 61158-4-2 2023 Industrial communication networks - EN IEC 61158-4-2 2023
Fieldbus specifications - Part 4-2: Data-link
layer protocol specification - Type 2
elements
ISO/IEC 7498-1 - Information technology - Open Systems - -
Interconnection - Basic reference model:
The basic model
ISO/IEC 7498-3 - Information technology - Open Systems - -
Interconnection - Basic reference model:
Naming and addressing
ISO/IEC 8886 - Information technology - Open Systems - -
Interconnection - Data link service
definition
ISO/IEC 10731 1994 Information technology - Open Systems - -
Interconnection - Basic Reference Model -
Conventions for the definition of OSI
services
IEC 61158-3-2 ®
Edition 3.0 2023-03
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –

Part 3-2: Data-link layer service definition – Type 2 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.20; 35.110 ISBN 978-2-8322-6558-1

– 2 – IEC 61158-3-2:2023 © IEC 2023
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
1.1 General . 9
1.2 Specifications . 9
1.3 Conformance . 9
2 Normative references . 10
3 Terms, definitions, symbols, abbreviated terms and conventions . 10
3.1 Reference model terms and definitions . 10
3.2 Service convention terms and definitions . 12
3.3 Common data-link service terms and definitions . 12
3.4 Additional Type 2 data-link specific definitions . 14
3.5 Common symbols and abbreviations . 16
3.6 Additional Type 2 symbols and abbreviations . 17
3.7 Common conventions . 17
4 Connection-mode and connectionless-mode data-link service . 18
4.1 Overview. 18
4.1.1 Data transfer services . 18
4.1.2 DL-management services . 22
4.1.3 Timing services . 22
4.2 Facilities of the data-link service . 22
4.3 Model of the data-link service . 23
4.3.1 General . 23
4.3.2 DLS-instance identification . 23
4.3.3 Model of abstract queue concepts . 23
4.3.4 QoS features . 24
4.3.5 DLS-TxStatus . 25
4.3.6 Receive queues . 25
4.4 Sequence of primitives . 25
4.4.1 Constraints on sequence of primitives . 25
4.4.2 Relation of primitives at DLSAPs . 26
4.4.3 Sequence of primitives at one DLSAP. 27
4.5 Connection-mode data transfer . 27
4.5.1 General . 27
4.5.2 Function . 27
4.5.3 Types of primitives and parameters . 27
4.5.4 Sequence of primitives . 29
4.6 Connectionless-mode data transfer . 29
4.6.1 General . 29
4.6.2 Function . 29
4.6.3 Types of primitives and parameters . 30
4.6.4 Sequence of primitives . 32
4.7 Queue maintenance . 32
4.7.1 Function . 32
4.7.2 Types of primitives and parameters . 32
4.7.3 Request primitive . 33
4.7.4 Confirmation primitive . 33

IEC 61158-3-2:2023 © IEC 2023 – 3 –
4.7.5 Sequence of primitives . 33
4.8 Tag filter . 34
4.8.1 Function . 34
4.8.2 Types of primitives and parameters . 34
4.8.3 Sequence of primitives . 35
5 DL-management services . 35
5.1 Sequence of primitives . 35
5.2 Link synchronization . 36
5.2.1 Function . 36
5.2.2 Types of primitives and parameters . 36
5.2.3 Sequence of primitives . 37
5.3 Synchronized parameter change . 37
5.3.1 Function . 37
5.3.2 Types of primitives and parameters . 37
5.3.3 Sequence of primitives . 39
5.4 Event reports . 40
5.4.1 Function . 40
5.4.2 Types of primitives and parameters . 40
5.4.3 Sequence of primitives . 41
5.5 Bad FCS . 41
5.5.1 Function . 41
5.5.2 Types of primitives and parameters . 41
5.5.3 Sequence of primitives . 41
5.6 Current moderator. 42
5.6.1 Function . 42
5.6.2 Types of primitives and parameters . 42
5.6.3 Sequence of primitives . 42
5.7 Enable moderator . 42
5.7.1 Function . 42
5.7.2 Types of primitives and parameters . 42
5.7.3 Sequence of primitives . 43
5.8 Power-up and online . 43
5.8.1 Function . 43
5.8.2 Types of primitives and parameters . 43
5.8.3 Sequence of primitives . 44
5.9 Listen only . 44
5.9.1 Function . 44
5.9.2 Types of primitives and parameters . 45
5.9.3 Sequence of primitives . 45
5.10 Time distribution . 45
5.10.1 Function . 45
5.10.2 Types of primitives and parameters . 45
Bibliography . 48

Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses . 13
Figure 2 – NUT structure . 19
Figure 3 – Medium access during scheduled time . 20
Figure 4 – Medium access during unscheduled time . 21

– 4 – IEC 61158-3-2:2023 © IEC 2023
Figure 5 – Queue model for the peer and multipoint DLS, DLSAPs and their DLCEPs . 22
Figure 6 – Queue model of a multipoint DLS between a sending DLS-user and one or
more receiving DLS-users . 24
Figure 7 – DLS primitive time-sequence diagram . 26
Figure 8 – State transition diagram for sequences of DLS primitives at one DLSAP . 27
Figure 9 – Sequence of primitives for a successful connection-mode transfer . 29
Figure 10 – Sequence of primitives for an unsuccessful connection-mode transfer . 29
Figure 11 – Sequence of primitives for a successful connectionless-mode transfer . 32
Figure 12 – Sequence of primitives for an unsuccessful connectionless-mode transfer . 32
Figure 13 – Sequence of primitives for a queue maintenance request . 34
Figure 14 – Sequence of primitives for a tag filter request . 35
Figure 15 – Sequence of primitives for a local link synchronization . 37
Figure 16 – Sequence of primitives for a DLM-get/set parameters request . 39
Figure 17 – Sequence of primitives for a DLM-tMinus change request . 39
Figure 18 – Sequence of primitives for a DLM-event indication . 41
Figure 19 – Sequence of primitives for a DLM-bad-FCS indication . 42
Figure 20 – Sequence of primitives for a DLM-current-moderator indication . 42
Figure 21 – Sequence of primitives for a DLM-enable-moderator request. 43
Figure 22 – Sequence of primitives for a DLM-power-up indication . 44
Figure 23 – Sequence of primitives for a DLM-online request . 44
Figure 24 – Sequence of primitives for a DLM-listen-only request . 45

Table 1 – Summary of connection-mode and connectionless-mode primitives and

parameters . 26
Table 2 – DL-connection-mode transfer primitives and parameters . 28
Table 3 – DL-connectionless-mode transfer primitives and parameters . 30
Table 4 – Fixed tag services available to the DLS-user . 31
Table 5 – DL-queue maintenance primitives and parameters (single flush) . 33
Table 6 – DL-queue maintenance primitives and parameters (flush by QoS) . 33
Table 7 – DL-connectionless-mode tag filter primitives and parameters . 34
Table 8 – Summary of DL-management primitives and parameters . 36
Table 9 – Link synchronization primitives and parameters . 37
Table 10 – Synchronized parameter change primitives and parameters (set
configuration) . 38
Table 11 – Synchronized parameter change primitives and parameters (get
configuration) . 38
Table 12 – Synchronized parameter change primitives and parameters (start

countdown) . 38
Table 13 – Synchronized parameter change primitives and parameters (tMinus) . 38
Table 14 – DLMS-configuration-data . 39
Table 15 – Event report primitives and parameters . 40
Table 16 – DLMS events being reported . 40
Table 17 – Bad FCS primitives and parameters . 41
Table 18 – Current moderator primitives and parameters . 42
Table 19 – Enable moderator primitives and parameters . 43

IEC 61158-3-2:2023 © IEC 2023 – 5 –
Table 20 – Power-up primitives and parameters . 43
Table 21 – Online primitives and parameters . 44
Table 22 – Listen-only primitives and parameters . 45
Table 23 – DLMS time and time quality parameters . 46
Table 24 – Time distribution source quality . 46

– 6 – IEC 61158-3-2:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 3-2: Data-link layer service definition –
Type 2 elements
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, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by 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
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
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.
Attention is drawn to the fact that the use of the associated protocol type is restricted by its
intellectual-property-right holders. In all cases, the commitment to limited release of intellectual-
property-rights made by the holders of those rights permits a layer protocol type to be used with
other layer protocols of the same type, or in other type combinations explicitly
authorized by its intellectual-property-right holders.
NOTE Combinations of protocol types are specified in the IEC 61784-1 series and the IEC 61784-2 series.
IEC 61158-3-2 has been prepared by subcommittee 65C: Industrial networks, of IEC technical
committee 65: Industrial-process measurement, control and automation. It is an International
Standard.
This third edition cancels and replaces the second edition published in 2014 and
Amendment 1:2019. This edition constitutes a technical revision.

IEC 61158-3-2:2023 © IEC 2023 – 7 –
This edition includes the following significant technical changes with respect to the previous
edition:
a) update of normative and bibliographic references;
b) use of more inclusive terminology ("master" replaced by "active" or "supervisor");
c) miscellaneous editorial corrections.
The text of this International Standard is based on the following documents:
Draft Report on voting
65C/1201/FDIS 65C/1242/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all the parts of the IEC 61158 series, under the general title Industrial communication
networks – Fieldbus specifications, can be found on the IEC web site.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under 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.
– 8 – IEC 61158-3-2:2023 © IEC 2023
INTRODUCTION
This part of IEC 61158 is one of a series produced to facilitate the interconnection of automation
system components. It is related to other standards in the set as defined by the "three-layer"
fieldbus reference model described in IEC 61158-1.
Throughout the set of fieldbus standards, the term "service" refers to the abstract capability
provided by one layer of the OSI Basic Reference Model to the layer immediately above. Thus,
the data-link layer service defined in this document is a conceptual architectural service,
independent of administrative and implementation divisions.

IEC 61158-3-2:2023 © IEC 2023 – 9 –
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 3-2: Data-link layer service definition –
Type 2 elements
1 Scope
1.1 General
This part of IEC 61158 provides common elements for basic time-critical messaging
communications between devices in an automation environment. The term "time-critical" is used
to represent the presence of a time-window, within which one or more specified actions are
required to be completed with some defined level of certainty. Failure to complete specified
actions within the time window risks failure of the applications requesting the actions, with
attendant risk to equipment, plant and possibly human life.
This document defines in an abstract way the externally visible service provided by the Type 2
fieldbus data-link layer in terms of:
• the primitive actions and events of the service;
• the parameters associated with each primitive action and event, and the form which they
take; and
• the interrelationship between these actions and events, and their valid sequences.
The purpose of this document is to define the services provided to:
• the Type 2 fieldbus application layer at the boundary between the application and data-link
layers of the fieldbus reference model;
• systems management at the boundary between the data-link layer and systems
management of the fieldbus reference model.
Type 2 DL-service provides both a connected and a connectionless subset of those services
specified in ISO/IEC 8886.
1.2 Specifications
The principal objective of this document is to specify the characteristics of conceptual data-link
layer services suitable for time-critical communications and thus supplement the OSI Basic
Reference Model in guiding the development of data-link protocols for time-critical
communications. A secondary objective is to provide migration paths from previously existing
industrial communications protocols.
This document can be used as the basis for formal DL-Programming-Interfaces. Nevertheless,
it is not a formal programming interface, and any such interface will need to address
implementation issues not covered by this specification, including:
• the sizes and octet ordering of various multi-octet service parameters;
• the correlation of paired request and confirm, or indication and response, primitives.
1.3 Conformance
This document does not specify individual implementations or products, nor does it constrain
the implementations of data-link entities within industrial automation systems.

– 10 – IEC 61158-3-2:2023 © IEC 2023
There is no conformance of equipment to this data-link layer service definition standard.
Instead, conformance is achieved through implementation of the corresponding data-link
protocol that fulfills the Type 2 data-link layer services defined in this document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
NOTE All parts of the IEC 61158 series, as well as the IEC 61784-1 series and the IEC 61784-2 series are
maintained simultaneously. Cross-references to these documents within the text therefore refer to the editions as
dated in this list of normative references.
IEC 61158-4-2:2023, Industrial communication networks – Fieldbus specifications – Part 4-2:
Data-link layer protocol specification – Type 2 elements
ISO/IEC 7498-1, Information technology – Open Systems Interconnection – Basic Reference
Model: The Basic Model
ISO/IEC 7498-3, Information technology – Open Systems Interconnection – Basic Reference
Model: Naming and addressing
ISO/IEC 8886, Information technology – Open Systems Interconnection – Data link service
definition
ISO/IEC 10731:1994, Information technology – Open Systems Interconnection – Basic
Reference Model – Conventions for the definition of OSI services
3 Terms, definitions, symbols, abbreviated terms and conventions
For the purposes of this document, the following terms, definitions, symbols, abbreviated terms
and conventions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1 Reference model terms and definitions
This document is based in part on the concepts developed in ISO/IEC 7498-1 and
ISO/IEC 7498-3, and makes use of the following terms defined therein:

IEC 61158-3-2:2023 © IEC 2023 – 11 –
3.1.1 DL-address [ISO/IEC 7498-3]
3.1.2 DL-address-mapping [ISO/IEC 7498-1]
3.1.3 called-DL-address [ISO/IEC 7498-3]
3.1.4 calling-DL-address [ISO/IEC 7498-3]
3.1.5 centralized multi-end-point-connection [ISO/IEC 7498-1]
3.1.6 DL-connection [ISO/IEC 7498-1]
3.1.7 DL-connection-end-point [ISO/IEC 7498-1]
3.1.8 DL-connection-end-point-identifier [ISO/IEC 7498-1]
3.1.9 DL-connection-mode transmission [ISO/IEC 7498-1]
3.1.10 DL-connectionless-mode transmission [ISO/IEC 7498-1]
3.1.11 correspondent (N)-entities [ISO/IEC 7498-1]
correspondent DL-entities (N=2)
correspondent Ph-entities (N=1)
3.1.12 DL-duplex-transmission [ISO/IEC 7498-1]
3.1.13 (N)-entity [ISO/IEC 7498-1]
DL-entity (N=2)
Ph-entity (N=1)
3.1.14 DL-facility [ISO/IEC 7498-1]
3.1.15 flow control [ISO/IEC 7498-1]
3.1.16 (N)-layer [ISO/IEC 7498-1]
DL-layer (N=2)
Ph-layer (N=1)
3.1.17 layer-management [ISO/IEC 7498-1]
3.1.18 DL-local-view [ISO/IEC 7498-3]
3.1.19 DL-name [ISO/IEC 7498-3]
3.1.20 naming-(addressing)-domain [ISO/IEC 7498-3]
3.1.21 peer-entities [ISO/IEC 7498-1]
3.1.22 primitive name [ISO/IEC 7498-3]
3.1.23 DL-protocol [ISO/IEC 7498-1]
3.1.24 DL-protocol-connection-identifier [ISO/IEC 7498-1]
3.1.25 DL-protocol-data-unit [ISO/IEC 7498-1]
3.1.26 DL-relay [ISO/IEC 7498-1]
3.1.27 reset [ISO/IEC 7498-1]
3.1.28 responding-DL-address [ISO/IEC 7498-3]
3.1.29 routing [ISO/IEC 7498-1]
3.1.30 segmenting [ISO/IEC 7498-1]
3.1.31 (N)-service [ISO/IEC 7498-1]
DL-service (N=2)
Ph-service (N=1)
3.1.32 (N)-service-access-point [ISO/IEC 7498-1]
DL-service-access-point (N=2)
Ph-service-access-point (N=1)
3.1.33 DL-service-access-point-address [ISO/IEC 7498-3]
3.1.34 DL-service-connection-identifier [ISO/IEC 7498-1]
3.1.35 DL-service-data-unit [ISO/IEC 7498-1]
3.1.36 DL-simplex-transmission [ISO/IEC 7498-1]

– 12 – IEC 61158-3-2:2023 © IEC 2023
3.1.37 DL-subsystem [ISO/IEC 7498-1]
3.1.38 systems-management [ISO/IEC 7498-1]
3.1.39 DLS-user-data [ISO/IEC 7498-1]

3.2 Service convention terms and definitions
This document also makes use of the following terms defined in ISO/IEC 10731 as they apply
to the data-link layer:
3.2.1 acceptor
3.2.2 asymmetrical service
3.2.3 confirm (primitive);
requestor.deliver (primitive)
3.2.4 deliver (primitive)
3.2.5 DL-confirmed-facility
3.2.6 DL-facility
3.2.7 DL-local-view
3.2.8 DL-mandatory-facility
3.2.9 DL-non-confirmed-facility
3.2.10 DL-provider-initiated-facility
3.2.11 DL-provider-optional-facility
3.2.12 DL-service-primitive;
primitive
3.2.13 DL-service-provider
3.2.14 DL-service-user
3.2.15 DLS-user-optional-facility
3.2.16 indication (primitive);
acceptor.deliver (primitive)
3.2.17 multi-peer
3.2.18 request (primitive);
requestor.submit (primitive)
3.2.19 requestor
3.2.20 response (primitive);
acceptor.submit (primitive)
3.2.21 submit (primitive)
3.2.22 symmetrical service
3.3 Common data-link service terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE Many definitions are common to more than one protocol Type; they are not necessarily used by all protocol
Types.
IEC 61158-3-2:2023 © IEC 2023 – 13 –
3.3.1
DL-segment
link
local link
single DL-subnetwork in which any of the connected DLEs may communicate directly, without
any intervening DL-relaying, whenever all of those DLEs that are participating in an instance of
communication are simultaneously attentive to the DL-subnetwork during the period(s) of
attempted communication
3.3.2
DLSAP
distinctive point at which DL-services are provided by a single DL-entity to a single higher-layer
entity
Note 1 to entry: This definition, derived from ISO/IEC 7498-1, is repeated here to facilitate understanding of the
critical distinction between DLSAPs and their DL-addresses (see Figure 1).

NOTE 1 DLSAPs and PhSAPs are depicted as ovals spanning the boundary between two adjacent layers.
NOTE 2 DL-addresses are depicted as designating small gaps (points of access) in the DLL portion of a DLSAP.
NOTE 3 A single DL-entity can have multiple DLSAP-addresses and group DL-addresses associated with a single
DLSAP.
Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses
3.3.3
DL(SAP)-address
either an individual DLSAP-address, designating a single DLSAP of a single DLS-user, or a
group DL-address potentially designating multiple DLSAPs, each of a single DLS-user
Note 1 to entry: This terminology is chosen because ISO/IEC 7498-3 does not permit the use of the term DLSAP-
address to designate more than a single DLSAP at a single DLS-user.
3.3.4
(individual) DLSAP-address
DL-address that designates only one DLSAP within the extended link

– 14 – IEC 61158-3-2:2023 © IEC 2023
Note 1 to entry: A single DL-entity may have multiple DLSAP-addresses associated with a single DLSAP.
3.3.5
extended link
DL-subnetwork, consisting of the maximal set of links interconnected by DL-relays, sharing a
single DL-name (DL-address) space, in which any of the connected DL-entities may
communicate, one with another, either directly or with the assistance of one or more of those
intervening DL-relay entities
Note 1 to entry: An extended link may be composed of just a single link.
3.3.6
frame
denigrated synonym for DLPDU
3.3.7
group DL-address
DL-address that potentially designates more than one DLSAP within the extended link
Note 1 to entry: A single DL-entity may have multiple group DL-addresses associated with a single DLSAP. A single
DL-entity also may have a single group DL-address associated with more than one DLSAP.
3.3.8
node
single DL-entity as it appears on one local link
3.3.9
receiving DLS-user
DL-service user that acts as a recipient of DLS-user-data
Note 1 to entry: A DL-service user can be concurrently both a sending and receiving DLS-user.
3.3.10
sending DLS-user
DL-service user that acts as a source of DLS-user-data
3.4 Additional Type 2 data-link specific definitions
3.4.1
application
function or data structure for which data is subscribed or published
3.4.2
behavior
indication of how the object responds to particular events
Note 1 to entry: Its description includes the relationship between attribute values and services.
3.4.3
bridge, DL-router
DL-relay entity which performs selective store-and-forward and routing functions to connect two
or more separate DL-subnetworks (links) to form a unified DL-subnetwork (the extended link)
3.4.4
cyclic
term used to describe events which repeat in a regular and repetitive manner
3.4.5
device
physical hardware connection to the link

IEC 61158-3-2:2023 © IEC 2023 – 15 –
Note 1 to entry: A device may contain more than one node.
3.4.6
DL-subnetwork
series of nodes connected by PhEs and, where appropriate, DL-routers
3.4.7
DLPDU
Data-link Protocol Data unit
Note 1 to entry: A DLPDU consists of a source MAC ID, zero or more Lpackets, and an FCS, as transmitted or
received by an associated PhE.
3.4.8
error
discrepancy between a computed, observed or measured value or condition and the specified
or theoretically correct value or condition
3.4.9
fixed tag
two octet identifier (tag) which identifies a specific service to be performed by either
a) that receiving node on the local link which has a specified MAC ID, or
b) all receiving nodes on the local link
Note 1 to entry: Identification of the target node(s) is included in the two octet tag.
3.4.10
generic tag
three octet identifier (tag) which identifies a specific piece of application information
3.4.11
guardband
time slot allocated for the transmission of the moderator DLPDU
3.4.12
link
collection of nodes with unique MAC IDs
Note 1 to entry: Ph-segments connected by Ph-repeaters make up a link; links connected by DL-routers make up
an extended link (sometimes called a lo
...