IEC 61158-3-2:2014
(Main)Industrial communication networks - Fieldbus specifications - Part 3-2: Data-lonk layer service definition - Type 2 elements
Industrial communication networks - Fieldbus specifications - Part 3-2: Data-lonk layer service definition - Type 2 elements
IEC 61158-3-2:2014 defines 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 and 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. This second edition cancels and replaces the first edition published in 2007. It constitutes a technical revision. The main changes are: Correction of references for fixed tag usage in 4.6.3.6. and update of core bibliographic references (original source documents from consortium)
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
L'IEC 61158-3-2:2014 définit les services fournis à la couche application de bus de terrain Type 2 au niveau de la frontière entre les couches application et liaison de données du modèle de référence de bus de terrain et à la gestion des systèmes au niveau de la frontière entre la couche liaison de données et la gestion des systèmes selon le modèle de référence de bus de terrain. Le service DL de type 2 fournit à la fois un sous-ensemble connecté et sans connexion des services spécifiés dans l'ISO/CEI 8886. Cette deuxième édition annule et remplace la première édition parue en 2007. Cette édition constitue une révision technique. Les modifications majeures sont: Correction des références pour l'utilisation des balises fixes en 4.6.3.6. et Mise à jour des principales références bibliographiques (source d'origine - documents du consortium).
General Information
Relations
Overview
IEC 61158-3-2:2014 is an international standard that specifies the data‑link layer services for Type 2 fieldbus protocols used in industrial communication networks. It defines the services presented to the Type 2 application layer at the boundary between the application layer and data‑link layer, and the services between the data‑link layer and systems management. The Type 2 DL‑service includes both connection‑mode and connectionless‑mode subsets (aligned with ISO/IEC 8886). This edition consolidates the 2014 publication and its 2019 amendment (editorial updates and corrections such as fixed tag references).
Key topics and technical requirements
- Data‑link layer service model: Definitions of DLSAPs, addresses, queues and DLCEPs that structure communication between DLS‑users.
- Transfer modes: Clear distinction and service primitives for connection‑mode (reliable, sequenced) and connectionless‑mode (unconfirmed, multicast/peer) data transfer.
- Service primitives and sequences: Time‑sequence diagrams and primitive sets governing request/indication/confirm flows for transfers and management functions.
- Queue maintenance and tag filtering: Mechanisms for message queuing, priority handling, and fixed tag / tag filtering services for selective delivery.
- DL‑management (DLM) services: Management primitives for link synchronization, synchronized parameter change, event reporting, bad FCS reporting, moderator control, power‑up / online behavior and listen‑only modes.
- Time distribution: Parameters and quality metrics for distributing time across the network to support synchronized operation.
- Conformance and interoperability: Normative references and conformance clauses to ensure consistent implementation across devices.
Applications and who uses it
IEC 61158-3-2 is targeted at professionals implementing, testing or integrating fieldbus and industrial Ethernet systems:
- Industrial automation engineers designing deterministic communications for process and discrete manufacturing.
- Device manufacturers (PLCs, I/O modules, gateways) implementing Type 2 data‑link services.
- System integrators and control system architects ensuring multi‑vendor interoperability.
- Test labs and certification bodies validating conformance to fieldbus service semantics. Typical applications include real‑time control loops, distributed I/O networks, synchronized operations, and systems requiring both multicast and point‑to‑point messaging.
Related standards
- IEC 61158 (other parts) - Fieldbus specification family.
- IEC 61784‑1 / IEC 61784‑2 - Combinations and profiles of protocol types.
- ISO/IEC 8886 - Source for connection/connectionless service definitions referenced by Type 2 DL‑service.
Keywords: IEC 61158-3-2, fieldbus, data‑link layer, Type 2, DL‑service, connection‑mode, connectionless, industrial communication, link synchronization, time distribution, queue maintenance.
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IEC 61158-3-2 ®
Edition 2.1 2019-04
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
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 978-2-8322-6856-8
IEC 61158-3-2 ®
Edition 2.1 2019-04
CONSOLIDATED VERSION
REDLINE VERSION
colour
inside
Industrial communication networks – Fieldbus specifications –
Part 3-2: Data-link layer service definition – Type 2 elements
– 2 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
INTRODUCTION to the Amendment . 6
1 Scope . 7
1.1 General . 7
1.2 Specifications . 7
1.3 Conformance . 7
2 Normative references . 8
3 Terms, definitions, symbols, abbreviations and conventions . 8
3.1 Reference model terms and definitions . 8
3.2 Service convention terms and definitions . 10
3.3 Common data-link service terms and definitions . 11
3.4 Additional Type 2 data-link specific definitions . 12
3.5 Common symbols and abbreviations . 15
3.6 Additional Type 2 symbols and abbreviations . 15
3.7 Common conventions . 15
4 Connection-mode and connectionless-mode data-link service . 16
4.1 Overview . 16
4.2 Facilities of the data-link service . 20
4.3 Model of the data-link service . 21
4.4 Sequence of primitives . 23
4.5 Connection-mode data transfer . 25
4.6 Connectionless-mode data transfer . 27
4.7 Queue maintenance . 30
4.8 Tag filter . 32
5 DL-management services . 33
5.1 Sequence of primitives . 33
5.2 Link synchronization . 34
5.3 Synchronized parameter change . 35
5.4 Event reports . 37
5.5 Bad FCS . 39
5.6 Current moderator . 39
5.7 Enable moderator . 40
5.8 Power-up and online . 41
5.9 Listen only . 42
5.10 Time distribution . 43
Bibliography . 45
Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses . 11
Figure 2 – NUT structure . 18
Figure 3 – Medium access during scheduled time . 18
Figure 4 – Medium access during unscheduled time . 19
Figure 5 – Queue model for the peer and multipoint DLS, DLSAPs and their DLCEPs . 20
Figure 6 – Queue model of a multipoint DLS between a sending DLS-user and one or
more receiving DLS-users . 22
© IEC 2019
Figure 7 – DLS primitive time-sequence diagram . 24
Figure 8 – State transition diagram for sequences of DLS primitives at one DLSAP . 25
Figure 9 – Sequence of primitives for a successful connection-mode transfer . 27
Figure 10 – Sequence of primitives for an unsuccessful connection-mode transfer . 27
Figure 11 – Sequence of primitives for a successful connectionless-mode transfer . 30
Figure 12 – Sequence of primitives for an unsuccessful connectionless-mode transfer . 30
Figure 13 – Sequence of primitives for a queue maintenance request . 32
Figure 14 – Sequence of primitives for a tag filter request. 33
Figure 15 – Sequence of primitives for a local link synchronization . 35
Figure 16 – Sequence of primitives for a DLM-get/set parameters request . 37
Figure 17 – Sequence of primitives for a DLM-tMinus change request . 37
Figure 18 – Sequence of primitives for a DLM-event indication . 39
Figure 19 – Sequence of primitives for a DLM-bad-FCS indication . 39
Figure 20 – Sequence of primitives for a DLM-current-moderator indication . 40
Figure 21 – Sequence of primitives for a DLM-enable-moderator request . 41
Figure 22 – Sequence of primitives for a DLM-power-up indication . 42
Figure 23 – Sequence of primitives for a DLM-online request. 42
Figure 24 – Sequence of primitives for a DLM-listen-only request . 42
Table 1 – Summary of connection-mode and connectionless-mode primitives and
parameters . 24
Table 2 – DL-connection-mode transfer primitives and parameters . 26
Table 3 – DL-connectionless-mode transfer primitives and parameters . 28
Table 4 – Fixed tag services available to the DLS-user . 29
Table 5 – DL-queue maintenance primitives and parameters . 31
Table 6 – DL-connectionless-mode tag filter primitives and parameters . 32
Table 7 – Summary of DL-management primitives and parameters . 34
Table 8 – Link synchronization primitives and parameters . 35
Table 9 – Synchronized parameter change primitives and parameters . 36
Table 10 – DLMS-configuration-data . 36
Table 11 – Event report primitives and parameters . 38
Table 12 – DLMS events being reported . 38
Table 13 – Bad FCS primitives and parameters . 39
Table 14 – Current moderator primitives and parameters . 40
Table 15 – Enable moderator primitives and parameters . 40
Table 16 – Power-up and online primitives and parameters . 41
Table 17 – Listen-only primitives and parameters . 42
Table 18 – DLMS time and time quality parameters . 43
Table 19 – Time distribution source quality . 44
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© IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 3-2: Data-link layer service definition –
Type 2 elements
FOREWORD
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This consolidated version of the official IEC Standard and its amendment has been
prepared for user convenience.
IEC 61158-3-2 edition 2.1 contains the second edition (2014-08) [documents 65C/759/
FDIS and 65C/769/RVD] and its amendment 1 (2019-04) [documents 65C/945/FDIS and
65C/954/RVD].
In this Redline version, a vertical line in the margin shows where the technical content
is modified by amendment 1. Additions are in green text, deletions are in strikethrough
red text. A separate Final version with all changes accepted is available in this
publication.
© IEC 2019
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 IEC 61784-1 and IEC 61784-2.
International Standard IEC 61158-3-2 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
This second edition constitutes a technical revision.
The main changes with respect to the previous edition are listed below.
• Correction of references for fixed tag usage in 4.6.3.6.
• Update of core bibliographic references (original source documents from consortium).
• Miscellaneous editorial corrections.
This publication has been drafted in accordance with ISO/IEC Directives, Part 2.
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 the base publication and its amendment will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
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.
– 6 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
INTRODUCTION
This standard 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 standard is a conceptual architectural service,
independent of administrative and implementation divisions.
INTRODUCTION to the Amendment
Source documents referenced by this standard have been updated, this needs to be reflected
in the corresponding sections of the document.
© IEC 2019
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 standard defines in an abstract way the externally visible service provided by the Type 2
fieldbus data-link layer in terms of:
a) the primitive actions and events of the service;
b) the parameters associated with each primitive action and event, and the form which they
take; and
c) the interrelationship between these actions and events, and their valid sequences.
The purpose of this standard 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 standard 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 specification may 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:
a) the sizes and octet ordering of various multi-octet service parameters;
b) the correlation of paired request and confirm, or indication and response, primitives.
1.3 Conformance
This standard does not specify individual implementations or products, nor does it constrain
the implementations of data-link entities within industrial automation systems.
– 8 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
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 1 data-link layer services defined in this standard.
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.
NOTE All parts of the IEC 61158 series, as well as IEC 61784-1 and IEC 61784-2 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 61158-4-2:2014 2019, 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, abbreviations and conventions
For the purposes of this document, the following terms, definitions, symbols, abbreviations
and conventions apply.
3.1 Reference model terms and definitions
This standard 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:
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]
© IEC 2019
3.1.11 correspondent (N)-entities [ISO/IEC 7498-1]
correspondent DL-entities (N=2)
correspondent Ph-entities (N=1)
[ISO/IEC 7498-1]
3.1.12 DL-duplex-transmission
3.1.13 (N)-entity [ISO/IEC 7498-1]
DL-entity (N=2)
Ph-entity (N=1)
[ISO/IEC 7498-1]
3.1.14 DL-facility
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]
[ISO/IEC 7498-3]
3.1.18 DL-local-view
3.1.19 DL-name [ISO/IEC 7498-3]
[ISO/IEC 7498-3]
3.1.20 naming-(addressing)-domain
3.1.21 peer-entities [ISO/IEC 7498-1]
[ISO/IEC 7498-3]
3.1.22 primitive name
3.1.23 DL-protocol [ISO/IEC 7498-1]
[ISO/IEC 7498-1]
3.1.24 DL-protocol-connection-identifier
3.1.25 DL-protocol-data-unit [ISO/IEC 7498-1]
[ISO/IEC 7498-1]
3.1.26 DL-relay
3.1.27 reset [ISO/IEC 7498-1]
[ISO/IEC 7498-3]
3.1.28 responding-DL-address
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]
[ISO/IEC 7498-1]
3.1.34 DL-service-connection-identifier
3.1.35 DL-service-data-unit [ISO/IEC 7498-1]
[ISO/IEC 7498-1]
3.1.36 DL-simplex-transmission
3.1.37 DL-subsystem [ISO/IEC 7498-1]
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© IEC 2019
3.1.38 systems-management [ISO/IEC 7498-1]
[ISO/IEC 7498-1]
3.1.39 DLS-user-data
3.2 Service convention terms and definitions
This standard 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
© IEC 2019
3.3 Common data-link service terms and definitions
For the purposes of this standard, 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.
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.
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
– 12 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
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
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.
© IEC 2019
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
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 local area network)
3.4.13
Lpacket
well-defined sub-portion of a DLPDU containing (among other things)
a) a fixed tag or a generic tag, and
– 14 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
b) DLS-user data or, when the tag has DL-significance, DL-data
3.4.14
moderator
node with the lowest MAC ID that is responsible for transmitting the moderator DLPDU
3.4.15
moderator DLPDU
DLPDU transmitted by the node with the lowest MAC ID for the purpose of synchronizing the
nodes and distributing the link configuration parameters
3.4.16
multipoint DLC
centralized multi-end-point DL-connection offering DL-simplex-transmission between a single
distinguished DLS-user, known as the publisher or publishing DLS-user, and a set of peer but
undistinguished DLS-users, known collectively as the subscribers or subscribing DLS-users,
where the publishing DLS-user can send to the subscribing DLS-users as a group (but not
individually)
Note 1 to entry: A multipoint DLC always provides asymmetrical service.
3.4.17
node
logical connection to a local link, requiring a single MAC ID
Note 1 to entry: A single physical device may appear as many nodes on the same local link. For the purposes of
this protocol, each node is considered to be a separate DLE.
3.4.18
peer-to-peer DLC
point-to-point DL-connection offering DL-simplex-transmission between a single distinguished
sending DLS-user and a single distinguished receiving DLS-user
Note 1 to entry: A peer-to-peer DLC always provides asymmetrical service.
3.4.19
rogue
node that has received a moderator DLPDU that disagrees with the link configuration currently
used by this node
3.4.20
scheduled
data transfers that occur in a deterministic and repeatable manner on predefined NUTs.
3.4.21
tMinus
number of NUTs before a new set of link configuration parameters are to be used
3.4.22
tone
instant of time which marks the boundary between two NUTs
3.4.23
unscheduled
data transfers that use the remaining allocated time in the NUT after the scheduled transfers
have been completed
© IEC 2019
3.5 Common symbols and abbreviations
NOTE Many symbols and abbreviations are common to more than one protocol Type; they are not necessarily
used by all protocol Types.
DL- Data-link layer (as a prefix)
DLC DL-connection
DLCEP DL-connection-end-point
DLE DL-entity (the local active instance of the data-link layer)
DLL DL-layer
DLPCI DL-protocol-control-information
DLPDU DL-protocol-data-unit
DLM DL-management
DLME DL-management Entity (the local active instance of DL-management)
DLMS DL-management Service
DLS DL-service
DLSAP DL-service-access-point
DLSDU DL-service-data-unit
FIFO First-in first-out (queuing method)
OSI Open systems interconnection
Ph- Physical layer (as a prefix)
PhE Ph-entity (the local active instance of the physical layer)
PhL Ph-layer
QoS Quality of service
3.6 Additional Type 2 symbols and abbreviations
MAC ID DL-address of a node
MDS Medium dependent sublayer
NUT Network (actually, local link) update time
NOTE The use of the term “network” in the preceding definition is maintained for historic reasons, even though
the scope involved is only a portion of a single DL-subnetwork.
r.m.s. root mean square
SMAX MAC ID of the maximum scheduled node
Tx Transmit
TUI Table unique identifier
UCMM Unconnected message manager
UMAX MAC ID of maximum unscheduled node
USR Unscheduled start register
3.7 Common conventions
This standard uses the descriptive conventions given in ISO/IEC 10731.
The service model, service primitives, and time-sequence diagrams used are entirely abstract
descriptions; they do not represent a specification for implementation.
– 16 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
Service primitives, used to represent service user/service provider interactions (see
ISO/IEC 10731), convey parameters that indicate information available in the user/provider
interaction.
This standard uses a tabular format to describe the component parameters of the DLS
primitives. The parameters that apply to each group of DLS primitives are set out in tables
throughout the remainder of this standard. Each table consists of up to six columns,
containing the name of the service parameter, and a column each for those primitives and
parameter-transfer directions used by the DLS:
– the request primitive’s input parameters;
– the request primitive’s output parameters;
– the indication primitive’s output parameters;
– the response primitive’s input parameters; and
– the confirm primitive’s output parameters.
NOTE The request, indication, response and confirm primitives are also known as requestor.submit,
acceptor.deliver, acceptor.submit, and requestor.deliver primitives, respectively (see ISO/IEC 10731).
One parameter (or part of it) is listed in each row of each table. Under the appropriate service
primitive columns, a code is used to specify the type of usage of the parameter on the
primitive and parameter direction specified in the column.
M – parameter is mandatory for the primitive.
U – parameter is a User option, and may or may not be provided depending on
the dynamic usage of the DLS-user. When not provided, a default value for
the parameter is assumed.
C – parameter is conditional upon other parameters or upon the environment
of the DLS-user.
(blank) – parameter is never present.
Some entries are further qualified by items in brackets. These may be:
a) a parameter-specific constraint
(=) indicates that the parameter is semantically equivalent to the parameter in the
service primitive to its immediate left in the table.
b) an indication that some note applies to the entry
(n) indicates that the following note n contains additional information pertaining to the
parameter and its use.
In any particular interface, not all parameters need be explicitly stated. Some may be
implicitly associated with the DLSAP at which the primitive is issued.
In the diagrams which illustrate these interfaces, dashed lines indicate cause-and-effect or
time-sequence relationships, and wavy lines indicate that events are roughly
contemporaneous.
4 Connection-mode and connectionless-mode data-link service
4.1 Overview
4.1.1 Data transfer services
The primary task of a DLE is to determine, in co-operation with other DLEs on the same local
link, the granting of permission to transmit on the medium. At its upper interface, the DLL
provides services to receive and deliver service data units (DLSDUs) for higher level entities.
© IEC 2019
NOTE 1 The following access mechanisms are not visible to the higher level entities. They are described here as
an aid to understanding the purpose and use of DLS parameters and services that are visible to higher layer
entities.
This DLL protocol is based on a fixed repetitive time cycle, called the network update time
(NUT). The NUT is maintained in close synchronism among all nodes on the local link. A node
is not permitted access to transmit if its configured NUT does not agree with the NUT
currently being used on the local link. Different local links within the extended link may have
different NUT durations.
Each node contains its own timer synchronized to the local link’s NUT. Medium access is
determined by local sub-division of the NUT into variable-duration access slots. Access to the
medium is in sequential order based on the MAC ID of the node. Specific behaviors have
been incorporated into the access protocol allowing a node which temporarily assumes a
MAC ID of zero to perform link maintenance. The MAC ID numbers of all nodes on a link are
unique. Any DLE detecting the presence of a MAC ID duplicating its own MAC ID immediately
stops transmitting.
An implicit token passing mechanism is used to grant access to the medium. Each node
monitors the source MAC ID of each DLPDU received. At the end of a DLPDU, each DLE sets
an “implicit token register” to the received source MAC ID + 1. If the implicit token register is
equal to the local MAC ID, then the DLE transmits one DLPDU containing zero or more
Lpackets with data. In all other cases, the node watches for either a new DLPDU from the
node identified by the “implicit token register” or a time-out value if the identified node fails to
transmit. In each case, the “implicit token” is automatically advanced to the next MAC ID. All
nodes have the same value in their “implicit token register” preventing collisions on the
medium.
The time-out period (called the “slot time”) is based on the amount of time required for
a) the current node to hear the end of the transmission from the previous node, and
b) the current node to begin transmitting, and
c) the next node to hear the beginning of the transmission from the current node.
The slot time is adjusted to compensate for the total length of the medium since the
propagation delay of the medium effects the first and last item on the previous list.
NOTE 2 The calculation of slot time is the responsibility of System Management.
Each NUT is divided into three major parts: scheduled, unscheduled, and guardband as
shown in Figure 2. This sequence is repeated in every NUT. The implicit token passing
mechanism is used to grant access to the medium during both the unscheduled and
scheduled intervals.
– 18 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
Data-link layer protocol
Scheduled
Guardband
Network update time (NUT)
Unscheduled
Figure 2 – NUT structure
During the scheduled part of the NUT, each node, starting with node 0 and ending with node
SMAX, gets a chance to transmit time-critical (scheduled) data. SMAX is the MAC ID of the
highest numbered node that has access to the medium during the scheduled part of the NUT.
Every node between 0 and SMAX has only one opportunity to send one DLPDU of scheduled
data in each NUT. The opportunity to access the medium during the scheduled time is the
same for each node in every NUT. This allows data that is transmitted during the scheduled
portion of the NUT to be sent in a predictable and deterministic manner.
Figure 3 shows how the permission to transmit is granted during the scheduled time. The
DLS-user regulates the amount of data that each node may transmit during this scheduled
token pass.
Time
Scheduled
Unscheduled
Guardband
0 0
1 1
2 2
3 3
n
...
IEC 61158-3-2 ®
Edition 2.0 2014-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –
Part 3-2: Data-link layer service definition – Type 2 elements
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
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IEC 61158-3-2 ®
Edition 2.0 2014-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –
Part 3-2: Data-link layer service definition – Type 2 elements
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
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX X
ICS 25.040.40; 35.100.20; 35.110 ISBN 978-2-8322-1711-5
– 2 – IEC 61158-3-2:2014 © IEC 2014
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
1.1 General . 7
1.2 Specifications . 7
1.3 Conformance . 7
2 Normative references . 8
3 Terms, definitions, symbols, abbreviations and conventions . 8
3.1 Reference model terms and definitions . 8
3.2 Service convention terms and definitions . 10
3.3 Common data-link service terms and definitions . 11
3.4 Additional Type 2 data-link specific definitions. 12
3.5 Common symbols and abbreviations . 15
3.6 Additional Type 2 symbols and abbreviations . 15
3.7 Common conventions . 15
4 Connection-mode and connectionless-mode data-link service . 16
4.1 Overview . 16
4.2 Facilities of the data-link service . 20
4.3 Model of the data-link service . 21
4.4 Sequence of primitives . 23
4.5 Connection-mode data transfer . 25
4.6 Connectionless-mode data transfer . 27
4.7 Queue maintenance . 30
4.8 Tag filter . 32
5 DL-management services . 33
5.1 Sequence of primitives . 33
5.2 Link synchronization . 34
5.3 Synchronized parameter change . 35
5.4 Event reports . 37
5.5 Bad FCS . 39
5.6 Current moderator . 39
5.7 Enable moderator . 40
5.8 Power-up and online . 41
5.9 Listen only . 42
5.10 Time distribution . 43
Bibliography . 45
Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses . 11
Figure 2 – NUT structure . 18
Figure 3 – Medium access during scheduled time . 18
Figure 4 – Medium access during unscheduled time . 19
Figure 5 – Queue model for the peer and multipoint DLS, DLSAPs and their DLCEPs . 20
Figure 6 – Queue model of a multipoint DLS between a sending DLS-user and one or
more receiving DLS-users . 22
Figure 7 – DLS primitive time-sequence diagram . 24
Figure 8 – State transition diagram for sequences of DLS primitives at one DLSAP . 25
Figure 9 – Sequence of primitives for a successful connection-mode transfer . 27
Figure 10 – Sequence of primitives for an unsuccessful connection-mode transfer . 27
Figure 11 – Sequence of primitives for a successful connectionless-mode transfer . 30
Figure 12 – Sequence of primitives for an unsuccessful connectionless-mode transfer . 30
Figure 13 – Sequence of primitives for a queue maintenance request . 32
Figure 14 – Sequence of primitives for a tag filter request. 33
Figure 15 – Sequence of primitives for a local link synchronization . 35
Figure 16 – Sequence of primitives for a DLM-get/set parameters request . 37
Figure 17 – Sequence of primitives for a DLM-tMinus change request . 37
Figure 18 – Sequence of primitives for a DLM-event indication . 39
Figure 19 – Sequence of primitives for a DLM-bad-FCS indication . 39
Figure 20 – Sequence of primitives for a DLM-current-moderator indication . 40
Figure 21 – Sequence of primitives for a DLM-enable-moderator request . 41
Figure 22 – Sequence of primitives for a DLM-power-up indication . 42
Figure 23 – Sequence of primitives for a DLM-online request. 42
Figure 24 – Sequence of primitives for a DLM-listen-only request . 42
Table 1 – Summary of connection-mode and connectionless-mode primitives and
parameters . 24
Table 2 – DL-connection-mode transfer primitives and parameters . 26
Table 3 – DL-connectionless-mode transfer primitives and parameters . 28
Table 4 – Fixed tag services available to the DLS-user . 29
Table 5 – DL-queue maintenance primitives and parameters . 31
Table 6 – DL-connectionless-mode tag filter primitives and parameters . 32
Table 7 – Summary of DL-management primitives and parameters . 34
Table 8 – Link synchronization primitives and parameters . 35
Table 9 – Synchronized parameter change primitives and parameters . 36
Table 10 – DLMS-configuration-data . 36
Table 11 – Event report primitives and parameters . 38
Table 12 – DLMS events being reported . 38
Table 13 – Bad FCS primitives and parameters . 39
Table 14 – Current moderator primitives and parameters . 40
Table 15 – Enable moderator primitives and parameters . 40
Table 16 – Power-up and online primitives and parameters . 41
Table 17 – Listen-only primitives and parameters . 42
Table 18 – DLMS time and time quality parameters . 43
Table 19 – Time distribution source quality . 44
– 4 – IEC 61158-3-2:2014 © IEC 2014
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,
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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-
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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 IEC 61784-1 and IEC 61784-2.
International Standard IEC 61158-3-2 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
This second edition cancels and replaces the first edition published in 2007. This edition
constitutes a technical revision.
The main changes with respect to the previous edition are listed below.
• Correction of references for fixed tag usage in 4.6.3.6.
• Update of core bibliographic references (original source documents from consortium).
• Miscellaneous editorial corrections.
The text of this standard is based on the following documents:
FDIS Report on voting
65C/759/FDIS 65C/769/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with ISO/IEC Directives, Part 2.
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 publication will remain unchanged until
the stability dateindicated on the IEC web site under http://webstore.iec.ch in the data related
to the specific publication. At this date, the publication will be:
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 61158-3-2:2014 © IEC 2014
INTRODUCTION
This standard 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 standard is a conceptual architectural service,
independent of administrative and implementation divisions.
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 standard defines in an abstract way the externally visible service provided by the Type 2
fieldbus data-link layer in terms of:
a) the primitive actions and events of the service;
b) the parameters associated with each primitive action and event, and the form which they
take; and
c) the interrelationship between these actions and events, and their valid sequences.
The purpose of this standard 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 standard 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 specification may 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:
a) the sizes and octet ordering of various multi-octet service parameters;
b) the correlation of paired request and confirm, or indication and response, primitives.
1.3 Conformance
This standard does not specify individual implementations or products, nor does it constrain
the implementations of data-link entities within industrial automation systems.
– 8 – IEC 61158-3-2:2014 © IEC 2014
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 1 data-link layer services defined in this standard.
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.
NOTE All parts of the IEC 61158 series, as well as IEC 61784-1 and IEC 61784-2 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 61158-4-2:2014, 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, abbreviations and conventions
For the purposes of this document, the following terms, definitions, symbols, abbreviations
and conventions apply.
3.1 Reference model terms and definitions
This standard 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:
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]
3.1.37 DL-subsystem [ISO/IEC 7498-1]
– 10 – IEC 61158-3-2:2014 © IEC 2014
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 standard 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 standard, 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.
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.
DLS-user-entity
DLS-user-entity
DLS-users
DLSAP DLSAP DLSAP
DLSAP-
address DLSAP-
DLSAP-
group DL-
address
addresses
address
DL-layer
DL-entity
PhSA P PhSA P
Ph-layer
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
– 12 – IEC 61158-3-2:2014 © IEC 2014
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
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
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 local area network)
3.4.13
Lpacket
well-defined sub-portion of a DLPDU containing (among other things)
a) a fixed tag or a generic tag, and
– 14 – IEC 61158-3-2:2014 © IEC 2014
b) DLS-user data or, when the tag has DL-significance, DL-data
3.4.14
moderator
node with the lowest MAC ID that is responsible for transmitting the moderator DLPDU
3.4.15
moderator DLPDU
DLPDU transmitted by the node with the lowest MAC ID for the purpose of synchronizing the
nodes and distributing the link configuration parameters
3.4.16
multipoint DLC
centralized multi-end-point DL-connection offering DL-simplex-transmission between a single
distinguished DLS-user, known as the publisher or publishing DLS-user, and a set of peer but
undistinguished DLS-users, known collectively as the subscribers or subscribing DLS-users,
where the publishing DLS-user can send to the subscribing DLS-users as a group (but not
individually)
Note 1 to entry: A multipoint DLC always provides asymmetrical service.
3.4.17
node
logical connection to a local link, requiring a single MAC ID
Note 1 to entry: A single physical device may appear as many nodes on the same local link. For the purposes of
this protocol, each node is considered to be a separate DLE.
3.4.18
peer-to-peer DLC
point-to-point DL-connection offering DL-simplex-transmission between a single distinguished
sending DLS-user and a single distinguished receiving DLS-user
Note 1 to entry: A peer-to-peer DLC always provides asymmetrical service.
3.4.19
rogue
node that has received a moderator DLPDU that disagrees with the link configuration currently
used by this node
3.4.20
scheduled
data transfers that occur in a deterministic and repeatable manner on predefined NUTs.
3.4.21
tMinus
number of NUTs before a new set of link configuration parameters are to be used
3.4.22
tone
instant of time which marks the boundary between two NUTs
3.4.23
unscheduled
data transfers that use the remaining allocated time in the NUT after the scheduled transfers
have been completed
3.5 Common symbols and abbreviations
NOTE Many symbols and abbreviations are common to more than one protocol Type; they are not necessarily
used by all protocol Types.
DL- Data-link layer (as a prefix)
DLC DL-connection
DLCEP DL-connection-end-point
DLE DL-entity (the local active instance of the data-link layer)
DLL DL-layer
DLPCI DL-protocol-control-information
DLPDU DL-protocol-data-unit
DLM DL-management
DLME DL-management Entity (the local active instance of DL-management)
DLMS DL-management Service
DLS DL-service
DLSAP DL-service-access-point
DLSDU DL-service-data-unit
FIFO First-in first-out (queuing method)
OSI Open systems interconnection
Ph- Physical layer (as a prefix)
PhE Ph-entity (the local active instance of the physical layer)
PhL Ph-layer
QoS Quality of service
3.6 Additional Type 2 symbols and abbreviations
MAC ID DL-address of a node
MDS Medium dependent sublayer
NUT Network (actually, local link) update time
NOTE The use of the term “network” in the preceding definition is maintained for historic reasons, even though
the scope involved is only a portion of a single DL-subnetwork.
r.m.s. root mean square
SMAX MAC ID of the maximum scheduled node
Tx Transmit
TUI Table unique identifier
UCMM
Unconnected message manager
UMAX MAC ID of maximum unscheduled node
USR Unscheduled start register
3.7 Common conventions
This standard uses the descriptive conventions given in ISO/IEC 10731.
The service model, service primitives, and time-sequence diagrams used are entirely abstract
descriptions; they do not represent a specification for implementation.
– 16 – IEC 61158-3-2:2014 © IEC 2014
Service primitives, used to represent service user/service provider interactions (see
ISO/IEC 10731), convey parameters that indicate information available in the user/provider
interaction.
This standard uses a tabular format to describe the component parameters of the DLS
primitives. The parameters that apply to each group of DLS primitives are set out in tables
throughout the remainder of this standard. Each table consists of up to six columns,
containing the name of the service parameter, and a column each for those primitives and
parameter-transfer directions used by the DLS:
– the request primitive’s input parameters;
– the request primitive’s output parameters;
– the indication primitive’s output parameters;
– the response primitive’s input parameters; and
– the confirm primitive’s output parameters.
NOTE The request, indication, response and confirm primitives are also known as requestor.submit,
acceptor.deliver, acceptor.submit, and requestor.deliver primitives, respectively (see ISO/IEC 10731).
One parameter (or part of it) is listed in each row of each table. Under the appropriate service
primitive columns, a code is used to specify the type of usage of the parameter on the
primitive and parameter direction specified in the column.
M – parameter is mandatory for the primitive.
U – parameter is a User option, and may or may not be provided depending on
the dynamic usage of the DLS-user. When not provided, a default value for
the parameter is assumed.
C – parameter is conditional upon other parameters or upon the environment
of the DLS-user.
(blank) – parameter is never present.
Some entries are further qualified by items in brackets. These may be:
a) a parameter-specific constraint
(=) indicates that the parameter is semantically equivalent to the parameter in the
service primitive to its immediate left in the table.
b) an indication that some note applies to the entry
(n) indicates that the following note n contains additional information pertaining to the
parameter and its use.
In any particular interface, not all parameters need be explicitly stated. Some may be
implicitly associated with the DLSAP at which the primitive is issued.
In the diagrams which illustrate these interfaces, dashed lines indicate cause-and-effect or
time-sequence relationships, and wavy lines indicate that events are roughly
contemporaneous.
4 Connection-mode and connectionless-mode data-link service
4.1 Overview
4.1.1 Data transfer services
The primary task of a DLE is to determine, in co-operation with other DLEs on the same local
link, the granting of permission to transmit on the medium. At its upper interface, the DLL
provides services to receive and deliver service data units (DLSDUs) for higher level entities.
NOTE 1 The following access mechanisms are not visible to the higher level entities. They are described here as
an aid to understanding the purpose and use of DLS parameters and services that are visible to higher layer
entities.
This DLL protocol is based on a fixed repetitive time cycle, called the network update time
(NUT). The NUT is maintained in close synchronism among all nodes on the local link. A node
is not permitted access to transmit if its configured NUT does not agree with the NUT
currently being used on the local link. Different local links within the extended link may have
different NUT durations.
Each node contains its own timer synchronized to the local link’s NUT. Medium access is
determined by local sub-division of the NUT into variable-duration access slots. Access to the
medium is in sequential order based on the MAC ID of the node. Specific behaviors have
been incorporated into the access protocol allowing a node which temporarily assumes a
MAC ID of zero to perform link maintenance. The MAC ID numbers of all nodes on a link are
unique. Any DLE detecting the presence of a MAC ID duplicating its own MAC ID immediately
stops transmitting.
An implicit token passing mechanism is used to grant access to the medium. Each node
monitors the source MAC ID of each DLPDU received. At the end of a DLPDU, each DLE sets
an “implicit token register” to the received source MAC ID + 1. If the implicit token register is
equal to the local MAC ID, then the DLE transmits one DLPDU containing zero or more
Lpackets with data. In all other cases, the node watches for either a new DLPDU from the
node identified by the “implicit token register” or a time-out value if the identified node fails to
transmit. In each case, the “implicit token” is automatically advanced to the next MAC ID. All
nodes have the same value in their “implicit token register” preventing collisions on the
medium.
The time-out period (called the “slot time”) is based on the amount of time required for
a) the current node to hear the end of the transmission from the previous node, and
b) the current node to begin transmitting, and
c) the next node to hear the beginning of the transmission from the current node.
The slot time is adjusted to compensate for the total length of the medium since the
propagation delay of the medium effects the first an
...
IEC 61158-3-2 ®
Edition 2.1 2019-04
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
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Industrial communication networks – Fieldbus specifications –
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IEC 61158-3-2 ®
Edition 2.1 2019-04
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Industrial communication networks – Fieldbus specifications –
Part 3-2: Data-link layer service definition – Type 2 elements
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
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40; 35.100.20; 35.110 ISBN 978-2-8322-9171-9
IEC 61158-3-2 ®
Edition 2.1 2019-04
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Industrial communication networks – Fieldbus specifications –
Part 3-2: Data-link layer service definition – Type 2 elements
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
– 2 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
INTRODUCTION to the Amendment . 6
1 Scope . 7
1.1 General . 7
1.2 Specifications . 7
1.3 Conformance . 7
2 Normative references . 8
3 Terms, definitions, symbols, abbreviations and conventions . 8
3.1 Reference model terms and definitions . 8
3.2 Service convention terms and definitions . 10
3.3 Common data-link service terms and definitions . 11
3.4 Additional Type 2 data-link specific definitions . 13
3.5 Common symbols and abbreviations . 15
3.6 Additional Type 2 symbols and abbreviations . 16
3.7 Common conventions . 16
4 Connection-mode and connectionless-mode data-link service . 17
4.1 Overview . 17
4.2 Facilities of the data-link service . 21
4.3 Model of the data-link service . 22
4.4 Sequence of primitives . 24
4.5 Connection-mode data transfer . 26
4.6 Connectionless-mode data transfer . 28
4.7 Queue maintenance . 31
4.8 Tag filter . 33
5 DL-management services . 34
5.1 Sequence of primitives . 34
5.2 Link synchronization . 35
5.3 Synchronized parameter change . 36
5.4 Event reports . 38
5.5 Bad FCS . 40
5.6 Current moderator . 40
5.7 Enable moderator . 41
5.8 Power-up and online . 42
5.9 Listen only . 43
5.10 Time distribution . 44
Bibliography . 46
Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses . 12
Figure 2 – NUT structure . 18
Figure 3 – Medium access during scheduled time . 19
Figure 4 – Medium access during unscheduled time . 20
Figure 5 – Queue model for the peer and multipoint DLS, DLSAPs and their DLCEPs . 21
Figure 6 – Queue model of a multipoint DLS between a sending DLS-user and one or
more receiving DLS-users . 23
© IEC 2019
Figure 7 – DLS primitive time-sequence diagram . 25
Figure 8 – State transition diagram for sequences of DLS primitives at one DLSAP . 26
Figure 9 – Sequence of primitives for a successful connection-mode transfer . 28
Figure 10 – Sequence of primitives for an unsuccessful connection-mode transfer . 28
Figure 11 – Sequence of primitives for a successful connectionless-mode transfer . 31
Figure 12 – Sequence of primitives for an unsuccessful connectionless-mode transfer . 31
Figure 13 – Sequence of primitives for a queue maintenance request . 33
Figure 14 – Sequence of primitives for a tag filter request. 34
Figure 15 – Sequence of primitives for a local link synchronization . 36
Figure 16 – Sequence of primitives for a DLM-get/set parameters request . 38
Figure 17 – Sequence of primitives for a DLM-tMinus change request . 38
Figure 18 – Sequence of primitives for a DLM-event indication . 40
Figure 19 – Sequence of primitives for a DLM-bad-FCS indication . 40
Figure 20 – Sequence of primitives for a DLM-current-moderator indication . 41
Figure 21 – Sequence of primitives for a DLM-enable-moderator request . 42
Figure 22 – Sequence of primitives for a DLM-power-up indication . 43
Figure 23 – Sequence of primitives for a DLM-online request. 43
Figure 24 – Sequence of primitives for a DLM-listen-only request . 43
Table 1 – Summary of connection-mode and connectionless-mode primitives and
parameters . 25
Table 2 – DL-connection-mode transfer primitives and parameters . 27
Table 3 – DL-connectionless-mode transfer primitives and parameters . 29
Table 4 – Fixed tag services available to the DLS-user . 30
Table 5 – DL-queue maintenance primitives and parameters . 32
Table 6 – DL-connectionless-mode tag filter primitives and parameters . 33
Table 7 – Summary of DL-management primitives and parameters . 35
Table 8 – Link synchronization primitives and parameters . 36
Table 9 – Synchronized parameter change primitives and parameters . 37
Table 10 – DLMS-configuration-data . 37
Table 11 – Event report primitives and parameters . 39
Table 12 – DLMS events being reported . 39
Table 13 – Bad FCS primitives and parameters . 40
Table 14 – Current moderator primitives and parameters . 41
Table 15 – Enable moderator primitives and parameters . 41
Table 16 – Power-up and online primitives and parameters . 42
Table 17 – Listen-only primitives and parameters . 43
Table 18 – DLMS time and time quality parameters . 44
Table 19 – Time distribution source quality . 45
– 4 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
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.
This consolidated version of the official IEC Standard and its amendment has been
prepared for user convenience.
IEC 61158-3-2 edition 2.1 contains the second edition (2014-08) [documents
65C/759/FDIS and 65C/769/RVD] and its amendment 1 (2019-04) [documents
65C/945/FDIS and 65C/954/RVD].
In this Redline version, a vertical line in the margin shows where the technical content
is modified by amendment 1. Additions are in green text, deletions are in strikethrough
red text. A separate Final version with all changes accepted is available in this
publication.
© IEC 2019
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 IEC 61784-1 and IEC 61784-2.
International Standard IEC 61158-3-2 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
This second edition constitutes a technical revision.
The main changes with respect to the previous edition are listed below.
• Correction of references for fixed tag usage in 4.6.3.6.
• Update of core bibliographic references (original source documents from consortium).
• Miscellaneous editorial corrections.
This publication has been drafted in accordance with ISO/IEC Directives, Part 2.
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 the base publication and its amendment will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication 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.
– 6 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
INTRODUCTION
This standard 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 standard is a conceptual architectural service,
independent of administrative and implementation divisions.
INTRODUCTION to the Amendment
Source documents referenced by this standard have been updated, this needs to be reflected
in the corresponding sections of the document.
© IEC 2019
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 standard defines in an abstract way the externally visible service provided by the Type 2
fieldbus data-link layer in terms of:
a) the primitive actions and events of the service;
b) the parameters associated with each primitive action and event, and the form which they
take; and
c) the interrelationship between these actions and events, and their valid sequences.
The purpose of this standard 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 standard 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 specification may 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:
a) the sizes and octet ordering of various multi-octet service parameters;
b) the correlation of paired request and confirm, or indication and response, primitives.
1.3 Conformance
This standard does not specify individual implementations or products, nor does it constrain
the implementations of data-link entities within industrial automation systems.
– 8 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
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 1 data-link layer services defined in this standard.
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.
NOTE All parts of the IEC 61158 series, as well as IEC 61784-1 and IEC 61784-2 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 61158-4-2:20142019, 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, abbreviations and conventions
For the purposes of this document, the following terms, definitions, symbols, abbreviations
and conventions apply.
3.1 Reference model terms and definitions
This standard 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 2019
3.1.1 DL-address [ISO/IEC 7498-3]
[ISO/IEC 7498-1]
3.1.2 DL-address-mapping
3.1.3 called-DL-address [ISO/IEC 7498-3]
[ISO/IEC 7498-3]
3.1.4 calling-DL-address
3.1.5 centralized multi-end-point-connection [ISO/IEC 7498-1]
[ISO/IEC 7498-1]
3.1.6 DL-connection
3.1.7 DL-connection-end-point [ISO/IEC 7498-1]
[ISO/IEC 7498-1]
3.1.8 DL-connection-end-point-identifier
3.1.9 DL-connection-mode transmission [ISO/IEC 7498-1]
[ISO/IEC 7498-1]
3.1.10 DL-connectionless-mode transmission
3.1.11 correspondent (N)-entities [ISO/IEC 7498-1]
correspondent DL-entities (N=2)
correspondent Ph-entities (N=1)
[ISO/IEC 7498-1]
3.1.12 DL-duplex-transmission
3.1.13 (N)-entity [ISO/IEC 7498-1]
DL-entity (N=2)
Ph-entity (N=1)
[ISO/IEC 7498-1]
3.1.14 DL-facility
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]
[ISO/IEC 7498-3]
3.1.18 DL-local-view
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]
[ISO/IEC 7498-3]
3.1.22 primitive name
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]
[ISO/IEC 7498-1]
3.1.26 DL-relay
3.1.27 reset [ISO/IEC 7498-1]
[ISO/IEC 7498-3]
3.1.28 responding-DL-address
3.1.29 routing [ISO/IEC 7498-1]
3.1.30 segmenting [ISO/IEC 7498-1]
– 10 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
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]
[ISO/IEC 7498-1]
3.1.34 DL-service-connection-identifier
3.1.35 DL-service-data-unit [ISO/IEC 7498-1]
[ISO/IEC 7498-1]
3.1.36 DL-simplex-transmission
3.1.37 DL-subsystem [ISO/IEC 7498-1]
[ISO/IEC 7498-1]
3.1.38 systems-management
3.1.39 DLS-user-data [ISO/IEC 7498-1]
3.2 Service convention terms and definitions
This standard also makes use of the following terms defined in ISO/IEC 10731 as they apply
to the data-link layer:
© IEC 2019
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 standard, 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.
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
– 12 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
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.
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
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
© IEC 2019
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
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
– 14 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
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 local area network)
3.4.13
Lpacket
well-defined sub-portion of a DLPDU containing (among other things)
a) a fixed tag or a generic tag, and
b) DLS-user data or, when the tag has DL-significance, DL-data
3.4.14
moderator
node with the lowest MAC ID that is responsible for transmitting the moderator DLPDU
3.4.15
moderator DLPDU
DLPDU transmitted by the node with the lowest MAC ID for the purpose of synchronizing the
nodes and distributing the link configuration parameters
3.4.16
multipoint DLC
centralized multi-end-point DL-connection offering DL-simplex-transmission between a single
distinguished DLS-user, known as the publisher or publishing DLS-user, and a set of peer but
undistinguished DLS-users, known collectively as the subscribers or subscribing DLS-users,
where the publishing DLS-user can send to the subscribing DLS-users as a group (but not
individually)
© IEC 2019
Note 1 to entry: A multipoint DLC always provides asymmetrical service.
3.4.17
node
logical connection to a local link, requiring a single MAC ID
Note 1 to entry: A single physical device may appear as many nodes on the same local link. For the purposes of
this protocol, each node is considered to be a separate DLE.
3.4.18
peer-to-peer DLC
point-to-point DL-connection offering DL-simplex-transmission between a single distinguished
sending DLS-user and a single distinguished receiving DLS-user
Note 1 to entry: A peer-to-peer DLC always provides asymmetrical service.
3.4.19
rogue
node that has received a moderator DLPDU that disagrees with the link configuration currently
used by this node
3.4.20
scheduled
data transfers that occur in a deterministic and repeatable manner on predefined NUTs.
3.4.21
tMinus
number of NUTs before a new set of link configuration parameters are to be used
3.4.22
tone
instant of time which marks the boundary between two NUTs
3.4.23
unscheduled
data transfers that use the remaining allocated time in the NUT after the scheduled transfers
have been completed
3.5 Common symbols and abbreviations
NOTE Many symbols and abbreviations are common to more than one protocol Type; they are not necessarily
used by all protocol Types.
DL- Data-link layer (as a prefix)
DLC DL-connection
DLCEP DL-connection-end-point
DLE DL-entity (the local active instance of the data-link layer)
DLL DL-layer
DLPCI DL-protocol-control-information
DLPDU DL-protocol-data-unit
DLM DL-management
DLME DL-management Entity (the local active instance of DL-management)
DLMS DL-management Service
DLS DL-service
DLSAP DL-service-access-point
– 16 – IEC 61158-3-2:2014+AMD1:2019 CSV
© IEC 2019
DLSDU DL-service-data-unit
FIFO First-in first-out (queuing method)
OSI Open systems interconnection
Ph- Physical layer (as a prefix)
PhE Ph-entity (the local active instance of the physical layer)
PhL Ph-layer
QoS Quality of service
3.6 Additional Type 2 symbols and abbreviations
MAC ID DL-address of a node
MDS Medium dependent sublayer
NUT Network (actually, local link) update time
NOTE The use of the term “network” in the preceding definition is maintained for historic reasons, even though
the scope involved is only a portion of a single DL-subnetwork.
r.m.s. root mean square
SMAX MAC ID of the maximum scheduled node
Tx Transmit
TUI Table unique identifier
UCMM Unconnected message manager
UMAX MAC ID of maximum unscheduled node
USR Unscheduled start register
3.7 Common conventions
This standard uses the descriptive conventions given in ISO/IEC 10731.
The service model, service primitives, and time-sequence diagrams used are entirely abstract
descriptions; they do not represent a specification for implementation.
Service primitives, used to represent service user/service provider interactions (see
ISO/IEC 10731), convey parameters that indicate information available in the user/provider
interaction.
This standard uses a tabular format to describe the component parameters of the DLS
primitives. The parameters that apply to each group of DLS primitives are set out in tables
throughout the remainder of this standard. Each table consists of up to six columns,
containing the name of the service parameter, and a column each for those primitives and
parameter-transfer directions used by the DLS:
– the request primitive’s input parameters;
– the request primitive’s output parameters;
– the indication primitive’s output parameters;
– the response primitive’s input parameters; and
– the confirm primitive’s output parameters.
NOTE The request, indication, response and confirm primitives are also known as requestor.submit,
acceptor.deliver, acceptor.submit, and requestor.deliver primitives, respectively (see ISO/IEC 10731).
One parameter (or part of it) is listed in each row of each table. Under the appropriate service
primitive columns, a code is used to specify the type of usage of the parameter on the
primitive and parameter direction specified in the column.
© IEC 2019
M – parameter is mandatory for the primitive.
U – parameter is a User option, and may or may not be provided depending on
the dynamic usage of the DLS-user. When not provided, a default value for
the parameter is assumed.
C – parameter is conditional upon other parameters or upon the environment
of the DLS-user.
(blank) – parameter is never present.
Some entries are further qualified by items in brackets. These may be:
a) a parameter-specific constraint
(=) indicates that the parameter is semantically equivalent to the parameter in the
service primitive to its immediate left in the table.
b) an indication that some note applies to the entry
(n) indicates that the following note n contains additional information pertaining to the
parameter and its use.
In any particular interface, not all parameters need be explicitly stated. Some may be
implicitly associated with the DLSAP at which the primitive is issued.
In the diagrams which illustrate these interfaces, dashed lines indicate cause-and-effect or
time-sequence relationships, and wavy lines indicate that events are roughly
contemporaneous.
4 Connection-mode and connectionless-mode data-link service
4.1 Overview
4.1.1 Data transfer services
The primary task of a DLE is to determine, in co-operation with other DLEs on the same local
link, the granting of permission to transmit on the medium. At its upper interface, the DLL
provides services to receive and deliver service data units (DLSDUs) for higher level entities.
NOTE 1 The following access mechanisms are not visible to the higher level entities. They are described here as
an aid to understanding the purpose and use of DLS parameters and services that are visible to higher layer
entities.
This DLL protocol is based on a fixed repetitive time cycle, called the network update time
(NUT). The NUT is maintained in close synchronism among all nodes on the local link. A node
is not permitted access to transmit if its configured NUT does not agree with the NUT
currently being used on the local link. Different local links within the extended link may have
different NUT durations.
Each node contains its own timer synchronized to the local link’s NUT. Medium access is
determined by local sub-division of the NUT into variable-duration access slots. Access to the
medium is in sequential order based on the MAC ID of the node. Specific behaviors have
been incorporated into the access protocol allowing a node which te
...
Frequently Asked Questions
IEC 61158-3-2:2014 is a standard published by the International Electrotechnical Commission (IEC). Its full title is "Industrial communication networks - Fieldbus specifications - Part 3-2: Data-lonk layer service definition - Type 2 elements". This standard covers: IEC 61158-3-2:2014 defines 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 and 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. This second edition cancels and replaces the first edition published in 2007. It constitutes a technical revision. The main changes are: Correction of references for fixed tag usage in 4.6.3.6. and update of core bibliographic references (original source documents from consortium)
IEC 61158-3-2:2014 defines 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 and 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. This second edition cancels and replaces the first edition published in 2007. It constitutes a technical revision. The main changes are: Correction of references for fixed tag usage in 4.6.3.6. and update of core bibliographic references (original source documents from consortium)
IEC 61158-3-2:2014 is classified under the following ICS (International Classification for Standards) categories: 25.040.40 - Industrial process measurement and control; 35.100.20 - Data link layer; 35.110 - Networking. The ICS classification helps identify the subject area and facilitates finding related standards.
IEC 61158-3-2:2014 has the following relationships with other standards: It is inter standard links to IEC 61158-3-2:2014/AMD1:2019, IEC 61158-3-2:2007, IEC 61158-3-2:2023. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase IEC 61158-3-2:2014 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of IEC standards.
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