IEC 61158-4-14:2010

IEC 61158-4-14 ®
Edition 2.0 2010-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –
Part 4-14: Data-link layer protocol specification – Type 14 elements

Réseaux de communication industriels – Spécifications de bus de terrain –
Partie 4-14: Spécification du protocole de couche de liaison de données –
Eléments de Type 14
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IEC 61158-4-14 ®
Edition 2.0 2010-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –

Part 4-14: Data-link layer protocol specification – Type 14 elements

Réseaux de communication industriels – Spécifications de bus de terrain –

Partie 4-14: Spécification du protocole de couche de liaison de données –

Eléments de Type 14
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
V
CODE PRIX
ICS 25.04.40; 35.100.20; 35.110 ISBN 978-2-88912-859-4

– 2 – 61158-4-14  IEC:2010
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
1.1 General . 7
1.2 Specifications . 7
1.3 Procedures . 7
1.4 Applicability . 8
1.5 Conformance . 8
2 Normative references . 8
3 Terms, definitions, symbols and abbreviations . 8
3.1 Reference model terms and definitions . 9
3.2 Service convention terms and definitions . 11
3.3 ISO/IEC 8802-3 terms . 11
3.4 Common terms and definitions . 12
3.5 Symbols and abbreviations . 15
4 Overview of the DL-protocol . 16
4.1 General . 16
4.2 Services provided by the DL . 17
4.3 Structure of deterministic communication scheduling . 18
5 Procedure of deterministic communication scheduling . 19
5.1 Overview . 19
5.2 State transitions . 20
5.3 State table . 22
5.4 Function descriptions . 23
6 Structure and encoding of ECSME PDU . 27
6.1 ECSME PDU structure . 27
6.2 Encoding of ECSME packet . 29
Bibliography . 32

Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses . 13
Figure 2 – Communication model . 16
Figure 3 – Type 14 packet identifier . 18
Figure 4 – Time-sharing communication scheduling . 18
Figure 5 – State transitions of ECSME . 20
Figure 6 – Format of NonPeriodicDataAnnunciation PDU . 27
Figure 7 – Format of EndofNonPeriodicDataSending PDU . 28
Figure 8 – Format of Type 14 PDU. 28
Figure 9 – Format of Type 14 PDU for FRT application . 28

Table 1 – ECSME state transitions . 22
Table 2 – NonperiodicDataSendingSuc() description . 23
Table 3 – NonperiodicDataAnnunciation() description . 23
Table 4 – NonperiodicDataSending() description . 23
Table 5 – NonperiodicDataSendingSuc() description . 24

61158-4-14  IEC:2010 – 3 –
Table 6 – FirstNonperiodicDataSending() description . 24
Table 7 – NonperiodicDataPriority() description . 24
Table 8 – NonperiodicDataTimeEnough() description . 25
Table 9 – NonperiodicDataSending() description . 25
Table 10 – EndOfNonperiodicDataSending() description . 25
Table 11 – IsDeviceConfigured() description . 26
Table 12 – CountOffsetTime() description . 26
Table 13 – DataSendingTiming() description . 26
Table 14 – RecEndofNonPeriodicDataSending() description . 26
Table 15 – NonPeriodicDataAnnunciation message encoding . 29
Table 16 – EndofNonPeriodicDataSending message encoding . 30
Table 17 – Type 14 DL-management Tag encoding . 30
Table 18 – Type 14 message encoding . 31
Table 19 – Type 14 message for FRT application encoding . 31

– 4 – 61158-4-14  IEC:2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 4-14: Data-link layer protocol specification –
Type 14 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
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6) All users should ensure that they have the latest edition of this publication.
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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.
International Standard IEC 61158-4-14 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:
• Provide stability date for the publication;
• Update the Normative references and Bibliography;
• Corrections the edit error;
• specification changes for CPF3;
– update of the requirements for all conformance classes;
– update of the requirements for all conformance services.

61158-4-14  IEC:2010 – 5 –
This bilingual version published in 2012-01 corresponds to the English version published in
2010-08.
The text of this standard is based on the following documents:
FDIS Report on voting
65C/605/FDIS 65C/619/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.
The French version has not been voted upon.
This publication has been drafted in accordance with ISO/IEC Directives, Part 2.
A list of all the parts of the IEC 61158 series, published 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 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.
NOTE The revision of this standard will be synchronized with the other parts of the IEC 61158 series.

– 6 – 61158-4-14  IEC:2010
INTRODUCTION
This part of IEC 61158 is one of a series produced to facilitate the interconnection of
automation system components. It is related to other standards in the set as defined by the
“three-layer” fieldbus reference model described in IEC 61158-1.
The data-link protocol provides the data-link service by making use of the services available
from the physical layer. The primary aim of this standard is to provide a set of rules for
communication expressed in terms of the procedures to be carried out by peer data-link
entities (DLEs) at the time of communication. These rules for communication are intended to
provide a sound basis for development in order to serve a variety of purposes:
a) as a guide for implementors and designers;
b) for use in the testing and procurement of equipment;
c) as part of an agreement for the admittance of systems into the open systems environment;
d) as a refinement to the understanding of time-critical communications within OSI.
This standard is concerned, in particular, with the communication and interworking of sensors,
effectors and other automation devices. By using this standard together with other standards
positioned within the OSI or fieldbus reference models, otherwise incompatible systems may
work together in any combination.
NOTE Use of some of the associated protocol types is restricted by their 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 particular data-link layer protocol type to be used with physical layer and application layer protocols in Type
combinations as specified explicitly in profile parts. Use of the various protocol types in other combinations may
require permission from their respective intellectual-property-right holders.
The International Electrotechnical Commission (IEC) draws attention to the fact that it is
claimed that compliance with this document may involve the use of a patent concerning Type
14 elements and possibly other types given in subclause 5 as follows:
CN200410088676.7 [SP] Scheduling method with deterministic communication based on
Ethernet
IEC takes no position concerning the evidence, validity and scope of these patent rights.
The holder of this patent right has assured the IEC that he/she is willing to negotiate licences
either free of charge or under reasonable and non-discriminatory terms and conditions with
applicants throughout the world. In this respect, the statement of the holder of this patent right
is registered with IEC. Information may be obtained from:
[SP] Zhejiang SUPCON Technology Co., Ltd.
Dongqin FENG
Liuhe Road 309, Bingjiang District,
Hangzhou, 310053
China
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights other than those identified above. IEC shall not be held responsible for
identifying any or all such patent rights.
ISO (www.iso.org/patents) and IEC (http://www.iec.ch/tctools/patent_decl.htm) maintain on-
line data bases of patents relevant to their standards. Users are encouraged to consult the
data bases for the most up to date information concerning patents.

61158-4-14  IEC:2010 – 7 –
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 4-14: Data-link layer protocol specification –
Type 14 elements
1 Scope
1.1 General
The data-link layer provides basic time-critical messaging communications between devices in
an automation environment.
This protocol provides communication opportunities to all participating data-link entities
a) in a synchronously-starting cyclic manner, according to a pre-established schedule, and
b) in a cyclic or acyclic asynchronous manner, as requested each cycle by each of those
data-link entities.
Thus this protocol can be characterized as one which provides cyclic and acyclic access
asynchronously but with a synchronous restart of each cycle.
1.2 Specifications
This standard specifies
a) procedures for the timely transfer of data and control information from one data-link user
entity to a peer user entity, and among the data-link entities forming the distributed data-
link service provider;
b) procedures for giving communications opportunities to all participating DL-entities,
sequentially and in a cyclic manner for deterministic and synchronized transfer at cyclic
intervals;
c) procedures for giving communication opportunities available for time-critical data
transmission together with non-time-critical data transmission without prejudice to the
time-critical data transmission;
d) procedures for giving cyclic and acyclic communication opportunities for time-critical data
transmission with prioritized access;
e) procedures for giving communication opportunities based on standard ISO/ IEC 8802-3
medium access control, with provisions for nodes to be added or removed during normal
operation;
f) the structure of the fieldbus DLPDUs used for the transfer of data and control information
by the protocol of this standard, and their representation as physical interface data units.
1.3 Procedures
The procedures are defined in terms of
a) the interactions between peer DL-entities (DLEs) through the exchange of fieldbus
DLPDUs;
b) the interactions between a DL-service (DLS) provider and a DLS-user in the same system
through the exchange of DLS primitives;
c) the interactions between a DLS-provider and a Ph-service provider in the same system
through the exchange of Ph-service primitives.

– 8 – 61158-4-14  IEC:2010
1.4 Applicability
These procedures are applicable to instances of communication between systems which
support time-critical communications services within the data-link layer of the OSI or fieldbus
reference models, and which require the ability to interconnect in an open systems
interconnection environment.
Profiles provide a simple multi-attribute means of summarizing an implementation’s
capabilities, and thus its applicability to various time-critical communications needs.
1.5 Conformance
This standard also specifies conformance requirements for systems implementing these
procedures. This standard does not contain tests to demonstrate compliance with such
requirements.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC/TR 61158-1:2010 , Industrial communication networks – Fieldbus specifications – Part 1:
Overview and guidance for the IEC 61158 and IEC 61784 series
IEC 61158-5-14:2010 , Industrial communication networks – Fieldbus specifications – Part 5-
14: Application layer service definition – Type 14 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 8802-3, Information technology – Telecommunications and information exchange
between systems – Local and metropolitan area networks – Specific requirements – Part 3:
Carrier sense multiple access with collision detection (CSMA/CD) access method and
physical layer specifications
ISO/IEC 10731, Information technology – Open Systems Interconnection – Basic Reference
Model – Conventions for the definition of OSI services
IETF RFC 768, User Datagram Protocol (UDP), available at
IETF RFC 791, Internet protocol, available at
3 Terms, definitions, symbols and abbreviations
For the purposes of this document, the following terms, definitions, symbols and abbreviations
apply.
___________
To be published
61158-4-14  IEC:2010 – 9 –
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 called-DL-address [ISO/IEC 7498-3]
3.1.2 calling-DL-address [ISO/IEC 7498-3]
3.1.3 centralized multi-end-point-connection [ISO/IEC 7498-1]
3.1.4 correspondent (N)-entities [ISO/IEC 7498-1]
correspondent DL-entities  (N=2)
correspondent Ph-entities  (N=1)
3.1.5 demultiplexing [ISO/IEC 7498-1]
3.1.6 DL-address [ISO/IEC 7498-3]
3.1.7 DL-address-mapping [ISO/IEC 7498-1]
3.1.8 DL-connection [ISO/IEC 7498-1]
3.1.9 DL-connection-end-point [ISO/IEC 7498-1]
3.1.10 DL-connection-end-point-identifier [ISO/IEC 7498-1]
3.1.11 DL-connection-mode transmission [ISO/IEC 7498-1]
3.1.12 DL-connectionless-mode transmission [ISO/IEC 7498-1]
3.1.13 DL-data-sink
[ISO/IEC 7498-1]
3.1.14 DL-data-source [ISO/IEC 7498-1]
3.1.15 DL-duplex-transmission [ISO/IEC 7498-1]
3.1.16 DL-facility [ISO/IEC 7498-1]
3.1.17 DL-local-view [ISO/IEC 7498-3]
3.1.18 DL-name [ISO/IEC 7498-3]
3.1.19 DL-protocol
[ISO/IEC 7498-1]
3.1.20 DL-protocol-connection-identifier [ISO/IEC 7498-1]
3.1.21 DL-protocol-control-information
[ISO/IEC 7498-1]
3.1.22 DL-protocol-data-unit [ISO/IEC 7498-1]
3.1.23 DL-protocol-version-identifier [ISO/IEC 7498-1]
3.1.24 DL-relay [ISO/IEC 7498-1]
3.1.25 DL-service-connection-identifier
[ISO/IEC 7498-1]
3.1.26 DL-service-data-unit [ISO/IEC 7498-1]
3.1.27 DL-simplex-transmission [ISO/IEC 7498-1]
3.1.28 DL-subsystem [ISO/IEC 7498-1]
3.1.29 DL-user-data [ISO/IEC 7498-1]

– 10 – 61158-4-14  IEC:2010
3.1.30 flow control [ISO/IEC 7498-1]
3.1.31 layer-management [ISO/IEC 7498-1]
3.1.32 multiplexing [ISO/IEC 7498-3]
3.1.33 naming-(addressing)-authority [ISO/IEC 7498-3]
3.1.34 naming-(addressing)-domain [ISO/IEC 7498-3]
3.1.35 naming-(addressing)-subdomain [ISO/IEC 7498-3]
3.1.36 (N)-entity [ISO/IEC 7498-1]
DL-entity
Ph-entity
3.1.37 (N)-interface-data-unit
[ISO/IEC 7498-1]
DL-service-data-unit  (N=2)
Ph-interface-data-unit  (N=1)
3.1.38 (N)-layer [ISO/IEC 7498-1]
DL-layer  (N=2)
Ph-layer  (N=1)
3.1.39 (N)-service [ISO/IEC 7498-1]
DL-service  (N=2)
Ph-service  (N=1)
3.1.40 (N)-service-access-point [ISO/IEC 7498-1]
DL-service-access-point  (N=2)
Ph-service-access-point  (N=1)
3.1.41 (N)-service-access-point-address
[ISO/IEC 7498-1]
DL-service-access-point-address  (N=2)
Ph-service-access-point-address  (N=1)
3.1.42 peer-entities [ISO/IEC 7498-1]
3.1.43 Ph-interface-control-information
[ISO/IEC 7498-1]
3.1.44 Ph-interface-data [ISO/IEC 7498-1]
3.1.45 primitive name [ISO/IEC 7498-3]
3.1.46 reassembling [ISO/IEC 7498-1]
3.1.47 recombining
[ISO/IEC 7498-1]
3.1.48 reset [ISO/IEC 7498-1]
3.1.49 responding-DL-address
[ISO/IEC 7498-3]
3.1.50 routing [ISO/IEC 7498-1]
3.1.51 segmenting
[ISO/IEC 7498-1]
3.1.52 sequencing [ISO/IEC 7498-1]
3.1.53 splitting [ISO/IEC 7498-1]
3.1.54 synonymous name [ISO/IEC 7498-3]
3.1.55 systems-management [ISO/IEC 7498-1]

61158-4-14  IEC:2010 – 11 –
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 DL-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 ISO/IEC 8802-3 terms
This standard also makes use of the following terms defined in ISO/IEC 8802-3 as they apply
to the data-link layer:
– 12 – 61158-4-14  IEC:2010
3.3.1 destination address
3.3.2 frame check sequence
3.3.3 length/type
3.3.4 MAC frame
3.3.5 pad
3.3.6 source address
3.4 Common terms and definitions
NOTE Many definitions are common to more than one protocol Type; they are not necessarily used by all protocol
Types.
3.4.1
communication macrocycle
set of basic cycles needed for a configured communication activity in a macro network
segment
3.4.2
communication phase
elapsed fraction of a cycle, measured from some fixed origin
3.4.3
communication scheduling
algorithms and operation for data transfers occurring in a deterministic and repeatable
manner
3.4.4
cyclic
repetitive in a regular manner
3.4.5
data DLPDU
DLPDU that carries a DLSDU from a local DLS-user to a remote DLS-user
3.4.6
destination FB Instance
FB instance that receives the specified parameters
3.4.7
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
3.4.8
DLSAP
distinctive point at which DL-services are provided by a single DL-entity to a single higher-
layer entity.
NOTE This definition, derived from ISO/IEC 7498-1, is repeated here to facilitate understanding of the critical
distinction between DLSAPs and their DL-addresses. (See Figure 1.)

61158-4-14  IEC:2010 – 13 –
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 may have multiple DLSAP-addresses and group DL-addresses associated with a
single DLSAP.
Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses
3.4.9
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 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
3.4.10
(individual) DLSAP-address
DL-address that designates only one DLSAP within the extended link
NOTE A single DL-entity may have multiple DLSAP-addresses associated with a single DLSAP.
3.4.11
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 An extended link may be composed of just a single link.
3.4.12
FCS error
error that occurs when the computed frame check sequence value after reception of all the
octets in a DLPDU does not match the expected residual

– 14 – 61158-4-14  IEC:2010
3.4.13
frame
denigrated synonym for DLPDU
3.4.14
group DL-address
DL-address that potentially designates more than one DLSAP within the extended link. 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
3.4.15
micro segment
part of a network, where special scheduling is implemented.
3.4.16
multipoint connection
connection from one node to many nodes.
NOTE Multipoint connections allows data transfer from a single publisher to be received by many subscriber
nodes.
3.4.17
node
single DL-entity as it appears on one local link
3.4.18
offset
number of octets from a specially designated position
3.4.19
real-time
ability of a system to provide a required result in a bounded time
3.4.20
real-time communication
transfer of data in real-time.
3.4.21
real-time Ethernet (RTE)
ISO/IEC 8802-3-based network that includes real-time communication
NOTE 1 Other communication can be supported, providing the real-time communication is not compromised.
NOTE 2 This definition is dedicated, but not limited, to ISO/IEC 8802-3. It could be applicable to other IEEE 802
specifications, for example IEEE 802.11.
3.4.22
receiving DLS-user
DL-service user that acts as a recipient of DL-user-data
NOTE A DL-service user can be concurrently both a sending and receiving DLS-user.
3.4.23
schedule
temporal arrangement of a number of related operations.
3.4.24
scheduling macrocycle
time interval to implement a specific schedule.

61158-4-14  IEC:2010 – 15 –
3.4.25
sending DLS-user
DL-service user that acts as a source of DL-user-data
3.4.26
time offset
time difference from a specially designated time
3.5 Symbols and abbreviations
ARP
Address resolution protocol
Cnf
Confirmation
CSMA/CD
Carrier sense multiple access with collision detection (protocol)
DHCP
Dynamic host configuration protocol
DL-
(as a prefix) Data-link-
DLCEP
Data-link connection endpoint
DLL
Data-link layer
DLE
Data-link entity
DLM
Data-link-management
DLS
Data-link service
DLSAP
Data-link service access point
DLSDU
DL-service-data-unit
ECSME
Type 14 communication scheduling management entity
EM_
(as a prefix) Type 14 management
FRT
Fast Real-time
Ind
Indication
IANA
Internet Assigned Numbers Authority
IP
Internet protocol
LLC
Logical link control
LMP
Link management protocol
MAC
Medium access control
MAU
Medium attachment unit
PAD
Pad (bits)
PDU
Protocol data unit
Req
Request
Rsp
Response
RTE
Real-time Ethernet
RT-Ethernet
Real-time Ethernet
SAP
Service access point
SDU
Service data unit
SME
System management entity
SNTP
Simple network time protocol
TCP
Transmission control protocol
UDP
User datagram protocol
– 16 – 61158-4-14  IEC:2010
.cnf
Confirm primitive
.ind
Indication primitive
.req
Request primitive
.rsp
Response primitive
4 Overview of the DL-protocol
4.1 General
4.1.1 DLL architecture
According to the basic fieldbus reference model defined in IEC/TR 61158-1, the Type 14 DLL
is modeled in Figure 2 as an integrated Data link layer with UDP(TCP), IP, MAC and LLC
sublayers defined in ISO/IEC 8802-3 and an extension protocol defined in this part of the
IEC 61158 series, where
Regular ISO/IEC 8802-3
Application layer
FRT applications
RT applications
based applications
RFC 768(UDP)/RFC 793 (TCP)
RFC 791 (IP)
Data link layer
DLL extension sublayer
LLC/MAC defined in ISO/IEC 8802-3
Physical layer
ISO/IEC 8802-3 PhL
Figure 2 – Communication model
• the Transfer Control Protocol (TCP) defined in RFC 793 is applied;
• the User Datagram Protocol (UDP) defined in RFC 768 is applied;
• the Internet Propocol (IP) defined in RFC 791 is applied;
• the Logic Link Control (LLC) protocol defined in ISO/IEC 8802-3 is applied;
• the Medium Access Control (MAC) layer protocol defined in ISO/IEC 8802-3 is applied.
Additionally, a DLL extension sublayer is defined as the Type 14 communication scheduling
management entity (ECSME) on ISO/IEC 8802-3 data link protocol to manage the
deterministic communication and regular communication.
This ECSME provides the following functions:
• transparent data transferring between DLE and DLS_User specified in ISO/IEC 8802-3
without modifying the data;
• receiving DLS_User DATA from DLS_User and buffering them;
• transferring DLS_User DATA to DLE in configured order and priority. The DLE will send it
to Ethernet network using the protocols defined in ISO/IEC 8802-3;
• transferring decoded DLPDU from DLE to DLS_User.
ECSME supports two ways of communication scheduling:
• free competitive communication scheduling based on the CSMA/CD;
• deterministic communication based on the time-sharing scheduling policy defined later.

61158-4-14  IEC:2010 – 17 –
When the former scheduling is used, ECSME shall directly transfer the data between DLE and
DLS_User without any buffering or handling.
When the latter k) is used, the ECSME in each Type 14 device shall transfer DLS_User DATA
to DLE according to the pre-configured timing order and priority, the DLE shall process the
data and send it to PhL, so that the collision is avoided.
4.1.2 Type 14 communication scheduling management entity (ECSME)
ECSME is the extension based on LLC defined in ISO/IEC 8802-3. It transfers data between
DLS_User and LLC without any changing.
ECSME does not alter the services provided by DLL to DLS_User defined in ISO/IEC 8802-3
as well as the interface between PhL and MAC. It only provides the transmission management
of the DLS_User data.
4.1.3 Transaction between DLL and PhL
The transactions between DLL and PhL defined in ISO/IEC 8802-3 are applied without any
changes.
4.1.4 Time synchronization
The time in all Type 14 devices shall be synchronized for the purpose of communication
scheduling (see IEC 61158-5-14).
4.2 Services provided by the DL
4.2.1 Overview
The DLL provides connectionless data transfer services and connection-mode data transfer
services defined in ISO/IEC 8802-3, RFC 791, RFC 768 and RFC 793 protocols.
4.2.2 Priority
Six levels of priority for packet transmission are defined in this specification, namely 0, 1, 2, 3,
4, 5. These are associated with the services defined in IEC 61158-5-14. The highest priority,
that is 0, is used for the cyclic sending of DLSDUs. The execution timing for this fieldbus
scheduled service shall be accurate and repeatable to less than 1 ms for RT applications.
Services with the highest priority are used with UDP/IP protocols. And for FRT applications,
the execution timing for this fieldbus scheduled service shall be accurate and repeatable to
less than 1 us for RT application. Services with the highest priority are used with DLL
protocols directly.
The low priorities provide for sending of DLSDUs only on an as-available basis. Data on these
priorities are sent only when all other higher data priorities have been sent and a sending
opportunity is available. For FRT applications, only one device can send the Nonperiodicdata
in a communication macrocycle. It is recommended that the device which gets opportunity to
send the Nonperiodicdata should send all its Nonperiodicdatas unless non-periodic packet
transferring phase is not enough.
4.2.3 Ethernet type identifier
This specification adopts a registered value of 0x88CB assigned by IANA for LENGTH/TYPE
field in Ethernet frame to identify a Type 14 packet (see Figure 3).

– 18 – 61158-4-14  IEC:2010
802.3 MAC 802.2 SNAP
802.2 LLC
DSAP SSAP cntl Org
Destination Address Source Address Length Type DATA FCS
AA AA 03 code
6 6 2 1 1 1 3 2 38 ~ 1492 4
Type
(UDP/IP +) Type 14 DATA
88CB
2 38 ~ 1492
46 ~ 1500 Octets
Ethernet Encapsulation
Destination Address Source Address Type FCS
DATA
6 6 2 46 ~ 1500 4
Type
(UDP/IP +) Type 14 DATA FCS
88CB
2 46 ~ 1500 4
Figure 3 – Type 14 packet identifier
4.2.4 Time synchronization
The time in all Type 14 devices shall be synchronized for the purpose of communication
scheduling.
4.3 Structure of deterministic communication scheduling
Within a Type 14 micro-segment, the communication procedure is repeated. The time to
complete a communication procedure is called communication macrocycle and marked as T.
Each communication macrocycle (T) is divided into two phases, periodic packet transferring
phase (Tp) and non-periodic packet transferring phase (Tn) (see Figure 4).

Communication Macrocycle T
Periodic packet transfer phase Tp Nonperiodic packet transfer phase Tn
D1
D2
D3
D4
D5
D6
t
Periodic packet
NonPeriodDataAnnunciation packet
Aperiodic packet EndofNonPeriodDataSending annunciation packet

Figure 4 – Time-sharing communication scheduling

61158-4-14  IEC:2010 – 19 –
In the periodic packet transferring phase (Tp), the ECSME of each Type 14 device delivers
periodic DLS_User data to local DLE in a configured order. Local DLE will packet and send
the data on the network after it receives them.
Periodic DLS_User data contain the data relevant to process parameters, such as
measurement and control data which need to be transmitted periodically in the control loop, or
the input/output data which need to be updated cyclically between function blocks. Periodic
DLS_User data has the highest priority to be sent.
In non-periodic packet transferring phase (Tn), the ECSME of each Type 14 device delivers
non-periodic DLS_User data to local DLE according to their priority and the local IP address
or MAC address. The Local DLE will packetize and send the data on the network after it
receives them.
Non-periodic DLS_User data contain the data which do not need to send out in every
macrocycle. That is, non-periodic DLS_User data are not produced cyclically. In Type 14
systems, non-periodic DLS_User data are the primitives of program upload/download,
variable read/write, event notification, trend report and RARP, HTTP, FTP, TFTP, ICMP,
IGMP application data, etc. In other cases, the primitives of SNTP and DHCP services are
regarded as non-periodic DLS_User data.
Non-periodic data are sent out according to their priority, local IP address or MAC address in
time-available way. That is,
• if time is available, the non-periodic packet with high priority is sent first;
• if two or more non-periodic packets in local device have identical priority, the one
produced first is sent first;
• if two or more non-periodic packets are located in different devices, those located in the
devices with smaller IP address are sent out first.
For FRT applications:
• DL-management packets shall not be send;
• DL-management tag is an optional segment in the periodic packets to indicate the priority
of the next non-periodic packet ;
• if there are no non-periodic packets to be sent or managed at any time, DL-management
can be omitted;
• during a single ma
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