SIST EN 61334-4-1:1997

SLOVENSKI STANDARD
SIST EN 61334-4-1:1997
01-avgust-1997
Distribution automation using distribution line carrier systems - Part 4: Data
communication protocols - Section 1: Reference model of the communication
system (IEC 1334-4-1:1996)
Distribution automation using distribution line carrier systems -- Part 4: Data
communication protocols -- Section 1: Reference model of the communication system
Verteilungsautomatisierung mit Hilfe von Trägersystemen auf Verteilungsleitungen -- Teil
4: Datenkommunikationsprotokolle -- Hauptabschnitt 1: Referenzmodell für das
Kommunikationsystem
Automatisation de la distribution à l'aide de systèmes de communication à courants
porteurs -- Partie 4: Protocoles de communication de données -- Section 1: Modèle de
référence du système de communication
Ta slovenski standard je istoveten z: EN 61334-4-1:1996
ICS:
29.240.20 Daljnovodi Power transmission and
distribution lines
33.040.40 Podatkovna komunikacijska Data communication
omrežja networks
SIST EN 61334-4-1:1997 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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NORME CEI
INTERNATIONALE IEC
1334-4-1
INTERNATIONAL
Première édition
STANDARD
First edition
1996-07
Automatisation de la distribution à l'aide
de systèmes de communication à
courants porteurs -
Partie 4:
Protocoles de communication de données -
Section 1: Modèle de référence du système
de communication
Distribution automation using
distribution line carrier systems -
Part 4:
Data communication protocols -
Section 1: Reference model of the
communication system
Numéro de référence
IEC
Reference number
•
CEI/IEC 1334-4-1: 1996

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— 3 —
1334-4-1 ©IEC: 1996
CONTENTS
Page
FOREWORD 7
INTRODUCTION 9
Clause
11
1 Scope
11
2 Nonnative references
13
3 Description of the reference model
13
3.1 Introduction
13
3.2 Basic principles of the OSI model
13
3.2.1 Layered architecture
15 3.2.2 Services and protocols
17
3.3 Reference model
17 3.3.1 Minimal three-layer architecture
21 3.3.2 Basic transmission principles
3.3.3 Physical layer 21
3.3.4 Data link layer 23
3.3.5 MAC sublayer 23
3.3.6 LLC sublayer 23
25
3.3.7 Optional intermediate layers
25
3.3.8 Application layer
27
3.3.9 Network management
3.4 Systems management 29
29
4 Naming and addressing in DCP
4.1 General overview 29
4.1.1 Naming 29
31
4.1.2 Addressing
33
4.1.3 Registration authority for naming and addressing
33
4.1.4 Directories
33 4.2 Global description
35
4.3 MAC addresses
35
4.3.1 MAC address format
35
4.3.2 Predefined MAC addresses
37
4.4 LLC addresses
4.4.1 LLC address format 37

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1334-4-1 ©IEC: 1996 —5 —
37
4.4.2 DL selector types
39
4.4.3 LLC predefined selector
39
4.5 Application process titles
39
4.5.1 Titles overview
41
4.5.2 Predefined titles
43
Annex A — Bibliography

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– 7 –
1334-4-1 © IEC: 1996
INTERNATIONAL ELECTROTECHNICAL COMMISSION
DISTRIBUTION AUTOMATION USING
DISTRIBUTION LINE CARRIER SYSTEMS —
Part 4 : Data communication protocols —
Section 1: Reference model of the communication system
FOREWORD
The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising all national
1)
electrotechnical committees (IEC National Committees). The object of the IEC is to promote international cooperation on all
questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, the IEC
publishes International Standards. 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. The IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
The formal decisions or agreements of the IEC on technical matters express as nearly as possible an international consensus of
2)
opinion on the relevant subjects since each technical committee has representation from all interested National Committees.
The documents produced have the form of recommendations for international use and are published in the form of standards,
3)
technical reports or guides and they are accepted by the National Committees in that sense.
In order to promote international unification, IEC National Committees undertake to apply IEC International Standards
4)
transparently to the maximum extent possible in their national and regional standards. Any divergence between the IEC Standard
and the corresponding national or regional standard shall be clearly indicated in the latter.
The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to
5)
be in conformity with one of its standards.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights.
6)
IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 1334-4-1 has been prepared by IEC technical committee 57: Power system control
and associated communications.
The text of this standard is based on the following documents:
Report on voting
FDIS
57/280/RVD
57/260/FDIS
Full information on the voting for the approval of this standard can be found in the report on voting indicated in
the above table.
Annex A is for information only.

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1334-4-1 ©IEC: 1996 – 9 –
INTRODUCTION
The documents specifying communication through power line carrier systems aim at drawing up a
comprehensive specification according to the structure of the open system interconnection model (OSI
from ISO).
This reference model provides a basic description. Details of the specifications are given in the
rt 4.
other sections of pa
This document describes the communication system based on a three-layer model. Future
extensions to more layers are possible.

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1334-4-1 © IEC: 1996 – 11 –
DISTRIBUTION AUTOMATION USING
DISTRIBUTION LINE CARRIER SYSTEMS —
Part 4 : Data communication protocols —
Section 1: Reference model of the communication system
1 Scope
The scope of application of the specifications of the sections of part 4 is the communication through
the so-called distribution line carrier technology (DLC) on both low and medium voltage distribution
network. The application range based on telecommunication processes is wide and cannot be described
exhaustively in this section; application examples are: control and monitoring of the distribution network,
order broadcast, control of user interfaces, public lighting, traffic lights supervision, automatic meter
reading, etc.
Extensions to other communication media are also allowed.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this section of IEC 1334-4. At the time of publication, the editions indicated were
rties to agreements based on this section of
valid. All normative documents are subject to revision, and pa
IEC 1334-4 are encouraged to investigate the possibility of applying the most recent editions of the
normative documents listed below. Members of IEC and ISO maintain registers of currently valid
International Standards.
IEC/FDIS 1334-4-32: Distribution automation using distribution line carrier systems –
Part 4: Data communication protocols – Section 32: Data link layer – Logical link control*
IEC 1334-4-41: 1996, Distribution automation using distribution line carrier systems – Part 4:
Data communication protocols – Section 41: Application protocols – Distribution line message
specification
IEC/FDIS 1334-4-42: Distribution automation using distribution line carrier systems –
Part 4: Data communication protocols – Section 42: Application protocols – Application layer**
ISO/IEC 7498-3: 1989, Information processing systems - Open Systems Interconnection - Basic
Reference Model - Part 3 : Naming and addressing
ISO/TEC 8802-2: 1994, Information technology – Telecommunications and information exchange
between systems – Local and metropolitan area networks – Specific requirements – Part 2: Logical link
control
*
At present at the stage of Final Draft International Standard (57/266/FDIS).
** At present at the stage of Final Draft International Standard (57/265/FDIS).

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– 13 –
1334-4-1 © IEC: 1996
3 Description of the reference model
3.1 Introduction
The specification of a communication system, such as an industrial local network or a set of
interconnected subnetworks serves the following purpose: opening of the corresponding equipment to
distributed applications, giving official recognition to, and perpetuating, ongoing developments,
implementing tools and structures for conformance testing in order to promote the interworking capability.
transmission network fully justifies such a specification since this
The distribution line carrier
communication system can be used for a large number of devices with various functions (station control
transformer station concentrators, portable input stations,
unit, remote controlled feeder switch, meters,
lighting sources, automatic traffic lights at crossroads) which are manufactured by several competing
suppliers.
According to the rules in the field of telecommunication this specification should be comprehensive
and unambiguous and should comply with the economic requirements of final applications.
3.2 Basic principles of the OSI model
3.2.1 Layered architecture
The purpose of the OSI standardisation is the development of standardised telecommunication
networks capable of supporting a wide range of heterogeneous equipment in order to form an "open
system". So that this heterogeneity may be possible, the OSI standards are restricted to the specification of
the functions to be performed by each open system and of the protocols which are to be implemented
between these systems. They avoid prescribing a particular mode for the achievement of the corresponding
functions. Thus, the OSI standards specify the behavior of open systems as a whole in their exchanges with
other open systems and not their internal operation. The conformity of a real system with the given
specifications is based on the external view of its behavior during its exchanges with other systems.
Among the different models for the organisation of activities, the OSI has chosen the layered model
and features seven layers: physical layer, data link layer, network layer, transport layer, session layer,
presentation layer and application layer.

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1334-4-1 © IEC: 1996 – 15 –
3.2.2 Services and protocols
The OSI model defines elementary concepts in order to describe the operation of each layer through
its relationships with adjacent layers.
(N+1)-layer
(N)-Services: services requested
from a (N)-layer by a (N+1)-layer
8
(N)-layer
Figure 1 – OSI service definition
Within open systems, the functions of the (N+1)-layer are carried out through (N+1)-entities. The
interface between (N+1)-entities and entities with a lower index is achieved in the form of an interaction
rvice, at right angles with access points called (N)-SAP. The cooperation between
service called (N) se
out the functions of the (N+1)-layer is governed by the (N+1)-protocol.
(N+1)-entities in order to car ry
Figure 2 – OSI data unit correspondence

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– 17 –
1334-4-1 0 IEC: 1996
With regard to the information exchange, the (N-1) service performs the transfer of (N-1) service-
data-units ((N-1) SDUs) between (N-1)-SAPs. Thus, the (N)-entities can exchange (N)-protocol-data-units
((N)-PDUs) by putting them in (N-1)-SDUs. Each (N)-PDU can include the (N)-protocol-control-
information ((N)-PCI) and the (N)-user-data.
3.3 Reference model
Although OSI describes seven layers for a full implementation, it is possible to reduce the
implementation complexity for simple systems to a three layer, or collapsed, architecture. The minimally
retained layers are: physical layer, data link and application layer. Based on this collapsed architecture it is
possible to build the communication systems used for low voltage DLC applications.
the medium
In order to leave the door open for future, more complex, systems, especially on
voltage networks, the interface between the data link and the application layer is specified generally
enough to later include other layers, for example network or transport layers, should the system
functionally call for it (see 3.3.7).
3.3.1 Minimal three-layer architecture
The method used for the drawing up of the Data Communication Protocol (DCP) specification
consisted in defining the state-of-the-art existing standards and designing the collection of service entities
as a whole.
Whenever possible, already available and well-tried specification elements have been re-used (IEC,
ISO, IEEE standards).
The global approach of the different service entities which make up the protocol layers ensures the
balance and robustness of the whole without neglecting any part of the specification. Thus, the network
management has been taken into account in the conception of each layer.
The protocol selection is determined by the following issues:
search for high effectiveness with low baud rates and high propagation times;
-
- low requirement with regard to interconnection and meshed networks;
- search for optimal channel availability for the concentrator station;
- high level of automation for administration functions;
- the difficult nature of the distribution network as a communications channel;
- the whole combined with a low-cost solution.

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1334-4-1 © IEC: 1996 – 19 –
These considerations led to a specification which includes three protocol layers. Such an
architecture is known as a "collapsed architecture". It offers sufficient addressing and service capabilities
for power line carrier applications.
^
A.P. 2
A.P. 1
SMAP
MIB
pplicatioh Layer I
DL-Service
L-SAP
N‘,%,`^^\^^^^^^`^`\\^^^^ ^
^^^ `
toy
°
\^^^^^^^^^^^^\\\\\\\\\\^ _
_.^^`\\\ \\\\\\
LL'
sole
Data Link Layer
P-Services
\ \ N
—► Physical Layer
Medium
Figure 3 – Reference model
The main advantage of this three-layer architecture rests in its effectiveness in terms of its useful
throughput and in the low degree of complexity of the operations to be carried out on the received data.
The three layers of this architecture are the physical layer, the data link layer and the application
layer. The first two layers describe symmetrical behaviours for communicating entities. This symmetry is
disrupted by the application layer which adopts the user-server model recommended among others in the
manufacturing message specification MMS.

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1334-4-1 © IEC: 1996 –21
-3.3.2 Basic transmission principles
The design requirement or characteristics of the communication protocol are:
- independence from physical network topology;
- independence from the modulation scheme;
- medium access strategy (time sharing) is application dependant.
At a given time, the network may be organised around a particular system called the "Initiator". All
other units are then acting as servers; they may access the media only when specifically requested by the
Initiator. The application layer asks for access when it is requested by the application of the Initiator. The
medium access strategy is located at the application process of the Initiator.
In order to preserve flexibility and openness to the communication network, the assignment of the
role of the Initiator may change.
Under very bad transmission conditions (high noise level and great attenuation), it may become
necessary to provide a relaying mechanism to ensure effective data communication across the whole
network. The relaying mechanism is defined in the MAC sublayer.
3.3.3 Physical layer
The physical layer is described in future IEC 1334-4-2 * .
is the power distribution network. However,
NOTE – The communications medium referred to in this section
alternative communications media are also within the scope of data communications protocols.
The physical layer has a double purpose. First of all, it provides the interface between the
transmission medium, that is the distribution network. It is then used for
equipment and the physical
carrying out the transfer from the source to the destination via the transmitted binary elements.
For this purpose, the specification defines the set of minimal properties for the physical interface,
which complies with the requirements of the power line carrier communication and describes the binary
elements code and the synchronisation schema for the transmitted signals.
* At present under consideration. See annex B of IEC 1334-1-1 for details of future publications in the IEC 1334 series.

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– 23 –
1334-4-1 © IEC: 1996
The main characteristics of the physical layer are :
- medium : power distribution network;
- narrow and spread spectrum modulation techniques;
- can be implemented at low cost.
The DCP physical layer does not describe a particular modulation method nor a particular bit-rate.
It describes characteristics of a real physical layer which are mandatory to allow the working of the
protocol. These characteristics are then mainly broad and general.
3.3.4 Data link layer
As usual, the data link layer includes two sublayers MAC and LLC. They control respectively the
access to the medium (MAC, Medium Access Control) and the logical links (LLC, Logical Link Control).
, IEC/FDIS 1334-4-32 and future IEC
*
The data link layer is described in future IEC 1334-4-31
1334-4-33 (see bibliography). Section 31 describes the Medium Access Control sublayer and section 32
describes the Logical Link Control sublayer.
3.3.5 MAC sublayer
The MAC sublayer is intended mainly to handle the access to the physical medium and the
addressing of physical equipment. This is the only medium access constraint defined in DCP. At times
when the network is organised around an Initiator, the decision to access the medium is made by the
Initiator, directly for its own MAC sublayer, or indirectly for other MAC sublayers that are requested to
transmit a response to a question asked previously by the Initiator.
The MAC sublayer provides for a high level of data integrity (Class I2) with a protocol independent
of the selected physical modulation.
3.3.6 LLC sublayer
The LLC sublayer is derived from ISO/IEC 8802-2.
It performs
...