IEC 62056-46:2002

INTERNATIONAL IEC
STANDARD
62056-46
First edition
2002-02
Electricity metering –
Data exchange for meter reading,
tariff and load control –
Part 46:
Data link layer using HDLC protocol
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INTERNATIONAL IEC
STANDARD
62056-46
First edition
2002-02
Electricity metering –
Data exchange for meter reading,
tariff and load control –
Part 46:
Data link layer using UDLC protocol
 IEC 2002  Copyright - all rights reserved
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mechanical, including photocopying and microfilm, without permission in writing from the publisher.
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International Electrotechnical Commission
For price, see current catalogue

– 2 – 62056-46  IEC:2002(E)
CONTENTS
FOREWORD .4
1 Scope.6
2 Normative references .6
3 Terms, definitions and abbreviations .7
4 Overview .8
4.1 The LLC sub-layer.8
4.2 The MAC sub-layer.8
4.3 Specification method .8
5 The LLC sub-layer .9
5.1 The role of the LLC sub-layer .9
5.2 Service specification for the LLC sub-layer.9
5.2.1 Setting up the Data Link Connection.10
5.2.2 Disconnecting the Data Link Connection.13
5.2.3 Data communication .16
5.3 Protocol specification for the LLC sub-layer.20
5.3.1 Overview .20
5.3.2 LLC protocol data unit (LPDU) structure .20
5.3.3 State transition tables for the LLC sub-layer .21
6 The MAC sub-layer.22
6.1 HDLC selections.22
6.2 Service specification for the MAC sub-layer.22
6.2.1 Setting up the MAC connection.22
6.2.2 Disconnecting the MAC connection.26
6.2.3 Data communication .30
6.3 Physical layer services used by the MAC sub-layer .32
6.3.1 Overview .32
6.3.2 Setting up a physical link .33
6.3.3 Disconnecting the physical link .33
6.3.4 Data communication .33
6.4 Protocol specification for the MAC sub-layer .33
6.4.1 The MAC PDU and the HDLC frame .33
6.4.2 MAC addressing .35
6.4.3 Command and response frames .39
6.4.4 Elements of the procedures .42
6.4.5 State transition diagram for the server MAC sub-layer .57
Annex A (informative) FCS calculation.59
Annex B (informative) Data model and protocol .62
Annex C (informative) Data link layer management services .63

62056-46  IEC:2002(E) – 3 –
Figure 1 – Data Link (LLC) services for setting up the Data Link Connection .10
Figure 2 – Data Link (LLC) services for disconnecting the Data Link Connection .13
Figure 3 – Data link layer data communication services .17
Figure 4 – The ISO/IEC 8802-2 LLC protocol data unit format.20
Figure 5 – The used LLC protocol data unit format.20
Figure 6 – MAC sub-layer services for setting up the MAC (DL) connection at the client
and server sides .23
Figure 7 – MAC sub-layer services for disconnecting the MAC (DL) connection at the
client and server sides .26
Figure 8 – MAC sub-layer data communication services .30
Figure 9 – Physical layer services used by the MAC sub-layer.33
Figure 10 – MAC sub-layer frame format (HDLC frame format type 3).34
Figure 11 – Multiple frames.34
Figure 12 – The frame format field .34
Figure 13 – MSC for long MSDU transfer in a transparent manner .51
Figure 14 – Example configuration to illustrate broadcasting.52
Figure 15 – Sending out a pending UI frame with a .response data.53
Figure 16 – Sending out a pending UI frame with a response to a RR frame .54
Figure 17 – Sending out a pending UI frame on receipt of an empty UI frame .54
Figure 18 – State transition diagram for the server MAC sub-layer.58
Figure B.1 – The three-step approach of COSEM .62
Figure C.1 – Layer management services .63
Table 1 – State transition table of the client side LLC sub-layer .21
Table 2 – State transition table of the server side LLC sub-layer.21
Table 3 – Table of reserved client addresses .37
Table 4 – Table of reserved server addresses.37
Table 5 – Handling inopportune address lengths.39
Table 6 – Command and response frames .39
Table 7 – Control field format.40
Table 8 – Example for parameter negotiation values with the SNRM/UA frames .47
Table 9 – Summary of MAC Addresses for the example.52
Table 10 – Broadcast UI frame handling .52

– 4 – 62056-46  IEC:2002(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ELECTRICITY METERING – DATA EXCHANGE
FOR METER READING, TARIFF AND LOAD CONTROL –
Part 46: Data link layer using HDLC protocol
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote inter-
national co-operation 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 Standardiza-
tion (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an interna-
tional consensus of opinion on the relevant subjects since each technical committee has representation from all
interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National Com-
mittees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any diver-
gence between the IEC Standard and the corresponding national or regional standard shall be clearly indicated
in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
The International Electrotechnical Commission (IEC) draws attention to the fact that it is claimed that compliance
with this International Standard may involve the use of a maintenance service concerning the stack of protocols on
which the present standard IEC 62056-46 is based.
The IEC takes no position concerning the evidence, validity and scope of this maintenance service.
The provider of the maintenance service has assured the IEC that he is willing to provide services under reason-
able and non-discriminatory terms and conditions for applicants throughout the world. In this respect, the statement
of the provider of the maintenance service is registered with the IEC. Information may be obtained from:
DLMS User Association
Geneva / Switzerland
www.dlms.ch
International Standard IEC 62056-46 has been prepared by IEC technical committee 13:
Equipment for electrical energy measurement and load control.
The text of this standard is based on the following documents:
FDIS Report on voting
13/1267/FDIS 13/1273/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 the ISO/IEC Directives, Part 3.
________
Device Language Message Specification.

62056-46  IEC:2002(E) – 5 –
Annexes A, B and C are for information only.
The committee has decided that the contents of this publication will remain unchanged until
2006. 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.

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ELECTRICITY METERING – DATA ECHANGE
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