IEC 62056-4-7:2015

IEC 62056-4-7 ®
Edition 1.0 2015-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electricity metering data exchange – The DLMS/COSEM suite –
Part 4-7: DLMS/COSEM transport layer for IP networks

Échange des données de comptage de l'électricité – La suite DLMS/COSEM –
Partie 4-7: Couche transport DLMS/COSEM pour réseaux IP

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IEC 62056-4-7 ®
Edition 1.0 2015-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electricity metering data exchange – The DLMS/COSEM suite –

Part 4-7: DLMS/COSEM transport layer for IP networks

Échange des données de comptage de l'électricité – La suite DLMS/COSEM –

Partie 4-7: Couche transport DLMS/COSEM pour réseaux IP

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220; 35.110; 91.140.50 ISBN 978-2-8322-2609-4

– 2 – IEC 62056-4-7:2015  IEC 2015
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviations . 8
3.1 Terms and definitions . 8
3.2 Abbreviations . 8
4 Overview . 9
5 The DLMS/COSEM connection-less, UDP-based transport layer . 10
5.1 General . 10
5.2 Service specification for the DLMS/COSEM UDP-based transport layer . 11
5.2.1 General . 11
5.2.2 The UDP-DATA service . 12
5.3 Protocol specification for the DLMS/COSEM UDP-based transport layer . 14
5.3.1 General . 14
5.3.2 The wrapper protocol data unit (WPDU) . 14
5.3.3 The DLMS/COSEM UDP-based transport layer protocol data unit . 15
5.3.4 Reserved wrapper port numbers (wPorts) . 16
5.3.5 Protocol state machine . 16
6 The DLMS/COSEM connection-oriented, TCP-based transport layer . 16
6.1 General . 16
6.2 Service specification for the DLMS/COSEM TCP-based transport layer . 17
6.2.1 General . 17
6.2.2 The TCP-CONNECT service . 18
6.2.3 The TCP-DISCONNECT service . 21
6.2.4 The TCP-ABORT service . 23
6.2.5 The TCP-DATA service . 24
6.3 Protocol specification for the DLMS/COSEM TCP-based transport layer . 26
6.3.1 General . 26
6.3.2 The wrapper protocol data unit (WPDU) . 26
6.3.3 The DLMS/COSEM TCP-based transport layer protocol data unit . 27
6.3.4 Reserved wrapper port numbers . 27
6.3.5 Definition of the procedures . 27
Annex A (informative) Converting OSI-style TL services to and from RFC-style TCP
function calls. 32
A.1 Transport layer and TCP connection establishment . 32
A.2 Closing a transport layer and a TCP connection . 33
A.3 TCP connection abort . 34
A.4 Data transfer using the TCP-DATA service . 35
INDEX . 37
Bibliography . 38

Figure 1 – DLMS/COSEM as a standard Internet application protocol . 9
Figure 2 – Transport layers of the DLMS/COSEM_on_IP profile . 10
Figure 3 – Services of the DLMS/COSEM connection-less, UDP-based transport layer . 12

Figure 4 – The wrapper protocol data unit (WPDU) . 15
Figure 5 – The DLMS/COSEM connection-less, UDP-based transport layer PDU (UDP-
PDU) . 15
Figure 6 – Services of the DLMS/COSEM connection-oriented,TCP-based transport
layer . 18
Figure 7 – The TCP packet format . 27
Figure 8 – TCP connection establishment . 28
Figure 9 – TCP disconnection . 29
Figure 10 – Data transfer using the DLMS/COSEM TCP-based transport layer . 30
Figure 11 – High-level state transition diagram for the wrapper sublayer . 31
Figure A.1 – TCP connection state diagram . 32
Figure A.2 – MSC and state transitions for establishing a transport layer and TCP
connection . 33
Figure A.3 – MSC and state transitions for closing a transport layer and TCP
connection . 34
Figure A.4 – Polling the TCP sublayer for TCP abort indication . 34
Figure A.5 – Sending an APDU in three TCP packets . 35
Figure A.6 – Receiving the message in several packets . 36

Table 1 – Reserved wrapper port numbers in the UDP-based DLMS/COSEM TL . 16

– 4 – IEC 62056-4-7:2015  IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICITY METERING DATA EXCHANGE –
THE DLMS/COSEM SUITE –
Part 4-7: DLMS/COSEM transport layer for IP networks

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 Ava
...