IEC 62056-8-6:2017

IEC 62056-8-6 ®
Edition 1.0 2017-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electricity metering data exchange – The DLMS/COSEM suite –
Part 8-6: High speed PLC ISO/IEC 12139-1 profile for neighbourhood networks

Échange des données de comptage de l'électricité – La suite DLMS/COSEM –
Partie 8-6: Profil CPL ISO/IEC 12139-1 à grande vitesse pour les réseaux de
voisinage
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IEC 62056-8-6 ®
Edition 1.0 2017-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electricity metering data exchange – The DLMS/COSEM suite –

Part 8-6: High speed PLC ISO/IEC 12139-1 profile for neighbourhood networks

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

Partie 8-6: Profil CPL ISO/IEC 12139-1 à grande vitesse pour les réseaux de

voisinage
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220; 35.110; 91.140.50 ISBN 978-2-8322-4150-9

– 2 – IEC 62056-8-6:2017  IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 8
4 Targeted communication environments . 9
5 Use of the communication layers for this profile . 10
5.1 Information related to the use of the standard specifying the lower layers . 10
5.2 Structure of the communication profile . 10
5.3 Lower protocol layers and their use. 11
5.3.1 Overview . 11
5.3.2 Physical layer . 11
5.3.3 MAC layer. 11
5.4 Service mapping and adaptation layers . 11
5.4.1 Overview . 11
5.4.2 CPAS . 12
5.4.3 IP SSAS . 12
5.4.4 HDLC SSAS . 16
5.5 Registration and connection management . 19
6 Identification and addressing schemes . 19
7 Specific considerations for the application layer services . 20
7.1 Overview. 20
7.2 Application Association establishment and release: ACSE services . 20
7.3 xDLMS services . 20
7.4 Security mechanisms . 21
7.5 Transferring long application messages . 21
7.6 Media access, bandwidth and timing considerations . 21
7.7 Other considerations . 21
8 Communication configuration and management . 21
9 The COSEM application process . 21
10 Additional considerations for the use of this profile . 21
Annex A (informative) Examples . 22
A.1 IP-based communication examples . 22
A.2 HDLC-based communication examples . 25
A.2.1 Example 1: Data link layer connection establishment (SNRM-UA
exchange). 25
A.2.2 Example 2: Establishment of an AA (AARQ – AARE exchange) . 26
A.2.3 Example 3: Data communication (Get-request) . 28
A.2.4 Example 4: Disconnection example with Releasing (DISC) . 30
Annex B (normative) COSEM ICs for data exchange using HS-PLC ISO/IEC 12139-1
neighbourhood networks . 32
B.1 General . 32
B.2 Interface classes for setting up and managing DLMS/COSEM HS-PLC
ISO/IEC 12139-1 networks . 32

B.2.1 Overview . 32
B.2.2 HS-PLC ISO/IEC 12139-1 MAC setup (class_id = 140, version = 0) . 32
B.2.3 HS-PLC ISO/IEC 12139-1 CPAS setup (class_id = 141, version = 0) . 33
B.2.4 HS-PLC ISO/IEC 12139-1 IP SSAS setup (class_id = 142, version = 0) . 34
B.2.5 HS-PLC ISO/IEC 12139-1 HDLC SSAS setup (class_id = 143, version =
0). 35
B.3 Relation to OBIS . 35
B.3.1 Use of value group C . 35
B.3.2 Objects for data exchange using DLMS/COSEM HS-PLC ISO/IEC
12139-1 networks . 36
Index . 37

Figure 1 – Entities and interfaces of a smart metering system using the terminology of
IEC 62056-1-0 . 9
Figure 2 – DLMS/COSEM High Speed PLC profile . 10
Figure 3 – Adaptation layer architecture . 11
Figure 4 – CPAS frame structure . 12
Figure 5 – IP SSAS control packet . 13
Figure 6 – IP SSAS data packet . 13
Figure 7 – HDLC SSAS Frame . 16
Figure 8 – Message configuration for response to HDLC addresses request . 17

Table 1 – IP SSAS control packet format Inconsistencies! IP_Len . 13
Table 2 – IP SSAS data packet format . 14
Table 3 – Values for IP_Header_Comp_Type . 15
Table 4 – Valid range of the Transmission_status value . 16
Table 5 – HDLC SSAS Frame format . 17
Table 6 – Usage of CMD and STA fields . 17
Table 7 – Client and Server SAPs for the IP based communication . 20
Table 8 – Client and Server SAPs for the HDLC based communication . 20
Table B.1 – Use of value group C for abstract objects in the COSEM context . 36

– 4 – IEC 62056-8-6:2017  IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICITY METERING DATA EXCHANGE –
THE DLMS/COSEM SUITE –
Part 8-6: High speed PLC ISO/IEC 12139-1
profile for neighbourhood 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
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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.
International Standard IEC 62056-8-6 has been prepared by IEC technical committee 13:
Electrical energy measurement and control.
The text of this standard is based on the following documents:
FDIS Report on voting
13/1730/FDIS 13/1741/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 2.

A list of all parts in the IEC 62056 series, published under the general title Electricity metering
data exchange – The DLMS/COSEM suite, can be found on the IEC website.
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.
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 62056-8-6:2017  IEC 2017
INTRODUCTION
As defined in IEC 62056-1-0, the IEC 62056 DLMS/COSEM suite provides specific
communication profile standards for communication media relevant for smart metering.
Such communication profile standards specify how the COSEM data model and the
DLMS/COSEM application layer can be used on the lower, communication media-specific
protocol layers.
Communication profile standards refer to communication standards that are part of the
IEC 62056 DLMS/COSEM suite or to any other open communication standard.
This document specifies the DLMS/COSEM profile for High Speed PLC (HS-PLC)
technologies according to ISO/IEC 12139-1 for neighbourhood networks. The technology is
based on Discrete Multi-Tone (DMT) modulation. It may be used in low voltage or on medium
voltage distribution networks. The PHY rate of High Speed PLC is typically 24 Mbps, however
the data throughput varies according to many aspects of low voltage or medium voltage power
lines. Although High Speed PLC can be used both on low voltage and medium voltage
networks, in this document HS-PLC on low voltage network is only considered.
When implementing advanced services based on DLMS/COSEM profiles such as complex
tariff programs, data security measures, two-way consumption data exchange for demand
response and so forth, the neighbourhood network may become a bottleneck. The HS-PLC
technology minimizes such bottlenecks due to the high data rates available. Moreover, the
HS-PLC technology can accommodate increased amounts of data thus it can additionally
support other applications such as Internet of Things (IoT).
Using the high speed PLC technology specified in ISO/IEC 12139-1 may be subject to
national regulations. However, this aspect is outside the Scope of this document.

ELECTRICITY METERING DATA EXCHANGE –
THE DLMS/COSEM SUITE –
Part 8-6: High speed PLC ISO/IEC 12139-1
profile for neighbourhood networks

1 Scope
This part of IEC 62056 specifies the DLMS/COSEM communication profile for ISO/IEC
12139-1 High speed PLC (HS-PLC) neighbourhood networks.
It uses the standard ISO/IEC 12139-1 established by ISO/IEC JTC1 SC06.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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 62056-1-0:2014, Electricity metering data exchange – The DLMS/COSEM suite –
Part 1-0: Smart metering standardisation framework
IEC TS 62056-1-1:2016, Electricity metering data exchange – The DLMS/COSEM suite –
Part 1-1: Template for DLMS/COSEM communication profile standards
IEC 62056-46, Electricity metering – Data exchange for meter reading, tariff and load control
– Part 46: Data link layer using HDLC protocol
IEC 62056-4-7, Electricity metering data exchange – The DLMS/COSEM suite – Part 4-7:
DLMS/COSEM transport layer for IP networks
IEC 62056-5-3, Electricity metering data exchange – The DLMS/COSEM suite – Part 5-3:
DLMS/COSEM application layer
IEC 62056-6-1, Electricity metering data exchange – The DLMS/COSEM suite – Part 6-1:
Object Identification System (OBIS)
IEC 62056-6-2:2016, Electricity metering data exchange – The DLMS/COSEM suite –
Part 6-2: COSEM interface classes
IEC 62056-7-6, Electricity metering data exchange – The DLMS/COSEM suite – Part 7-6:
The 3-layer, connection-oriented HDLC based communication profile
IEC 62056-9-7, Electricity metering data exchange – The DLMS/COSEM suite – Part 9-7:
Communication profile for TCP-UDP/IP networks
ISO/IEC/IEEE 8802:2014, Standard for Ethernet
ISO/IEC 12139-1:2009, Information technology – Telecommunications and information
exchange between systems – Power line communication (PLC) – High speed PLC medium
access control (MAC) and physical layer (PHY) – Part 1: General requirements

– 8 – IEC 62056-8-6:2017  IEC 2017
RFC 791, Internet Protocol, DARPA internet program protocol specification, 1981
RFC 1144, Compressing TCP/IP Headers for Low-Speed Serial Links, 1990
RFC 2460, Internet Protocol, Version 6 (IPv6) Specification, 1998
RFC 2508, Compressing IP/UDP/RTP Headers for Low-Speed Serial Links, 1999
RFC 3095, RObust Header Compression (ROHC): Framework and four profiles: RTP, UDP,
ESP, and uncompressed, 2001
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
adaptation layer
supporting layer between PHY/MAC layer of ISO/IEC 12139-1 and upper layer
3.2 Abbreviated terms
AA Application Association
ADPL Adaptation Layer
APDU Application Layer Protocol Data Unit
CMD Command
COSEM Companion Specification for Energy Metering
CPAS Common Part Adaptation Sublayer
DLMS Device Language Message Specification
DMT Discrete Multi-Tone
HDLC High-level Data Link Control
HES Head End System
HS-PLC High Speed Power Line Communication
IC Interface Class
IoT Internet of Things
IP Internet Protocol
IEEE Institute of Electrical and Electronics Engineers
ISO International Organization for Standardization
LLC Logical Link Control
LN Local Network
LNAP Local Network Access Points
MAC Medium Access Control
MPDU MAC Protocol Data Unit
NN Neighbourhood Network
NNAP Neighbourhood Network Access Points
PDU Protocol Data Unit
PHY Physical Layer
PLC Power Line Communication
SAP Service Access Point
SSAS Service Specific Adaptation Sublayer
STA Status
4 Targeted communication environments
The DLMS/COSEM High speed PLC (HS-PLC) ISO/IEC 12139-1 profile is intended for remote
data exchange on Neighbourhood Networks (NN) between Neighbourhood Network Access
Points (NNAPs) and metering devices or Local Network Access Points (LNAPs) using HS-PLC
technology over the low voltage electricity distribution network as a communication medium.
The functional reference architecture is shown in Figure 1.
Simple
Metering
consumer
device
display
Home automation
system
LNAP Local network access point
NNAP Neighbourhood network access point
HES Head end system
Not in scope
Power Line
of TC13
IEC
Figure 1 – Entities and interfaces of a smart metering
system using the terminology of IEC 62056-1-0
Metering devices – typically electricity meters – comprise application functions and
communication functions. They may be connected directly to the NNAP via the C interface, or
to an LNAP via the M interface, while the LNAP is connected to the NNAP via the C interface.
The LNAP function may be co-located with the metering functions.
WAN Wide Area Network
NN Neighbourhood Network
LN Local Network
– 10 – IEC 62056-8-6:2017  IEC 2017
A NNAP comprises gateway functions and it may comprise concentrator functions. Upstream,
it is connected to the metering Head End System (HES) using suitable communication media
and protocols.
Metering devices and LNAPs may communicate to different NNAPs, but to one NNAP only at
a time.
NNAPs and similarly LNAPs may communicate to each other, but it is out of the scope of this
document, which covers the C interface only.
When an NNAP has concentrator function it acts as a DLMS/COSEM client. When an NNAP
has gateway function only the HES acts as a DLMS/COSEM client. Metering devices or
LNAPs act as the DLMS/COSEM servers.
5 Use of the communication layers for this profile
5.1 Information related to the use of the standard specifying the lower layers
This communication profile uses the services of the PHY and MAC layers according to
ISO/IEC 12139-1:2009.More details can be found in 5.3.2 and 5.3.3.
5.2 Structure of the communication profile
The structure of this profile is shown in Figure 2. The adaptation layer supports the
connection of the DLMS/COSEM application layer to the MAC layer of ISO/IEC 12139-1:2009
via an HDLC based data link layer or via an IP based network layer. The adaptation layer
described in 5.4 supports both options. Devices implementing this standard may support just
one or the other option.
Processus d'application COSEM
IEC 62056-6-1, IEC 62056-6-2
DLMS/COSEM Application layer
IEC 62056-5-3
DLMS/COSEM Transport
HDLC based data link layer
layer for IP networks
IEC 62056-46
IEC 62056-4-7
Ipv4/Ipv6
Adaptation layer IEC 62056-8-6
PHY/MAC layer: High Speed PLC ISO/IEC 12139-1
IEC
Figure 2 – DLMS/COSEM High Speed PLC profile

5.3 Lower protocol layers and their use
5.3.1 Overview
Lower protocol layers of this profile consist of the physical layer and the MAC layer. They are
specified in ISO/IEC 12139-1:2009.
5.3.2 Physical layer
The physical layer provides the interface between the equipment and the physical
transmission medium that is the electricity distribution network. It transmits and receives
MPDUs between neighbour nodes by using the PLC technology defined in ISO/IEC 12139-
1:2009. It uses Discrete Multi-Tone (DMT) modulation in the frequency range from 2,15 MHz
up to 23,15 MHz and each tone has a bandwidth of 97,65625 kHz (theoretical) with the
exception of the bandwidth designated as the guard band in accordance with each national
regulation.
More details of the physical layer are specified in ISO/IEC 12139-1:2009, Clause 6.
5.3.3 MAC layer
The MAC layer handles access to the physical medium and physical device addressing. The
MAC layer of this profile is specified in ISO/IEC 12139-1:2009, Clause 7.
5.4 Service mapping and adaptation layers
5.4.1 Overview
The adaptation layer takes a role of effectively transmitting the HDLC based data link layer
frames, IPv4 (RFC 791) or IPv6 (RFC 2460) packets based on relevant specifications in
IEC 62056-46 or IEC 62056-4-7. The adaptation layer is connected to the MAC layer and to
the HDLC based data link layer or IPv4/IPv6 layer. It is composed of a Common Part
Adaptation Sublayer (CPAS) and a Service Specific Adaptation Sublayer (SSAS). The SSAS
has two types: IP Service Specific Adaptation Sublayer (IP SSAS) and HDLC Service Specific
Adaptation Sublayer (HDLC SSAS). The architecture of the adaptation sublayers is shown in
Figure 3.
HDLC based DLL IPv4/IPv6
IEC 62056-46 Network layer
HDLC SSAS IP SSAS
CPAS
Adaptation layer
PHY/MAC layer ISO/IEC 12139-1
IEC
Figure 3 – Adaptation layer architecture

– 12 – IEC 62056-8-6:2017  IEC 2017
5.4.2 CPAS
The CPAS transports a SSAS message (as payload) by adding a header to it. The SSAS
message may consist of an IP SSAS packet (assembled by the IP SSAS) or of a HDLC SSAS
frame (assembled by the HDLC SSAS). The structure of the CPAS frame is shown in Figure 4.
It corresponds to an Ethernet frame according to ISO/IEC/IEEE 8802:2014, where:
• DA is the destination CPAS address;
• SA is the source CPAS address;
• EtherType is used to identify the packet/frame type which is transported in the SSAS
message:
– IPv4 : 0x0800;
– IPv6 : 0x86DD;
– HDLC: project specific assignment.
DA SA Ether type SSAS message
6 Bytes 6 Bytes 2 Bytes
Header
CPAS frame
IEC
Figure 4 – CPAS frame structure
The mapping between IP addresses/HDLC addresses and CPAS DA/SA is supported by the
IP SSAS or the HDLC SSAS as applicable. The details of the mapping procedure are
implementation specific.
5.4.3 IP SSAS
5.4.3.1 Overview
The IP SSAS manages the mapping of IP packets to IP SSAS packets to be transported in the
SSAS message field of the CPAS frame; see Figure 4. There are two different types of IP
SSAS packets: the IP SSAS data packet (see 5.4.3.4) and the IP SSAS control packet (see
5.4.3.3).
The IP SSAS manages the mapping of IP packets to CPAS frames. In particular, the IP SSAS
performs the following functions:
• Address resolution: Mapping the IP addresses to the CPAS addresses.
5.4.3.2 IP header compression
A lot of IP header compression related technologies have been developed. The most popular
ones are Van Jacobson header compression (RFC 1144), IP header compression (RFC 2508)
and ROHC (RFC 3095). Since the IP header compression related technologies are processed
in the IP layer, IP SSAS does not take care of those technologies. Nonetheless the IP SSAS,
at least, needs to recognize IP version of the received IP packet and determine whether the
compression will be applied or not by using IP_Header_Comp_Type field defined in Table 3.

5.4.3.3 IP SSAS control packet
The IP SSAS control packet is used for address resolution and it is configured as specified in
Figure 5 and Table 1.
Octets
1 1 1 4 or 16 16 4 or 16 16
Packet_ CTL_ IP_ Sender_ Sender_ Target_ Target_
Type Type Len IP_ADDR CPAS_ADDR IP_ADDR CPAS_ADDR
IEC
Figure 5 – IP SSAS control packet
Table 1 – IP SSAS control packet format Inconsistencies! IP_Len
Length
Name Data type Description
(octets)
0x02: IPv4 Control packet of IP SSAS
Packet_Type 1 enum
0x03: IPv6 Control packet of IP SSAS
0x00: AR_Request_CMD
CTL_Type 1 enum
0x01: AR_Response_CMD
Sender_IP_ADDR 4 or 16 long-unsigned Sender’s IP address
Sender_CPAS_ADDR 6 long-unsigned Sender’s CPAS address
Target_IP_ADDR 4 or 16 long-unsigned Target’s IP address
Target_CPAS_ADDR 16 long-unsigned Target’s CPAS address

• In case of AR_Request_CMD requesting Address Resolution, CTL_Type is set to 0x00. In
case of AR_Response_CMD responding to the request, CTL_Type is set to 0x01;
• AR_Request_CMD packet is generated when the sender node has the IP address of the
target node, but does not know the CPAS address of the target node. The sender node
that generates the AR_Request_CMD packet puts its information into the Sender_IP_Len,
Sender_IP_ADDR, Sender_CPAS_ADDR fields and puts the target node’s IP address
information into the Target_IP_Len and Target_IP_ADDR fields. The Target_CPAS_ADDR
field which the sender node tries to find out is filled with a series of 0xFFs;
• The target node which received the AR_Request_CMD packet responds with
AR_Response_CMD packet putting its CPAS address into the Target_CPAS_ADDR field.
This time, all the other address fields except for the Target_CPAS_ADDR, such as the
Sender_IP_Len, Sender_IP_ADDR, Sender_CPAS_ADDR, Target_IP_Len, Target_IP,
ADDR, are filled with the same values from the AR_Request_CMD packet;
• AR_Request_CMD packet is transmitted in broadcast mode;
• AR_Response_CMD packet is transmitted in unicast mode.
5.4.3.4 IP SSAS data packet
The IP SSAS data packet is used to transport the IP Packets received from the IPv4/IPv6
network layer. The structure is shown in Figure 6 and Table 2.

Octets 1 1 2 N
Packet_Type Comp_Type IP_Data_Len IP_Data
IEC
Figure 6 – IP SSAS data packet

– 14 – IEC 62056-8-6:2017  IEC 2017
Table 2 – IP SSAS data packet format
Length
Name Data Type Description
(octets)
(0) IPv4 data packet of IP SSAS
Packet_Type 1 enum
(1) IPv6 data packet of IP SSAS
(0) General IPv4 packet (No compression)
(1) General IPv6 packet (No compression)
Comp_Type 1 enum (2) Van Jacobson header compression (RFC 1144)
(3) IP header compression (RFC 2508)
(4) ROHC (RFC 3095)
IP_Data_Len 2 long-unsigned
Length in octets of the field IP_Data
IP_Data N octet-string The general IP packet or the compressed IP packet

• The enumeration value of the Packet_Type field identifies the packet type of the IP SSAS
Data packet;
• The value of the Comp_Type field identifies the IP packet IP_Header_Comp_Type
parameter value of ADPL_IP_Data.request;
• The value of the IP_Data_Len field identifies the length in the octets of the IP_Data;
• IP_Data field is a whole IP packet conveyed by IP SSAS. It can be a general IPv4 packet,
a general IPv6 packet, a header-compressed IPv4 packet or a header-compressed IPv6
packet.
5.4.3.5 IP SSAS Data services
5.4.3.5.1 Overview
IP SSAS Data services are used for transmitting the data received from the IP layer to the
destination. This service is used in Unicast, Broadcast or Multicast types:
• Unicast: Looking up the Address Resolution Table which is managed by IP SSAS, if the
matched CPAS address is found, transfers the packet in Unicast method provided by MAC
layer (ISO/IEC 12139-1:2009);
• Broadcast: transfers the packet in Broadcast method provided by MAC layer
(ISO/IEC 12139-1:2009);
• Multicast: The IP multicast packet is transmitted in Broadcast method provided by MAC
layer (ISO/IEC 12139-1:2009) because the MAC layer does not support Multicast.
Regarding the data service, IP SSAS provides the network layer with basic service primitives
related to data transmission and reception. In real implementations, additional services and/or
parameters may be necessary; however those are out of the scope of this document.
5.4.3.5.2 ADPL_IP_Data.request
Function
This primitive is invoked when an IP packet has to be transmitted to the peer IP layer.

Service Parameters
ADPL_IP_Data.request
(
IP_PDU,
Target_IP_Address,
IP_Header_Comp_Type
)
IP_PDU (Internet Protocol_Protocol Data Unit) is the IP packet to be sent.
Target_IP_Address is the IP address of the receiving station. It may be a unicast, broadcast
or multicast IP address.
IP_Header_Comp_Type is a parameter which represents the IP header compression
information, and has values as shown in Table 3. For more details, refer to 5.4.3.2, IP header
compression.
Table 3 – Values for IP_Header_Comp_Type
Value(enum) Description
0 General IPv4 packet (No compression)
1 General IPv6 packet (No compression)
2 Compressed IP packet by Van Jacobson header compression (RFC 1144)
3 Compressed IP packet by IP header compression (RFC 2508)
4 Compressed IP packet by ROHC (RFC 3095)

5.4.3.5.3 ADPL_IP_Data.confirm
Function
This primitive is generated locally for signalling to the requestor the result of the data transfer
request.
Service Parameters
ADPL_IP_Data.confirm
(
IP_PDU,
Result
)
IP_PDU is the IP packet that was to be sent.
Result indicates whether the packet was sent or an error occurred. It takes a value from
Table 4.
– 16 – IEC 62056-8-6:2017  IEC 2017
Table 4 – Valid range of the Transmission_status value
Name Type Valid range Description
OK No error has been found
TU Resources temporally unavailable
NI Resources not implemented or inactivated
Transmission_status Enumeration
HF Hardware failure
SE Syntax error
5.4.3.5.4 ADPL_IP_Data.indication
Function
This service primitive is used to transfer the received data from the IP SSAS to the IP layer.
Service Parameters
ADPL_IP_Data.indication
(
IP_PDU,
IP_Header_Comp_Type
)
IP_PDU is the IP packet that was received.
IP_Header_Comp_Type is a parameter which represents the IP header compression
information, and has values as shown in Table 3.
5.4.4 HDLC SSAS
5.4.4.1 Overview
The HDLC SSAS manages the mapping of HDLC frames to HDLC SSAS frames to be
transported in the SSAS message field of the CPAS frame (see Figure 4). There is only one
type of HDLC SSAS frame used for data transport.
Unlike IP SSAS, HDLC SSAS does not perform address resolution between CPAS addresses
and HDLC addresses since the HDLC addresses are not unique within overall PLC network.
The address mapping table, instead, is maintained and managed by LNAP or NNAP, which
will find a target metering device by using both CPAS address and the corresponding HDLC
address.
5.4.4.2 HDLC SSAS frame
The HDLC SSAS frame is used to transmit a HDLC frame, and is configured as Figure 7 and
Table 5.
Octets
2 2 2 2 1 1 N
HDLC frame or
Frame_ SEQ_
RSVD LEN CMD STA Response to HDLC addresses
Type Number
request
IEC
Figure 7 – HDLC SSAS Frame
Table 5 – HDLC SSAS Frame format
Name Length Data Description
(octets) Type
long-unsigned
Frame_Type 2 Frame type of HDLC SSAS frame is set to 0x0005.
SEQ_Number 2 long-unsigned Sequence number
RSVD 2 long-unsigned Reserved
long-unsigned
LEN 2 HDLC Frame length in octets
CMD 1 enum Command
STA 1 enum Status
HDLC frame HDLC frame (when CMD is 0x10 and STA is 0x30)
or or
N octet-string
Response to HDLC Response to HDLC addresses request (when CMD is 0x41
addresses request and STA is 0x31)

CMD (Command) and STA (Status) fields are used for delivering HDLC frame as well as for
additional management services such as response time-out and HDLC address scanning (in
case of multi-drop configuration). The HDLC address scanning process is done by HDLC
SSAS layer. The purpose of the HDLC address scanning is to collect the HDLC addresses of
multiple meters which are connected to a PLC station via serial interface, that is, Multi-drop
Configuration. Table 6 below shows the usage of CMD and STA fields.
Table 6 – Usage of CMD and STA fields
CMD STA Description
0x10 0x30 HDLC frame delivery
Acknowledgement for HDLC frame reception.
Note: The SEQ_Number value used in this acknowledgement frame is the
0x10 0x31
same with the one used in the corresponding HDLC frame delivery frame
(CMD: 0x10, STA:0x30)
0x30 0x32 Response Time-out (Metering device → LNAP or NNAP)
Request for sending HDLC addresses scanned by the PLC station in case
0x41 0x30
of multi-drop configuration (1 PLC station: multiple meters)
0x41 0x31 Response to the HDLC addresses

CMD of 0x41 and STA of 0x30, 0x31 are used when LANP or NNAP request a PLC station to
send HDLC addresses of multiple meters which are connected to the PLC station via serial
multi-drop configuration. A response message to HDLC addresses request is configured as
shown in Figure 8.
Number of scanned HDLC HDLC HDLC
Field Name Status …
addresses Address 1 Address n
0x30: Scanning
When Status field is 0x31
Lower HDLC Lower HDLC
Complete
(Scanning in process), the
Description
address of … address of
HDLC addresses scanned up
0x31: Scanning in
Meter #1 Meter #n
to the instance is delivered.
process
Length
1 1 1 or 2 … 1 or 2
(octets)
IEC
Figure 8 – Message configuration for response to HDLC addresses request

– 18 – IEC 62056-8-6:2017  IEC 2017
5.4.4.3 HDLC SSAS data services
5.4.4.3.1 ADPL_HDLC_Data.request
Function
The service user layer invokes this service primitive to initiate a data transfer to its peer layer.
Service Parameters
ADPL_HDLC_Data.request
(
Data
)
Data is the HDLC frame to be sent.
5.4.4.3.2 ADPL_HDLC_Data.confirm
Function
This service primitive is generated for signalling to the requestor the result of the data transfer
request. It contains the performance result of the ADPL_HDLC_Data.request and a HDLC
frame that has been sent.
Service Parameters
ADPL_HDLC_Data.confirm
(
Data,
Result
)
Data is the HDLC frame to be sent.
Result indicates whether the Data was sent successfully or an error occurred. It takes a value
from Table 4.
5.4.4.3.3 ADPL_HDLC_Data.indication
Function
This service primitive is used to transfer the received data from the HDLC SSAS to the HDLC
based data link layer.
Upon the arrival of a new HDLC frame from the peer, the primitive is generated.
Service Parameters
ADPL_HDLC_Data.indication
(
Data
)
Data is the HDLC frame received.

5.5 Reg
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