IEC PAS 61158-4-22:2009

IEC/PAS 61158-4-22 ®
Edition 1.0 2009-08
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Industrial communication networks – Fieldbus specifications –
Part 4–22: Data-link layer protocol specification – Type SNpTYPE elements

IEC/PAS 61158-4-22:2009(E)
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IEC/PAS 61158-4-22 ®
Edition 1.0 2009-08
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Industrial communication networks – Fieldbus specifications –
Part 4–22: Data-link layer protocol specification – Type SNpTYPE elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XB
ICS 25.040; 35.100.20 ISBN 978-2-88910-795-7
– 2 – PAS 61158-4-22 © IEC:2009(E)

CONTENTS
FOREWORD.6

1 Scope.9

1.1 General .9

1.2 Specifications.9

1.3 Procedures.9

1.4 Applicability.9

1.5 Conformance.10

2 Normative references .10
3 Terms, definitions, symbols, abbreviations and conventions .10
3.1 Reference model terms and definitions.10
3.2 Service convention terms and definitions.12
3.3 Common terms and definitions .13
3.4 Additional Type SNpTYPE definitions .14
3.5 Common symbols and abbreviations .16
3.6 Additional Type SNpTYPE symbols and abbreviations.17
3.7 Conventions .20
3.7.1 Abstract syntax conventions .20
3.7.2 Protocol machine description conventions .20
4 DL-protocol overview.20
4.1 Operating principle .20
4.2 Communication model .21
4.2.1 Overview .21
4.2.2 RTFL device reference model.21
4.2.3 RTFN device reference model .22
4.3 Topology .23
4.3.1 RTFL topology.23
4.3.2 RTFN topology .23
4.4 Frame processing.23
4.4.1 Communication model RTFL.23
4.4.2 Communication model RTFN .23
4.5 General communication mechanisms .24
4.5.1 Cyclic data channel (CDC).24

4.5.2 Message channel (MSC).24
4.6 Gateway.24
4.7 Interaction models.25
4.7.1 Overview .25
4.7.2 Producer-consumer .25
4.7.3 Publisher-subscriber.25
5 DLPDU structure .25
5.1 Overview .25
5.2 Data types and encoding rules .25
5.2.1 Overview .25
5.2.2 Transfer syntax for bit sequences .25
5.2.3 Unsigned Integer .26
5.2.4 Signed Integer .26
5.2.5 Octet Array.27

PAS 61158-4-22 © IEC:2009(E) – 3 –

5.3 DLPDU identification .27

5.4 General DLPDU structure.27

5.4.1 Type SNpTYPE frame inside an Ethernet frame.27

5.4.2 Type SNpTYPE frame inside a VLAN tagged Ethernet frame.28

5.4.3 Type SNpTYPE frame inside an UDP datagram.28

5.4.4 Type SNpTYPE frame structure.29

5.5 Communication management DLPDUs .30

5.5.1 Network verification DLPDUs.30

5.5.2 RTFN scan network read DLPDUs.31

5.5.3 Identification data .31

5.5.4 RTFN connection management DLPDU .34
5.5.5 ID data .34
5.5.6 RTFL control DLPDU .35
5.5.7 RTFL configuration DLPDUs.35
5.6 Cyclic data channel (CDC) DLPDUs .36
5.6.1 Cyclic data channel line (CDCL) DLPDU.36
5.6.2 Cyclic data channel network (CDCN) DLPDU .37
5.7 Cyclic data channel (CDC) DLPDU data .37
5.7.1 Cyclic data channel (CDC) DLPDU data arrangement.37
5.7.2 Cyclic data channel (CDC) DLPDU data .37
5.8 Message channel (MSC) DLPDUs .38
5.8.1 Message channel line (MSCL) DLPDU.38
5.8.2 Message channel network (MSCN) DLPDU .39
5.9 Message channel DLPDU data - MSC message transfer protocol (MSC-MTP).39
5.9.1 Overview .39
5.9.2 MSC-MTP frame.39
5.9.3 MSC-MTP frame data .40
5.9.4 MSC-MTP message data encoding .42
5.10 Time synchronization .42
5.10.1 DelayMeasurement start.42
5.10.2 DelayMeasurement read.43
5.10.3 PCS configuration.43
5.10.4 Time synchronization service.43
6 Telegram timing and DLPDU handling .44
6.1 Communication mechanism.44

6.1.1 Communication model RTFL.44
6.1.2 Communication model RTFN .45
6.2 Device synchronization.46
6.2.1 Communication model RTFL – precise clock synchronization .46
6.2.2 Communication model RTFN .47
7 Type SNpTYPE protocol machines .47
7.1 RTFL device protocol machines.47
7.1.1 Overview .47
7.1.2 PortX protocol machine (PortX PM) .48
7.1.3 Frame handling protocol machine (FHPM) .48
7.1.4 Cyclic data channel line protocol machine (CDCLPM).50
7.1.5 Message channel line protocol machine (MSCLPM).52
7.1.6 Message channel message transfer protocol protocol machine (MSC-
MTP PM) .54

– 4 – PAS 61158-4-22 © IEC:2009(E)

7.1.7 Net management protocol machine (NMPM) .55

7.1.8 Precise clock synchronization (PCS) .57

7.2 RTFN device protocol machines .60

7.2.1 Overview .60

7.2.2 Cyclic data channel network protocol machine (CDCNPM) .60

7.2.3 Message channel network protocol machine (MSCNPM) .60

7.2.4 Message channel message transfer protocol protocol machine (MSC-

MTP PM) .60

7.2.5 Net management protocol machine (NMPM) .61

7.3 Message channel - message transfer protocol (MSC-MTP) .62

7.3.1 Overview .62
7.3.2 MSC-MTP PM.62

Figure 1 – RTFL device reference model .22
Figure 2 – RTFN device reference model.22
Figure 3 – Block diagram of hardware.45
Figure 4 – Frame sequence .45
Figure 5 – Communication relationship RTFN device .46
Figure 6 – Overview RTFL device protocol machines.48
Figure 7 – Protocol machine send DLPDU procedure.49
Figure 8 – Protocol machine receive DLPDU procedure.49
Figure 9 – CDCL send cyclic data sequence .50
Figure 10 – CDCL receive cyclic data sequence .51
Figure 11 – MSCL send sequence .53
Figure 12 – MSCL receive sequence.54
Figure 13 – Network management protocol machine .55
Figure 14 – Net management sequence at system boot up .56
Figure 15 – Initialization sequence ordinary device .57
Figure 16 – PCS configuration sequence .58
Figure 17 – Delay measurement principle .59
Figure 18 – Overview RTFN device protocol machines .60
Figure 19 – CDCN connection setup and release .61
Figure 20 – CDCN unpulish data.62
Figure 21 – Segmentation sequence .63
Figure 22 – Expedited transfer sequence.64
Figure 23 – Toggling from expedited transfer to segmented transfer .64
Figure 24 – Segmentation sequence for broad- or multicast message.65

Table 1 – PDU element definition.20
Table 2 – Conventions for protocol machine description .20
Table 3 – Transfer syntax for bit sequences.26
Table 4 – Transfer syntax for data type Unsignedn .26
Table 5 – Transfer syntax for data type Signedn .27
Table 6 – Type SNpTYPE frame inside an Ethernet frame .27
Table 7 – Type SNpTYPE frame inside a VLAN tagged Ethernet frame.28

PAS 61158-4-22 © IEC:2009(E) – 5 –

Table 8 – Type SNpTYPE frame inside an UDP datagram .29

Table 9 – General structure of a Type SNpTYPE frame .29

Table 10 – DLPDU header structure .30

Table 11 – Network verification prepare DLPDU .30

Table 12 – Network verification environment DLPDU .30

Table 13 – Network verification information DLPDU .30

Table 14 – Network verification acknowledgement DLPDU.31

Table 15 – RTFN scan network read request DLPDU.31

Table 16 – RTFN scan network read response DLPDU .31
Table 17 – Identification data.32
Table 18 – PhyLinkPortX .33
Table 19 – RTF support .33
Table 20 – UseDHCP.33
Table 21 – DeviceRole.34
Table 22 – RTFN connection management DLPDU .34
Table 23 – CDCN connection still alive DLPDU.34
Table 24 – ID data .35
Table 25 – RTFL control DLPDU.35
Table 26 – RTFL configuration DLPDU .36
Table 27 – RTFL configuration acknowledgement DLPDU .36
Table 28 – CDCL DLPDU.37
Table 29 – CDCN DLPDU .37
Table 30 – CDC DLPDU data arrangement .37
Table 31 – CDC DLPDU data.38
Table 32 – MSCL DLPDU .38
Table 33 – MSCL control .39
Table 34 – MSCN DLPDU .39
Table 35 – MSC-MTP frame structure .40
Table 36 – Address type .40
Table 37 – MSC-MTP Init structure .41
Table 38 – MSC-MTP Init_Fast structure .41

Table 39 – MSC-MTP Send structure.41
Table 40 – MSC-MTP Acknowledgement structure.42
Table 41 – MSC-MTP Abort structure.42
Table 42 – Data structure of a message.42
Table 43 – DelayMeasurement start encoding.43
Table 44 – DelayMeasurement read encoding.43
Table 45 – PCS configuration encoding .43
Table 46 – Time synchronization service request.43
Table 47 – Time synchronization service response .44

– 6 – PAS 61158-4-22 © IEC:2009(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
INDUSTRIAL COMMUNICATION NETWORKS –

FIELDBUS SPECIFICATIONS –
Part 4–22: Data-link layer protocol specification –

Type SNpTYPE 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
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
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6) All users should ensure that they have the latest edition of this publication.
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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.

A PAS is a technical specification not fulfilling the requirements for a standard, but made
available to the public.
IEC-PAS 61158-4-22 has been processed by subcommittee 65C: Industrial networks, of IEC
technical committee 65: Industrial-process measurement, control and automation.
The text of this PAS is based on the This PAS was approved for
following document: publication by the P-members of the
committee concerned as indicated in
the following document
Draft PAS Report on voting
65C/530/PAS 65C/534/RVD
Following publication of this PAS, which is a pre-standard publication, the technical committee
or subcommittee concerned may transform it into an International Standard.

PAS 61158-4-22 © IEC:2009(E) – 7 –

This PAS shall remain valid for an initial maximum period of 3 years starting from the

publication date. The validity may be extended for a single 3-year period, following which it

shall be revised to become another type of normative document, or shall be withdrawn.

The list of all the parts of the IEC 61158 series, under the general title Industrial

communication networks – Fieldbus specifications, can be found on the IEC web site.

– 8 – PAS 61158-4-22 © IEC:2009(E)

INTRODUCTION
This PAS contains an additional profile – SNpTYPE – which may be integrated into a future

new edition of the IEC 61158-4 series.

PAS 61158-4-22 © IEC:2009(E) – 9 –

INDUSTRIAL COMMUNICATION NETWORKS –

FIELDBUS SPECIFICATIONS –
Part 4–22: Data-link layer protocol specification –

Type SNpTYPE 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 part of IEC 61158-4 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) the structure of the fieldbus DLPDUs used for the transfer of data and control information
by the protocol of this part of IEC 61158-4, 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.
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.

– 10 – PAS 61158-4-22 © IEC:2009(E)

1.5 Conformance
This part of IEC 61158-4 also specifies conformance requirements for systems implementing

these procedures.
This part of IEC 61158-4 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 61588, Precision clock synchronization protocol for networked measurement and control
system
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 8802-3:2000, 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
IETF RFC 791, Internet Protocol
IEEE 802.1Q, IEEE Standard for Local and metropolitan area networks – Virtual Bridged
Local Area Networks
3 Terms, definitions, symbols, abbreviations and conventions

3.1 Reference model terms and definitions
This part of IEC 61158-4 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 acknowledgement
[7498-1]
3.1.2 DL-address [7498-3]
3.1.3 DL-address-mapping [7498-1]
3.1.4 called-DL-address [7498-3]
3.1.5 calling-DL-address
[7498-3]
PAS 61158-4-22 © IEC:2009(E) – 11 –

3.1.6 DL-connection [7498-1]
3.1.7 DL-connection-end-point [7498-1]

3.1.8 DL-connection-end-point-identifier [7498-1]

3.1.9 DL-connection-mode transmission [7498-1]

3.1.10 DL-connectionless-mode transmission [7498-1]

3.1.11 decentralized multi-end-point-connection [7498-1]
3.1.12 DL-duplex-transmission [7498-1]
3.1.13 (N)-entity [7498-1]
DL-entity (N=2)
Ph-entity (N=1)
3.1.14 flow control [7498-1]
3.1.15 (N)-layer [7498-1]
DL-layer (N=2)
Ph-layer (N=1)
3.1.16 layer-management [7498-1]
3.1.17 DL-local-view [7498-3]
3.1.18 multi-endpoint-connection [7498-1]
3.1.19 DL-name [7498-3]
3.1.20 naming-(addressing)-domain [7498-3]
3.1.21 peer-entities [7498-1]
3.1.22 primitive name [7498-3]
3.1.23 DL-protocol [7498-1]
3.1.24 DL-protocol-connection-identifier [7498-1]
3.1.25 DL-protocol-control information [7498-1]
3.1.26 DL-protocol-data-unit [7498-1]
3.1.27 DL-protocol-version-identifier [7498-1]
3.1.28 DL-relay [7498-1]
3.1.29 reassembling [7498-1]
3.1.30 reset [7498-1]
– 12 – PAS 61158-4-22 © IEC:2009(E)

3.1.31 responding-DL-address [7498-3]

3.1.32 routing [7498-1]
3.1.33 segmenting [7498-1]
3.1.34 sequencing [7498-1]
3.1.35 (N)-service [7498-1]
DL-service (N=2)
Ph-service (N=1)
3.1.36 (N)-service-access-point [7498-1]
DL-service-access-point (N=2)
Ph-service-access-point (N=1)
3.1.37 DL-service-access-point-address [7498-3]
3.1.38 DL-service-connection-identifier [7498-1]
3.1.39 DL-service-data-unit [7498-1]
3.1.40 DL-simplex-transmission [7498-1]
3.1.41 DL-subsystem [7498-1]
3.1.42 systems-management [7498-1]
3.1.43 DL-user-data [7498-1]
3.2 Service convention terms and definitions
This part of IEC 61158-4 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

PAS 61158-4-22 © IEC:2009(E) – 13 –

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 Common terms and definitions
NOTE Many definitions are common to more than one protocol Type; they are not necessarily used by all protocol
Types.
3.3.1
DL-segment
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
3.3.2
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.
3.3.3
frame
denigrated synonym for DLPDU
3.3.4
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.

– 14 – PAS 61158-4-22 © IEC:2009(E)

3.3.5
sending DLS-user
DL-service user that acts as a source of DL-user-data

3.4 Additional Type SNpTYPE definitions

3.4.1
acyclic data
data which is transferred from time to time for dedicated purposes

3.4.2
bit
unit of information consisting of a 1 or a 0. This is the smallest data unit that can be
transmitted
3.4.3
cell
synonym for a single DL-segment which uses RTFL communication model
3.4.4
communication cycle
fixed time period between which the root device issues empty frames for cyclic
communication initiation in which data is transmitted utilizing CDC and MSC
3.4.5
cycle time
duration of a communication cycle
3.4.6
cyclic
events which repeat in a regular and repetitive manner
3.4.7
cyclic communication
periodic exchange of frames
3.4.8
cyclic data
data which is transferred in a regular and repetitive manner for dedicated purposes
3.4.9
cyclic data channel (CDC)
part of one or more frames, which is reserved for cyclic data
3.4.10
data
generic term used to refer to any information carried over a fieldbus
3.4.11
device
physical entity connected to the fieldbus
3.4.12
error
discrepancy between a computed, observed or measured value or condition and the specified
or theoretically correct value or condition

PAS 61158-4-22 © IEC:2009(E) – 15 –

3.4.13
gateway
device acting as a linking element between different protocols

3.4.14
inter-cell communication
communication between a RTFL device and a RTFN device or communication between a

RTFL device and another RTFL device in different cells linked by RTFN

3.4.15
interface
shared boundary between two functional units, defined by functional characteristics, signal
characteristic, or other characteristics as appropriate
3.4.16
intra-cell communication
communication between a RTFL device and another RTFL device in the same cell
3.4.17
link
synonym for DL-segment
3.4.18
ma st er c lo ck
global time base for the PCS mechanism
3.4.19
message
ordered sequence of octets intended to convey data
3.4.20
message channel (MSC)
part of one or more frames, which is reserved for acyclic data
3.4.21
network
set of devices connected by some type of communication medium, including any intervening
repeaters, bridges, routers and lower-layer gateways
3.4.22
open network
any Ethernet-based network with no further restrictions
3.4.23
ordinary device (OD)
slave in the communication system, which utilizes RTFL for cyclic and acyclic data
interchange with other ODs in the same logical double line
3.4.24
precise clock synchronization (PCS)
mechanism to synchronize clocks of RTFL devices and maintain a global time base
3.4.25
process data
data designated to be transferred cyclically or acyclically for the purpose of processing

– 16 – PAS 61158-4-22 © IEC:2009(E)

3.4.26
process data object
dedicated data object(s) designated to be transferred cyclically or acyclically for the purpose

of processing
3.4.27
protocol
convention about the data formats, time sequences, and error correction in the data exchange

of communication systems
3.4.28
root device (RD)
master in the communication system, which organises, initiates and controls the RTFL cyclic
and acyclic data interchange for one logical double line
3.4.29
real time frame line (RTFL)
communication model for communication with high real time requirements
3.4.30
real time frame network (RTFN)
communication model for communication with low real time requirements
3.4.31
switch
MAC bridge as defined in 802.1D
3.4.32
round trip time
transmission time needed by a DLPDU from the RD to the last OD in forward and backward
direction
3.4.33
timing signal
time-based indication of the occurrence of an event, commonly as an interrupt signal, used for
DL-user synchronization
3.4.34
topology
physical network architecture with respect to the connection between the stations of the
communication system
3.5 Common symbols and abbreviations
NOTE Many symbols and abbreviations are common to more than one protocol Type; they are not necessarily
used by all protocol Types.
3.5.1 CIDR Classless Inter-Domain Routing
3.5.2 DHCP Dynamic Host Configuration Protocol
3.5.3 DL- Data-link layer (as a prefix)
3.5.4 DLC DL-connection
3.5.5 DLCEP DL-connection-end-point

PAS 61158-4-22 © IEC:2009(E) – 17 –

3.5.6 DLE DL-entity
3.5.7 DLL DL-layer
3.5.8 DLPCI DL-protocol-control-information

3.5.9 DLPDU DL-protocol-data-unit

3.5.10 DLM DL-management
3.5.11 DLME DL-management entity
3.5.12 DLMS DL-management service
3.5.13 DLPDU DL-protocol-data-unit
3.5.14 DLS DL-service
3.5.15 DLSAP DL-service-access-point
3.5.16 DLSDU DL-service-data-unit
3.5.17 DNS Domain name server
3.5.18 FCS Frame check sequence
3.5.19 FIFO First-in first-out
3.5.20 IANA Internet Assigned Numbers Authority
3.5.21 IEEE Institute of Electrical and Electronics Engineers
3.5.22 IETF Internet Engineering Task Force
3.5.23 OSI Open systems interconnection
3.5.24 Ph- Physical layer (as a prefix)

3.5.25 PhE Ph-entity
3.5.26 PhL Ph-layer
3.5.27 QoS Quality of service
3.5.28 RFC Request for comments
3.5.29 UTF Unicode transformation format
3.6 Additional Type SNpTYPE symbols and abbreviations
3.6.1 ACK Acknowledgement
3.6.2 ADL ACK data length
– 18 – PAS 61158-4-22 © IEC:2009(E)

3.6.3 CDC Cyclic data channel
3.6.4 CDCL CDC line
3.6.5 CDCLPM CDCL protocol machine

3.6.6 CDCN CDC network
3.6.7 CDCNPM CDCN protocol machine

3.6.8 CDCS CDC send
3.6.9 CL Communication layer
3.6.10 CMD Command
3.6.11 DA Device address or destination address
3.6.12 DMR Delay measurement read
3.6.13 DMS Delay measurement send
3.6.14 FHPM Frame handling protocol machine
3.6.15 ID Identification
3.6.16 IP Internet protocol
3.6.17 IPv4 IP version 4
3.6.18 IPv6 IP version 6
3.6.19 IRQ Interrupt request
3.6.20 MAC Medium access control
3.6.21 MC Master clock
3.6.22 MSC-MTP Message channel message transfer protocol
3.6.23 MSC Message channel
3.6.24 MSCL MSC line
3.6.25 MSCLPM MSCL protocol machine
3.6.26 MSCN MSC network
3.6.27 MSCNPM MSCN protocol machine
3.6.28 MSCR MSC read
PAS 61158-4-22 © IEC:2009(E) – 19 –

3.6.29 MSCS MSC send
3.6.30 MSS Maximum segment size

3.6.31 NMPM Net management protocol machine

3.6.32 NV Network verification

3.6.33 OD Ordinary device
3.6.34 PD Previous device
3.6.35 PID Packet ID
3.6.36 PCS Precise clock synchronization
3.6.37 PCSC PCS configuration
3.6.38 PM Protocol machine
3.6.39 RD Root device
3.6.40 RTF Real time frame
3.6.41 RTFL Real time frame line
3.6.42 RTFLCFG RTFL configuration
3.6.43 RTFLCTL RTFL control
3.6.44 RTFN Real time frame network
3.6.45 RTFNCS RTFN connection setup
3.6.46 RTFNCR RTFN connection release
3.6.47 RTFNSNR RTFN Scan network read

3.6.48 RX Receive direction
3.6.49 SA Source address
3.6.50 SYNC Synchronization
3.6.51 SYNC_START SYNC start
3.6.52 SYNC_STOP SYNC stop
3.6.53 TCP Transmission control protocol
3.6.54 TSU Time stamping unit
– 20 – PAS 61158-4-22 © IEC:2009(E)

3.6.55 TX Transmit direction
3.6.56 UDP User datagram protocol

3.7 Conventions
3.7.1 Abstract syntax conventions

The data types BYTE and WORD used with
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