ISO/IEC 14908-1:2012

INTERNATIONAL ISO/IEC
STANDARD 14908-1
First edition
2012-11-01
Information technology — Control
network protocol —
Part 1:
Protocol stack
Technologies de l'information — Protocole de réseau de contrôle —
Partie 1: Pile de protocole
Reference number
©
ISO/IEC 2012
©  ISO/IEC 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO/IEC 2012 — All rights reserved

- 1 - 14908-1 © ISO/IEC:2012 (E)
Contents          page
Foreword . 7
Introduction . 8
1  Scope . 9
2  Normative references . 9
3  Terms and definitions . 9
4  Symbols and abbreviations . 11
4.1  Symbols and graphical representations . 11
4.2  Abbreviations . 12
5  Overview of protocol layering . 13
6  MAC sublayer . 15
6.1  Service provided . 15
6.2  Interface to the link layer . 15
6.3  Interface to the physical layer . 16
6.4  MPDU format . 17
6.5  Predictive p-persistent CSMA — overview description . 17
6.6  Idle channel detection . 18
6.7  Randomising . 19
6.8  Backlog estimation . 19
6.9  Optional priority . 20
6.10  Optional collision detection . 21
6.11  Beta1, Beta2 and Preamble Timings . 21
7  Link layer . 23
7.1  Assumptions . 23
7.2  Service provided . 24
7.3  CRC . 24
7.4  Transmit algorithm . 25
8  Network layer . 26
8.1  Assumptions . 26
8.2  Service provided . 27
8.3  Service interface . 27
8.4  Internal structuring of the network layer . 28
8.5  NPDU format . 28
8.6  Address recognition . 29
8.7  Routers . 29
8.8  Routing algorithm . 30
8.9  Learning algorithm — subnets . 30
9  Transaction control sublayer . 30
9.1  Assumptions . 30
9.2  Service provided . 31
9.3  Service interface . 31
9.4  State variables . 31
9.5  Transaction control algorithm . 32
10  Transport layer . 32
10.1  Assumptions . 32
10.2  Service provided . 32
10.3  Service interface . 33
10.4  TPDU types and formats . 33

14908-1 © ISO/IEC:2012 (E) - 2 -
10.5  Protocol diagram . 35
10.6  Transport protocol state variables . 35
10.7  Send algorithm . 35
10.8  Receive algorithm . 36
10.9  Receive transaction record pool size and configuration engineering . 36
10.9.1  General . 36
10.9.2  Number of retries . 36
10.9.3  Transport layer timers. 37
11  Session layer . 38
11.1  Assumptions . 38
11.2  Service Provided . 38
11.3  Service interface . 39
11.4  Internal structure of the session layer . 40
11.5  SPDU types and formats . 41
11.6  Protocol timing diagrams . 42
11.7  Request-response state variables . 44
11.8  Request-response protocol — client part . 45
11.9  Request-response protocol — server part . 45
11.10  Request-response protocol timers . 45
11.11  Authentication protocol . 46
11.12  Encryption algorithm . 46
11.13  Retries and the role of the checksum function . 46
11.14  Random Number Generation . 47
11.15  Using Authentication . 47
12  Presentation/application layer . 47
12.1  Assumptions . 47
12.2  Service provided . 47
12.3  Service interface . 48
12.4  APDU types and formats . 49
12.5  Protocol diagrams . 50
12.6  Application protocol state variables . 51
12.7  Request - response messaging in offline state . 51
12.8  Network variables . 52
12.8.1  General . 52
12.8.2  Network variable processing . 52
12.9  Error notification to the application program . 53
12.9.1  General . 53
12.9.2  Error notification for messages . 53
12.9.3  Error notification for network variables . 53
13  Network management & diagnostics . 53
13.1  Assumptions . 53
13.2  Services provided . 54
13.3  Network management and diagnostics application structure . 54
13.4  Node states . 54
13.5  Using the network management services. 55
13.5.1  General . 55
13.5.2  Addressing considerations . 55
13.5.3  Making network configuration changes . 56
13.5.4  Downloading an Application Program . 56
13.5.5  Error handling conditions (informative) . 56
13.6  Using router network management commands . 59
13.7  NMPDU formats and types . 60
13.7.1  General . 60
13.7.2  Query ID . 60
13.7.3  Respond to query . 61
13.7.4  Update domain . 61
13.7.5  Leave domain . 61
13.7.6  Update key . 61

- 3 - 14908-1 © ISO/IEC:2012 (E)
13.7.7  Update address . 62
13.7.8  Query address . 62
13.7.9  Query network variable configuration . 62
13.7.10 Update group address . 62
13.7.11 Query domain . 62
13.7.12 Update network variable configuration . 62
13.7.13 Set node mode . 63
13.7.14 Read memory . 63
13.7.15 Write memory . 63
13.7.16 Checksum recalculate. 63
13.7.17 Install . 64
13.7.18 Memory refresh . 78
13.7.19 Query SI . 78
13.7.20 Network variable value fetch . 79
13.7.21 Manual service request message . 79
13.7.22 Network management escape code . 79
13.7.23 Router mode . 80
13.7.24 Router clear group or subnet table . 80
13.7.25 Router group or subnet table download . 80
13.7.26 Router group forward . 80
13.7.27 Router subnet forward . 80
13.7.28 Router Do Not forward group . 80
13.7.29 Router Do Not forward subnet . 80
13.7.30 Router group or subnet table report . 80
13.7.31 Router status . 81
13.7.32 Router half escape code . 81
13.8  DPDU types and formats . 81
13.8.1  General . 81
13.8.2  Query status . 81
13.8.3  Proxy status . 85
13.8.4  Clear status . 85
13.8.5  Query transceiver status . 85
Annex A (normative) Reference implementation . 86
A.1  General . 86
A.2  Predictive CSMA algorithm . 86
A.3  LPDU transmit algorithm .141
A.4  LPDU receive algorithm .143
A.5  Routing algorithm .144
A.6  Learning algorithm .145
A.7  Transaction control algorithm .145
A.8  Network layer algorithm.152
A.9  TPDU and SPDU send algorithm with authentication .168
A.10  Application Layer .223
A.11  Network Management Commands .278
A.12  Configuration data structures .315
A.13  Include files for the reference implementation .334
A.14  Application protocol state variables and address recognition Structures .363
A.15  Query-id data structures .366
A.16  Respond to query data structure .366
A.17  Update somain data structures .367
A.18  Leave domain data structures .367
A.19  Update key data structures .367
A.20  Update address data structures .367
A.21  Query address data structures .368
A.22  Query NV Cnfg data structures .369
A.23  Update group address data structures .369
A.24  Query domain data structures .369
A.25  Update network variable configuration data structures .370
A.26  Set node mode data structures .370

14908-1 © ISO/IEC:2012 (E) - 4 -
A.27  Read memory data structures .370
A.28  Write memory data structures .371
A.29  Checksum recalculate data structures .371
A.30  Install command data structures .371
A.31  Memory refresh data structures .380
A.32  Query SI data structures .380
A.33  NV fetch data structures .380
A.34  Manual service request message ddata structures .380
A.35  Product query data structures .381
A.36  Router mode data structures .381
A.37  Router table clear group or subnet table data structures .381
A.38  Router group or subnet download data structures .381
A.39  Router group forward data structures .382
A.40  Router subnet forward data structures .382
A.41  Router group No-Forward data structures .382
A.42  Router subnet No-Forward data structures .382
A.43  Group / subnet table report data structures .383
A.44  Router status data structures .383
A.45  Query status data structures .383
A.46  Proxy status data structures .384
A.47  Clear status data structures .384
A.48  Query transceiver status data structures .384
Annex B (normative) Additional Data Structures .385
B.1  General .385
B.1.1  System image .385
B.1.2  Application image .385
B.1.3  Network image .386
B.2  Read-only structures .386
B.2.1  Fixed read-only data structures .386
B.2.2  Read-only structure field descriptions .387
B.3  Domain table .390
B.3.1  Domain table field descriptions .391
B.4  Address table .391
B.4.1  Declaration of group address format .392
B.4.2  Group address field descriptions .392
B.4.3  Declaration of subnet/node address format .392
B.4.4  Subnet/node address field descriptions .393
B.4.5  Declaration of broadcast address format .393
B.4.6  Broadcast address field descriptions .393
B.4.7  Declaration of turnaround address format .393
B.4.8  Turnaround address field descriptions .394
B.4.9  Declaration of protocol processor’s address format .394
B.4.10  Protocol processor address field descriptions .394
B.4.11  Timer field descriptions .394
B.5  Network variable tables - informative .395
B.5.1  Network variable configuration table field descriptions - informative .396
B.5.2  Network variable alias table field descriptions - informative.397
B.5.3  Network variable fixed table field descriptions - informative .397
B.6  Self-Identification structures .397
B.6.1  SI Structure field descriptions .398
B.6.2  NV descriptor table field descriptions .398
B.6.3  SNVT table extension records .399
B.6.4  SNVT alias field descriptions .400
B.6.5  Version 2 SI data .400
B.7  Configuration structure .403
B.7.1  General .403
B.7.2  Configuration structure field descriptions .404
B.8  Statistics relative structure .405
Annex C (informative) Behavioral characteristics .407

- 5 - 14908-1 © ISO/IEC:2012 (E)
C.1  Channel capacity and throughput .407
C.2 Network metrics .408
C.3 Transaction metrics .409
C.4 Boundary conditions — power-up .410
C.5 Boundary conditions — high load .410
Annex D (normative) PDU summary .411
Annex E (normative) Naming and addressing .413
E.1  Address types and formats .413
E.2  Domains .413
E.3  Subnets and nodes .414
E.4  Groups .414
E.5  Unique_Node_ID and node address assignment .415
E.6  NPDU addressing .416
Annex F (normative) List of patents that pertain to this International Standard .418
Bibliography .420

Figures
Figure 1 — Network topology & symbols . 12
Figure 2 — Protocol terminology . 12
Figure 3 — Protocol layering . 14
Figure 4 — Interface between the MAC and the link layers . 16
Figure 5 — MPDU/LPDU format . 17
Figure 6 — Predictive p-persistent CSMA concepts and parameters . 18
Figure 7 — Allocation of priority slots within the Busy Channel Packet Cycle . 20
Figure 8 — CRC register state behaviour example . 25
Figure 9 — Single channel topologies . 26
Figure 10 — Typical tree-like domain topology . 27
Figure 11 — Network service interface . 28
Figure 12 — Network layer—internal structure . 28
Figure 13 — NPDU format . 28
Figure 14 — Transaction control service interface . 31
Figure 15 — Transport interface to upper layers. 33
Figure 16 — TPDU types and formats . 34
Figure 17 — Transport protocol diagram for multicast message with a loss of both the message and
the ACK TPDUs . 35
Figure 18 — Transport protocol—Send FSM . 36
Figure 19 — Transport protocol—Receive FSM . 36
Figure 20 — Probability of transaction completion in k Retries . 37

14908-1 © ISO/IEC:2012 (E) - 6 -
Figure 21 — Methodology for calculating timer values . 38
Figure 22 — Session layer interface to application layer . 39
Figure 23 — Session layer—internal structuring . 40
Figure 24 — SPDU types and formats . 41
Figure 25 — Non-Idempotent request with multiple SPDU losses . 43
Figure 26 — Secure idempotent request with multiple SPDU losses . 44
Figure 27 — Request-response protocol—client FSM . 45
Figure 28 — Request-response protocol—simplified server FSM . 45
Figure 29 — Application layer interface . 48
Figure 30 — APDU format . 49
Figure 31 — Application protocol diagram for multicast acknowledged transaction . 50
Figure 32 — Application protocol diagram for multicast request/response transaction . 51
Figure B.1 — SI data . 400
Figure C.1 — Probability of successful delivery over k hops 409
Figure D.1 — Protocol PDU summary . 412
Figure E.1 — Physical topology and logical addressing (single domain) . 415
Figure E.2 — NPDU/TPDU/SPDU addressing—physical address formats . 416
Tables
Table 1 — Application layer primitives . 48
Table 2 — Resource codes . 65
Table 3 — Space of the property ID . 65
Table B.1 — Buffer size encodings . 389
Table B.2 — Buffer Count Encodings . 390
Table B.3 — Encoding of timer field values . 395
Table B.4 — Buffer timeout encoding . 405
Table C.1 — Key throughput parameters . 408
Table E.1 — NPDU/TPDU/SPDU addressing - logical address formats . 416
Table F.1 — Patents in the US . 418
Table F.2 — Patents in Europe and other countries . 419

- 7 - 14908-1 © ISO/IEC:2012 (E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical activity.
ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work. In the field of information technology, ISO and IEC have established a joint technical committee,
ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the national bodies
casting a vote.
ISO/IEC 14908-1 was prepared by CEN/TC 247 and was adopted, under a special “fast-track
procedure”, by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel with its
approval by the national bodies of ISO and IEC.
ISO/IEC 14908 consists of the following parts, under the general title Information technology —
Control network protocol:
 Part 1: Protocol stack
 Part 2: Twisted pair communication
 Part 3: Power line channel specification
 Part 4: IP communication
14908-1 © ISO/IEC:2012 (E) - 8 -
Introduction
This International Standard has been prepared to provide mechanisms through which various vendors
of local area control networks may exchange information in a standardised way. It defines
communication capabilities.
This International Standard is to be used by all involved in design, manufacture, engineering,
installation and commissioning activities.
The International Organization for Standardization (ISO) and International Electrotechnical
Commission (IEC) draw attention to the fact that it is claimed that compliance with this International
Standard may involve the use of patents held by Echelon Corporation.
The ISO and IEC take no position concerning the evidence, validity and scope of this patent right. The
holder of this putative patent right has assured the ISO and IEC that they are willing to negotiate free
of charge licences under reasonable and non-discriminatory terms and conditions with applicants
throughout the world. In this respect, the statement of the holder of the putative patent rights is registered
with the ISO and IEC. Information may be obtained from:
Echelon Corporation, 4015 Meridian Avenue, San Jose, CA 94304, USA, phone +1-408-938-
5234, fax: +1-408-790-3800 http://www.echelon.com.
Attention is drawn to the possibility that some of the elements of this International Standard may be
the subject of patent rights other than those identified above. ISO and IEC shall not be held
responsible for identifying any or all such patent rights.

- 9 - 14908-1 © ISO/IEC:2012 (E)
INFORMATION TECHNOLOGY –
CONTROL NETWORK PROTOCOL –
Part 1: Protocol stack
1 Scope
This specification applies to a communication protocol for local area control networks. The protocol
provides peer-to-peer communication for networked control and is suitable for implementing both peer-
to-peer and master-slave control strategies. This specification describes services in layers 2 to 7. In
the layer 2 (data link layer) specification, it also describes the MAC sub-layer interface to the physical
layer. The physical layer provides a choice of transmission media. The interface described in this
specification supports multiple transmission media at the physical layer. In the layer 7 specification, it
includes a description of t
...