ISO 21806-4:2020

INTERNATIONAL ISO
STANDARD 21806-4
First edition
2020-09
Road vehicles — Media Oriented
Systems Transport (MOST) —
Part 4:
Transport layer and network layer
Véhicules routiers — Système de transport axé sur les médias —
Partie 4: Couche de transport et couche réseau
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
4.1 Symbols . 2
4.2 Abbreviated terms . 2
5 Conventions . 2
6 Transport layer service interface to upper OSI layers . 3
6.1 Overview of services . 3
6.2 Data type definitions . 3
6.3 Parameters . 4
6.3.1 Parameters — NL/TL to upper layers . 4
6.3.2 Parameters — Upper layers to TL/NL . 7
6.3.3 Parameters – NL/TL to upper layers and upper layers to TL/NL .10
6.4 Event indications and action requests .12
6.4.1 N_EVENT.INDICATE .12
6.4.2 N_NODE_POSITION.INDICATE .12
6.4.3 N_MAXIMUM_NODE_POSITION.INDICATE .12
6.4.4 N_NET_INTERFACE_TRANSITION.INDICATE .12
6.4.5 N_DIAGRESULT.INDICATE .13
6.4.6 N_SHUTDOWN_REASON.INDICATE .13
6.4.7 N_ACTION.REQUEST .13
6.4.8 N_NETWORK_STARTUP.REQUEST .13
6.4.9 N_SET_GROUP_ADDRESS.REQUEST .14
6.4.10 N_SET_NODE_ADDRESS.REQUEST .14
6.4.11 N_SET_EUI_48.REQUEST .14
6.5 Control data .14
6.5.1 N_CONTROL_DATA.RECEIVE .14
6.5.2 N_CONTROL_DATA.CONFIRM .15
6.5.3 N_SET_MESSAGE_ATTRIBUTES.REQUEST .15
6.5.4 N_CONTROL_DATA.SEND .15
6.6 Packet data .15
6.6.1 16-bit addressing.15
6.6.2 48-bit addressing.16
6.7 Streaming data .16
6.7.1 N_ALLOCATE.INDICATE.16
6.7.2 N_DEALLOCATE.INDICATE .17
6.7.3 N_CONNECT.INDICATE .17
6.7.4 N_DISCONNECT.INDICATE .17
6.7.5 N_SOURCE_DROP.INDICATE .17
6.7.6 N_STREAMING_DATA.RECEIVE .18
6.7.7 N_ALLOCATE.REQUEST .18
6.7.8 N_DEALLOCATE.REQUEST .18
6.7.9 N_CONNECT.REQUEST .18
6.7.10 N_DISCONNECT.REQUEST .19
6.7.11 N_STREAMING_DATA.SEND.19
7 TL — Transport layer .19
7.1 TL — Overview .19
7.2 TL — Data transport mechanism .19
7.2.1 TL — Transport service .19
7.2.2 TL — Service for control data .19
7.2.3 TL — Service for source data .24
8 NL — Network layer.25
8.1 NL — Overview.25
8.2 NL — Services .25
8.2.1 NL — States and state transitions .25
8.2.2 NL — Network error detection and management .34
8.3 NL — Timing .39
8.3.1 NL — General .39
8.3.2 NL — Timers .39
8.3.3 NL — Timing constraints .39
8.3.4 NL — Network startup and changes .40
8.3.5 NL — Network shutdown .43
8.3.6 NL — General communication .46
8.4 NL — Data link layer service interface .46
Annex A (informative) Ring break diagnosis (RBD) .47
Bibliography .56
iv © ISO 2020 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any
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