ISO 21806-2:2020
(Main)Road vehicles — Media Oriented Systems Transport (MOST) — Part 2: Application layer
Road vehicles — Media Oriented Systems Transport (MOST) — Part 2: Application layer
This document specifies a part of the application, the application layer, and the presentation layer. The application covers the — device model, — registry management, — connection management for streaming data, — diagnosis, and — error handling. The application layer covers the structure of MOST messages consisting of — addressing, — function block identifiers, — instance identifiers, — function identifiers, — operation types, and — timing definitions. The presentation layer covers the definition of data, basic data types and function classes.
Véhicules routiers — Système de transport axé sur les médias — Partie 2: Couche d’application
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 21806-2
First edition
2020-09
Road vehicles — Media Oriented
Systems Transport (MOST) —
Part 2:
Application layer
Véhicules routiers — Système de transport axé sur les médias —
Partie 2: Couche d’application
Reference number
ISO 21806-2:2020(E)
©
ISO 2020
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ISO 21806-2:2020(E)
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ISO 21806-2:2020(E)
Contents Page
Foreword .vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
4.1 Symbols . 3
4.2 Abbreviated terms . 3
5 Conventions . 4
6 APP — Application . 4
6.1 APP — Device model . 4
6.2 APP — Node kinds . 5
6.2.1 APP — MOST nodes . 5
6.2.2 APP — Remote-controlled nodes . 6
6.2.3 APP — Listen-only nodes . 6
6.3 APP — Function block . 6
6.3.1 APP — General . 6
6.3.2 APP — FBlock library . 7
6.3.3 APP — Controller and FBlock . 7
6.4 APP — Functions. 8
6.4.1 APP — Overview . 8
6.4.2 APP — Methods . 9
6.4.3 APP — Properties .11
6.5 APP — Events and notification .12
6.5.1 APP — Events .12
6.5.2 APP — Notification .12
6.6 APP — Notification mechanisms.13
6.6.1 APP — General .13
6.6.2 APP — Notification function.14
6.6.3 APP — Implicit notification .15
6.6.4 APP — Automatic notification .15
6.6.5 APP — Errors in the context of the notification function .15
6.6.6 APP — No valid values or property failure .15
6.6.7 APP — Reactions on Configuration.Status events .16
6.7 APP — Requesting FBlock information .16
6.7.1 APP — Function FBlockIDs .16
6.7.2 APP — Function FktIDs.17
6.7.3 APP — Extended FBlock identification .17
6.8 APP — Registry management .18
6.8.1 APP — General .18
6.8.2 APP — Central registry state .19
6.8.3 APP — NetworkMaster .22
6.8.4 APP — NetworkSlave .33
6.9 APP — Network wake-up, startup, and shutdown .40
6.9.1 APP — General .40
6.9.2 APP — Network wake-up and startup .41
6.9.3 APP — Network shutdown .41
6.9.4 APP — Device shutdown .43
6.10 APP — Connection management for streaming data .45
6.10.1 APP — Service for streaming data.45
6.10.2 APP — Source and sink information .46
6.10.3 APP — Streaming connections .48
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ISO 21806-2:2020(E)
6.10.4 APP — Compensating MOST network delay .54
6.11 APP — Diagnosis .54
6.11.1 APP — FBlock configuration status information .54
6.11.2 APP — Shutdown reason .56
6.11.3 APP — Shutdown reason analysis .56
6.11.4 APP — Ring break diagnosis .57
6.11.5 APP — Network diagnosis .57
6.12 APP — Error handling .58
6.12.1 APP — General .58
6.12.2 APP — Handling overload in a message receiver .58
6.12.3 APP — Over-temperature management .59
6.13 APP — Timing definitions .62
6.13.1 APP — Definitions .62
6.13.2 APP — NetworkMaster communication .62
6.13.3 APP — PowerMaster communication .66
7 AL — Application layer .68
7.1 AL — Structure of MOST messages .68
7.2 AL — Addressing .68
7.2.1 AL — Overview .68
7.2.2 AL — 16-bit addressing .69
7.2.3 AL — 48-bit addressing (Ethernet MAC address) .70
7.3 AL — Function block identifier (FBlockID) .70
7.4 AL — Instance identifier (InstID) .73
7.4.1 AL — Distinction of FBlock instances .73
7.4.2 AL — Uniqueness of functional addresses .73
7.4.3 AL — Assigning InstID .73
7.4.4 AL — InstID of NetBlock FBlock.73
7.4.5 AL — InstID of NetworkMaster FBlock .73
7.4.6 AL — InstID of FBlock EnhancedTestability .73
7.4.7 AL — Wildcard values for InstID .74
7.5 AL — Function identifier (FktID) .75
7.6 AL — Operation type (OPType) .76
7.6.1 AL — Overview .76
7.6.2 AL — Set, Get and SetGet .77
7.6.3 AL — Increment and Decrement .77
7.6.4 AL — Status .78
7.6.5 AL — Start and StartAck .78
7.6.6 AL — StartResult and StartResultAck .78
7.6.7 AL — Result and ResultAck .79
7.6.8 AL — Processing and ProcessingAck .79
7.6.9 AL — Abort and AbortAck .80
7.6.10 AL — Error and ErrorAck .80
7.6.11 AL — Parameters .86
7.7 AL — Timing definitions .87
7.7.1 AL — Definitions .87
7.7.2 AL — General communication .87
8 PL — Presentation layer .90
8.1 PL — Data and basic data types .90
8.1.1 PL — General .90
8.1.2 PL — Boolean .91
8.1.3 PL — Enum .91
8.1.4 PL — Numeric data types .92
8.1.5 PL — Length-coded String .97
8.1.6 PL — Array Type .98
8.1.7 PL — Record Type .99
8.1.8 PL — Stream .100
8.1.9 PL — BitField .103
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ISO 21806-2:2020(E)
8.1.10 PL — String .104
8.1.11 PL — Short Stream .106
8.1.12 PL — Classified Stream .106
8.2 PL — Function classes .107
8.2.1 PL — Purpose .107
8.2.2 PL — Properties with a single parameter .107
8.2.3 PL — Properties with multiple parameters .110
8.2.4 PL — Function classes for methods .134
9 Service interface definition to transport layer and network layer .135
Bibliography .136
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ISO 21806-2:2020(E)
Foreword
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different types of ISO documents should be noted. This document was drafted in accordance with the
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patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
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This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 31,
Data communication.
A list of all parts in the ISO 21806 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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ISO 21806-2:2020(E)
Introduction
The Media Oriented Systems Transport (MOST) communication technology was initially developed at
the end of the 1990s in order to support complex audio applications in cars. The MOST Cooperation was
founded in 1998 with the goal to develop and enable the technology for the automotive industry. Today,
1)
MOST enables the transport of high quality of service (QoS) audio and video together with packet data
and real-time control to support modern automotive multimedia and similar applications. MOST is a
function-oriented communication technology to network a variety of multimedia devices comprising
one or more MOST nodes.
Figure 1 shows a MOST network example.
Figure 1 — MOST network example
The MOST communication technology provides:
— synchronous and isochronous streaming,
— small overhead for administrative communication control,
— a functional and hierarchical system model,
— API standardization through a function block (FBlock) framework,
— free partitioning of functionality to real devices,
— service discovery and notification, and
[7]
— flexibly scalable automotive-ready Ethernet communication according to ISO/IEC/IEEE 8802-3 .
MOST is a synchronous time-division-multiplexing (TDM) network that transports different data types
on separate channels at low latency. MOST supports different bit rates and physical layers. The network
clock is provided with a continuous data signal.
1) MOST® is the registered trademark of Microchip Technology Inc. This information is given for the convenience
of users of this document and does not constitute an endorsement by ISO.
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ISO 21806-2:2020(E)
Within the synchronous base data signal, the content of multiple streaming connections and control
data is transported. For streaming data connections, bandwidth is reserved to avoid interruptions,
collisions, or delays in the transport of the data stream.
MOST specifies mechanisms for sending anisochronous, packet-based data in addition to control data
and streaming data. The transmission of packet-based data is separated from the transmission of
control data and streaming data. None of them interfere with each other.
A MOST network consists of devices that are connected to one common control channel and packet
channel.
In summary, MOST is a network that has mechanisms to transport the various signals and data streams
that occur in multimedia and infotainment systems.
The ISO standards maintenance portal (https:// standards .iso .org/ iso/ ) provides references to MOST
specifications implemented in today's road vehicles because easy access via hyperlinks to these
specifications is necessary. It references documents that are normative or informative for the MOST
versions 4V0, 3V1, 3V0, and 2V5.
The ISO 21806 series has been established in order to specify requirements and recommendations
for implementing the MOST communication technology into multimedia devices and to provide
conformance test plans for implementing related test tools and test procedures.
To achieve this, the ISO 21806 series is based on the open systems interconnection (OSI) basic reference
[3] [5]
model in accordance with ISO/IEC 7498-1 and ISO/IEC 10731 , which structures communication
systems into seven layers as shown in Figure 2. Stream transmission applications use a direct stream
data interface (transparent) to the data link layer.
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ISO 21806-2:2020(E)
Figure 2 — The ISO 21806 series reference according to the OSI model
The International Organization for Standardization (ISO) draws attention to the fact that it is claimed
that compliance with this document may involve the use of a patent.
ISO takes no position concerning the evidence, validity and scope of this patent right.
The holder of this patent right has assured ISO that he/she is willing to negotiate licences under
reasonable and non-discriminatory terms and conditions with applicants throughout the world. In
this respect, the statement of the holder of this patent right is registered with ISO. Information may be
obtained from the patent database available at www .iso .org/ patents.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights other than those in the patent database. ISO shall not be held responsible for identifying
any or all such patent rights.
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INTERNATIONAL STANDARD ISO 21806-2:2020(E)
Road vehicles — Media Oriented Systems Transport
(MOST) —
Part 2:
Application layer
1 Scope
This document specifies a part of the application, the application layer, and the presentation layer.
The application covers the
— device model,
— registry management,
— connection management for streaming data,
— diagnosis, and
— error handling.
The application layer covers the structure of MOST messages consisting of
— addressing,
— function block identifiers,
— instance identifiers,
— function identifiers,
— operation types, and
— timing definitions.
The presentation layer covers the definition of data, basic data types and function classes.
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
...
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