ISO 21806-6:2020

Road vehicles — Media Oriented Systems Transport (MOST) — Part 6: Data link layer

This document specifies technical requirements related to the MOST data link layer functionality. A MOST network is comprised of two or more nodes connected through a physical layer. The data link layer functionality is provided by each node. On each network, all nodes are synchronised and one node provides the system clock. This node is the TimingMaster, while all other nodes are TimingSlaves. The timing configuration of the node (TimingMaster or TimingSlave) determines the tasks that need to be performed on the data link layer. The data link layer specifies the following subjects: — the service interface to the network layer; — the network frame, its areas and indicators; — the different network channels; — the different flow control mechanisms; — the load-adaptive arbitration and the round-robin arbitration; — the different addressing options; — the different cyclic redundancy checks, their usage and the CRC acknowledge; — the frame indicators.

Véhicules routiers — Système de transport axé sur les médias — Partie 6: Couche de liaison de données

General Information

• Status: Published
• Publication Date: 17-Sep-2020
• ICS: 43.040.15 - Car informatics. On board computer systems
• Technical Committee: ISO/TC 22/SC 31 - Data communication
• Drafting Committee: ISO/TC 22/SC 31/WG 3 - In-vehicle networks
• Current Stage: 9020 - International Standard under periodical review
• Start Date: 15-Jul-2025
• Completion Date: 15-Jul-2025

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 21806-6
First edition
2020-09
Road vehicles — Media Oriented
Systems Transport (MOST) —
Part 6:
Data link layer
Véhicules routiers — Système de transport axé sur les médias —
Partie 6: Couche de liaison de données
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ii © ISO 2020 – All rights reserved

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 DLL — Service interface to upper layers . 4
6.1 DLL — Overview . 4
6.2 DLL — Data type definitions . 4
6.3 DLL — Parameters . . 5
6.3.1 DLL — Parameters – DLL to TL/NL . 5
6.3.2 DLL — Parameters – TL/NL to DLL . 6
6.3.3 DLL — Parameters – DLL to TL/NL and TL/NL to DLL . 8
6.4 DLL — Event indications and action requests .10
6.4.1 DLL — L_EVENT.INDICATE .10
6.4.2 DLL — L_NODE_POSITION.INDICATE .10
6.4.3 DLL — L_MAXIMUM_NODE_POSITION.INDICATE .10
6.4.4 DLL — L_ACTION.REQUEST .10
6.4.5 DLL — L_NETWORK_STARTUP.REQUEST .11
6.4.6 DLL — L_SET_GROUP_ADDRESS.REQUEST .11
6.4.7 DLL — L_SET_NODE_ADDRESS.REQUEST .11
6.4.8 DLL — L_SET_EUI_48.REQUEST .11
6.4.9 DLL — L_SET_TRANSMISSION_ATTRIBUTES.REQUEST.12
6.5 DLL — Control Data .12
6.5.1 DLL — L_CONTROL_DATA.RECEIVE .12
6.5.2 DLL — L_CONTROL_DATA.CONFIRM .12
6.5.3 DLL — L_CONTROL_DATA.SEND .13
6.6 DLL — Packet data .13
6.6.1 DLL — 16-bit addressing .13
6.6.2 DLL — 48-bit addressing .14
6.7 DLL — Streaming data .15
6.7.1 DLL — L_ALLOCATE.INDICATE .15
6.7.2 DLL — L_DEALLOCATE.INDICATE .15
6.7.3 DLL — L_CONNECT.INDICATE .16
6.7.4 DLL — L_DISCONNECT.INDICATE .16
6.7.5 DLL — L_SOURCE_DROP.INDICATE .16
6.7.6 DLL — L_STREAMING_DATA.RECEIVE .17
6.7.7 DLL — L_ALLOCATE.REQUEST .17
6.7.8 DLL — L_DEALLOCATE.REQUEST .17
6.7.9 DLL — L_CONNECT.REQUEST .18
6.7.10 DLL — L_DISCONNECT.REQUEST .18
6.7.11 DLL — L_STREAMING_DATA.SEND .18
7 DLL — Network frame .18
7.1 DLL — General .18
7.2 DLL — Administrative area .20
7.3 DLL — Source data area .20
7.4 DLL — Indicators .21
8 DLL — Channels .21
8.1 DLL — Allocation channel .21
8.1.1 DLL — General .21
8.1.2 DLL — Allocation frame structure .21
8.1.3 DLL — Common allocation channel related subjects .23
8.1.4 DLL — Allocation channel related subjects for the TimingMaster .24
8.1.5 DLL — Allocation channel related subjects for a TimingSlave .25
8.1.6 DLL — De-allocating . .27
8.1.7 DLL — Source-drop recognition .27
8.1.8 DLL — Error handling .28
8.2 DLL — Control channel .30
8.2.1 DLL — General .30
8.2.2 DLL — Control frame structure .31
8.3 DLL — Protected system channel .31
8.3.1 DLL — General .31
8.3.2 DLL — Protected system frame structure .32
8.4 DLL — Timestamp channel .34
8.4.1 DLL — General .34
8.4.2 DLL — Timestamp frame structure .34
8.4.3 DLL — Behaviour .35
8.5 DLL — Packet channel .35
8.5.1 DLL — General .35
8.5.2 DLL — Packet frame structure .36
8.5.3 DLL — Ethernet data frame structure .37
8.5.4 DLL — Short packet frame or short Ethernet data frame .38
8.6 DLL — Synchronous channel .38
8.6.1 DLL — General .38
8.6.2 DLL — Synchronous frame structure .38
8.7 DLL — Isochronous channel .38
8.7.1 DLL — General .38
8.7.2 DLL — Isochronous frame structure .38
8.8 DLL — Channel
...