ISO 21806-15:2021

INTERNATIONAL ISO
STANDARD 21806-15
First edition
Road vehicles — Media Oriented
Systems Transport (MOST) —
Part 15:
Lean application layer conformance
test plan
Véhicules routiers — Système de transport axé sur les médias —
Partie 15: Plan d'essais de conformité de la couche d'application
allégée
PROOF/ÉPREUVE
Reference number
ISO 21806-15:2021(E)
©
ISO 2021

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ISO 21806-15:2021(E)

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Published in Switzerland
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ISO 21806-15:2021(E)

Contents Page
Foreword .iv
Introduction .v
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 Conformance test plan (CTP) overview . 2
6.1 Test set-up . 2
6.2 Conformance test plan organization . 3
7 Conformance test plan (CTP) general information . 3
7.1 Timer naming . 3
7.2 Deadlock prevention . 4
7.3 Addresses of nodes in the lower tester . 4
7.4 Device manufacturer information list . 4
7.5 States of the node that contains the IUT . 4
7.6 Violation of prerequisites of the CTC . 5
8 CTC specification for root nodes . 5
8.1 CTC_15.1-1 – Network startup test for root node . 5
8.2 CTC_15.2-1 – Network shutdown test for root node . 5
8.3 CTC_15.3-1 – Unlock robustness test for root node . 6
8.4 CTC_15.4-1 – Critical unlock test for root node . 6
8.5 CTC_15.5-1 – SSO test for root node . 7
8.6 CTC_15.6-1 – Valid signature test for root node . 8
8.7 CTC_15.7-1 – Unknown signature test for root node . 9
8.8 CTC_15.8-1 – NCE test for root node . 9
8.9 CTC_15.9-1 – Timer t test for root node .10
Hello
8.10 CTC_15.10-1 – Duplicate signature test for root node .11
8.11 CTC_15.11-1 – Remote node reset test for root node .11
8.12 CTC_15.12-1 – Connection management test for root node .12
8.13 CTC_15.13-1 – Welcome_Error reaction test for root node .13
9 CTC specification for remote nodes .14
9.1 CTC_15.1-2 – Network startup test for remote node .14
9.2 CTC_15.2-2 – Network shutdown test for remote node .14
9.3 CTC_15.3-2 – Unlock robustness test for remote node .15
9.4 CTC_15.4-2 – Critical unlock test for remote node.15
9.5 CTC_15.5-2 – SSO test for remote node .16
9.6 CTC_15.6-2 – Valid signature test for remote node .16
9.7 CTC_15.7-2 – Hello_Get ignore test for remote node .17
9.8 CTC_15.8-2 – Unchanged node position address test for remote node .18
Bibliography .19
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ISO 21806-15:2021(E)

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 trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
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
complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO 21806-15:2021(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
[2]
— 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.
MOST® is the registered trademark of Microchip Technology Inc. This information is given for the convenience of users of this document and does
1)
not constitute an endorsement by ISO.
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ISO 21806-15:2021(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
[1] [3]
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 21806-15:2021(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 21806-15:2021(E)
Road vehicles — Media Oriented Systems Transport
(MOST) —
Part 15:
Lean application layer conformance test plan
1 Scope
This document specifies the conformance test plan (CTP) for the lean application layer for MOST, a
synchronous time-division-multiplexing network, as specified in ISO 21806-14.
This document specifies conformance test cases (CTCs) for root nodes and remote nodes in the following
categories:
— network startup;
— network shutdown;
— network events;
— node discovery;
— connection management.
Interoperability testing is not in the scope of this document.
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 the referenced document (including any amendments) applies.
ISO 21806-1, Road vehicles — Media Oriented Systems Transport (MOST) — Part 1: General information
and definitions
ISO 21806-4, Road vehicles — Media Oriented Systems Transport (MOST) — Part 4: Transport layer and
network layer
ISO 21806-14:2021, Road vehicles — Media Oriented Systems Transport (MOST) — Part 14: Lean
application layer
ISO/IEC 9646-1, Information technology — Open Systems Interconnection — Conformance testing
methodology and framework — Part 1: General concepts
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21806-1, ISO 21806-4,
ISO 21806-14, ISO/IEC 9646-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
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4 Symbols and abbreviated terms
4.1 Symbols
--- empty table cell or feature undefined
4.2 Abbreviated terms
CTC conformance test case
CTP conformance test plan
IUT implementation under test
LT lower tester
NCE network change event
OSI Open Systems Interconnection
UT upper tester
5 Conventions
[3]
This document is based on OSI service conventions as specified in ISO/IEC 10731 and ISO/IEC 9646-1
for conformance test system set-up.
6 Conformance test plan (CTP) overview
6.1 Test set-up
All CTCs are based on the same test set-up with an upper tester (UT) and a lower tester (LT). The LT
contains the lower tester pre-IUT (LT pre-IUT) and the lower tester post-IUT (LT post-IUT).
Figure 3 shows the test set-up.
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Figure 3 — Test set-up
The UT can configure the LT pre-IUT as root node or remote node. The UT can configure the LT post-
IUT as root node or remote node or disconnect the corresponding interface. The LT post-IUT contains a
listen-only node to monitor the network status, communication and streaming. The root node operates
as TimingMaster. A remote node operates as TimingSlave.
The UT is able to provide the remote nodes in the LT pre-IUT and the LT post-IUT with a signature.
Every CTC contains a description of the experimental set-up that specifies the roles of the LT pre-IUT
and the LT post-IUT.
During testing of the MOST device that implements the IUT, avoid over-temperature by following the
manufacturer recommendations regarding cooling.
6.2 Conformance test plan organization
The CTCs are independent of one another. Each CTC checks the behaviour of the IUT for requirements
stated in ISO 21806-14.
7 Conformance test plan (CTP) general information
7.1 Timer naming
For conformance testing of the IUT, the UT and LT need minimum and maximum timers. The names of
the timers used by this document are based on ISO 21806-14. To obtain the timer name, for minimum
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and maximum, “ ” and “ ” are appended, respectively. Table 1 shows a timer naming definition
_min _max
example for t .
Hello
Table 1 — Timer naming example
Name Minimum Typical Maximum Unit Purpose
value name value name value name
t t t t ms Cycle time for Hello_Get broadcasts by the
Hello Hello_min Hello Hello_max
lean network services.
7.2 Deadlock prevention
This document specifies the timeouts t , t , and t to prevent deadlock
DeadLockShort DeadLockMid DeadLockLong
situations during conformance testing. These are the default values:
— t : 1 s;
DeadLockShort
— t : 20 s;
DeadLockMid
— t : 5 min.
DeadLockLong
These timeouts are only relevant for conformance testing and may be extended.
7.3 Addresses of nodes in the lower tester
By default, the LT shall use the un-initialised logical node address as specified in ISO 21806-14:2021,
Clause 8.
7.4 Device manufacturer information list
The device manufacturer list contains:
— the signature,
— the network descriptor (if the IUT is a root node),
— the network startup trigger (if the IUT is a root node),
— timer t , and
Hello
— timer t .
RD
There are parameters that can be provided by proprietary extensions to the network descriptor and
the order might differ between manufacturers. Therefore, complete commands should be provided, in
the order they are transported on the network.
7.5 States of the node that contains the IUT
Table 2 specifies how the NetInterface state s_NetInterface_Normal_Operation is effectuated and
detected in the node that contains the IUT.
Table 2 — Effectuate and detect s_NetInterface_Normal_Operation
Effectuate state Detect state
If the LT contains the root node, it shall switch on the MOST output. Lock flag
If the LT does not contain the root node, the UT shall provide the IUT
with a network startup trigger.
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Table 3 specifies how the NetInterface state s_NetInterface_Off is effectuated and detected in the
node that contains the IUT.
Table 3 — Effectuate and detect s_NetInterface_Off
Effectuate state Detect state
The LT shall switch off the MOST output. No network activity
7.6 Violation of prerequisites of the CTC
If the node that contains the IUT does not meet the prerequisites of the CTC (such as network activity or
lock), the CTC results in "IUT not ok: the IUT does not meet the prerequisites".
8 CTC specification for root nodes
8.1 CTC_15.1-1 – Network startup test for root node
Table 4 specifies the CTC_15.1-1 – Network startup test for root node.
Table 4 — CTC_15.1-1 — Network startup test for root node
Item Content
CTC # – Title CTC_15.1-1 – Network startup test for root node
Purpose This CTC verifies that the root node is able to perform a network startup.
This CTC applies to all MOST devices that contain the root node.
Reference ISO 21806-14:2021:
— 11.2.1;
— 13.1: REQ 7.22 AL – Lean network services perform startup and shutdown.
Prerequisite ---
Set-up — The LT pre-IUT shall be a remote node.
— The LT post-IUT shall be a listen-only node.
Step 1. The UT shall trigger a wake-up event in the IUT.
2. The UT shall determine the presence of network activity, using the LT post-IUT.
Iteration Not applicable
Expected re- Step 2: IUT ok: the IUT performs a network startup.
sponse
Step 2: IUT not ok: the IUT does not perform a network startup.
Remark ---
8.2 CTC_15.2-1 – Network shutdown test for root node
Table 5 specifies the CTC_15.2-1 – Network shutdown test for root node.
Table 5 — CTC_15.2-1 — Network shutdown test for root node
Item Content
CTC # – Title CTC_15.2-1 – Network shutdown test for root node
Purpose This CTC verifies that the root node is able to perform a network shutdown.
This CTC applies to all MOST devices that contain the root node.
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Table 5 (continued)
Item Content
Reference ISO 21806-14:2021:
— 11.2.1;
— 13.1: REQ 7.22 AL – Lean network services performs startup and shutdown.
Prerequisite The UT shall effectuate s_NetInterface_Normal_Operation in the IUT.
Set-up — The LT pre-IUT shall be a remote node.
— The LT post-IUT shall be a listen-only node.
Step 1. The UT shall trigger a network shutdown in the IUT.
2. The UT shall determine the presence of the shutdown flag, using the LT post-IUT.
3. The UT shall determine the disappearance of network activity, using the LT post-IUT.
Iteration Not applicable
Expected Step 3: IUT ok: the IUT performs a network shutdown.
response
Step 3: IUT not ok (1): the IUT does not perform a network shutdown.
Step 2: IUT not ok (2): the IUT does not set the shutdown flag.
Remark ---
8.3 CTC_15.3-1 – Unlock robustness test for root node
Table 6 specifies the CTC_15.3-1 – Unlock robustness test for root node.
Table 6 — CTC_15.3-1 — Unlock robustness test for root node
Content Content
CTC # – Title CTC_15.3-1 – Unlock robustness test for root node
Purpose This CTC verifies that the root node remains in
s_NetInterface_Normal_Operation during a series of unlocks without critical unlock, see
[4]
ISO 21806-6 .
This CTC applies to all MOST devices that contain the root node.
Reference ISO 21806-14:2021, 13.2.3
Prerequisite The UT shall effectuate s_NetInterface_Normal_Operation in the IUT.
Set-up — The LT pre-IUT shall be a remote node.
— The LT post-IUT shall be a listen-only node.
Step 1. The UT shall generate a series of unlocks without critical unlock, using the LT pre-IUT.
2. The UT shall determine the presence of network activity, using the LT post-IUT.
Iteration Not applicable
Expected re- Step 2: IUT ok: the IUT remains in s_NetInterface_Normal_Operation.
sponse
Step 2: IUT not ok: the IUT switches off the MOST output.
Remark ---
8.4 CTC_15.4-1 – Critical unlock test for root node
Table 7 specifies the CTC_15.4-1 – Critical unlock test for root node.
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Table 7 — CTC_15.4-1 — Critical unlock test for root node
Item Content
CTC # – Title CTC_15.4-1 – Critical unlock test for root node
Purpose This CTC verifies that the root node reacts to a critical unlock by shutting down the network.
This CTC applies to all MOST devices that contain the root node.
Reference ISO 21806-14:2021, 13.2.3
Prerequisite The UT shall effectuate s_NetInterface_Normal_Operation in the IUT.
Set-up — The LT pre-IUT shall be a remote node.
— The LT post-IUT shall be a listen-only node.
Step 1. The UT shall generate a critical unlock, using the LT pre-IUT.
2. The UT shall determine the presence of the shutdown flag, using the LT post-IUT.
3. The UT shall determine the disappearance of network activity, using the LT post-IUT.
4. The UT, using the LT post-IUT, shall determine whether a startup attempt is made.
Iteration Not applicable
Expected re- Step 3: IUT ok: the IUT sets the shutdown flag and switches off the MOST output.
sponse
Step 3: IUT not ok (1): the IUT does not switch off the MOST output.
Step 3: IUT not ok (2): the IUT switches off the MOST output without setting the shutdown flag.
Step 4: IUT not ok (3): the IUT does not attempt to restart the network.
Remark ---
8.5 CTC_15.5-1 – SSO test for root node
Table 8 specifies the CTC_15.5-1 – SSO test for root node.
Table 8 — CTC_15.5-1 — SSO test for root node
Item Content
CTC # – Title CTC_15.5-1 – SSO test for root node
Purpose This CTC verifies that the root node reacts to an SSO.
This CTC applies to all MOST devices that contain the root node.
Reference ISO 21806-14:2021:
— 13.2.2;
— 13.2.2: REQ 7.26 AL – Root node reacts on SSO.
Prerequisite The UT shall effectuate s_NetInterface_Normal_Operation in the IUT.
Set-up — The LT pre-IUT shall be a remote node.
— The LT post-IUT shall be a listen-only node.
Step 1. The UT shall generate an SSO, using the LT pre-IUT.
2. The UT shall determine the presence of the shutdown flag, using the LT post-IUT.
3. The UT shall determine the disappearance of network activity, using the LT post-IUT.
4. The UT, using the LT post-IUT, shall determine whether a startup attempt is made.
Iteration Not applicable
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Table 8 (continued)
Item Content
Expected re- Step 4: IUT ok: the IUT sets the shutdown flag, switches off the MOST output, and performs a
sponse startup attempt.
Step 3: IUT not ok (1): the IUT does not switch off the MOST output.
Step 3: IUT not ok (2): the IUT switches off the MOST output without setting the shutdown flag.
Step 4: IUT not ok (3): the IUT does not attempt to restart the network.
Remark ---
8.6 CTC_15.6-1 – Valid signature test for root node
Table 9 specifies the CTC_15.6-1 – Valid signature test for root node.
Table 9 — CTC_15.6-1 — Valid signature test for root node
Item Content
CTC # – Title CTC_15.6-1 – Valid signature test for root node
Purpose This CTC verifies that the root node responds with Welcome_StartResult after receiving a
valid signature in Hello_Status.
This CTC applies to all MOST devices that contain the root node.
Reference ISO 21806-14:2021:
— 13.3.3;
— 13.3.3: REQ 7.38 AL – Lean network services send Init_Start;
— 13.3.3: REQ 7.39 AL – Lean network services broadcast Hello_Get.
Prerequisite The UT shall effectuate s_NetInterface_Normal_Operation in the IUT.
Set-up — The LT pre-IUT shall be a remote node.
— The LT post-IUT shall be a listen-only node.
Step 1. The UT, using the LT post-IUT, shall wait for Init_Start sent to the blocking broadcast
address.
2. The UT, using the LT post-IUT, shall wait for Hello_Get sent to the blocking broadcast
address.
3. The UT shall verify that the source address of the Hello_Get
...