ISO/TS 20026:2017

TECHNICAL ISO/TS
SPECIFICATION 20026
First edition
2017-05
Intelligent transport systems —
Cooperative ITS — Test architecture
Systèmes intelligents de transport — SIT coopératifs —
Architecture d’essai
Reference number
ISO/TS 20026:2017(E)
©
ISO 2017

---------------------- Page: 1 ----------------------
ISO/TS 20026:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/TS 20026:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 1
5 Conventions . 2
6 Test system architecture . 2
6.1 General . 2
6.2 IICP test system architecture without test CI . 4
6.3 IICP test system architecture with test CI . 5
6.4 IICP reference architecture . 5
7 IICP usage for conformance testing . 7
7.1 General . 7
7.2 IUT in an ITS-S communications layer . 7
7.2.1 ITS-S access layer. 7
7.2.2 ITS-S networking and transport layer . 8
7.2.3 ITS-S facilities layer . 9
7.3 IUT in the ITS-S management entity .10
7.4 IUT in the ITS-S security entity .10
8 Setting to test mode .11
9 Message types and formats .14
9.1 Unaligned PER .14
9.2 utPort .14
9.3 ltPort .15
9.4 cnPort .15
9.5 IICP management .16
10 Dispatcher .17
Annex A (normative) IICP conformance test .19
Annex B (informative) Binary presentation of test message .22
Bibliography .26
© ISO 2017 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO/TS 20026:2017(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 on 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 the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 204, Intelligent transport systems.
iv © ISO 2017 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/TS 20026:2017(E)

Introduction
For conformance testing in C-ITS, ETSI developed a generic initial test architecture, published in
Reference [6]. Considering the ITS station and communication architecture for C-ITS specified in
ISO 21217 and implementations of ITS station units being compliant with the ITS-S station-internal
management communications protocol (IICP) specified in ISO 24102-4, conformance testing can
be simplified and related effort and cost can be reduced by applying the extended test architecture
specified in this document. IICP enables remote access to all points of control and observation (PCO)
of the implementation under test (IUT) without the need to implement IUT-specific upper tester
applications and lower tester access.
Understanding of this document requires knowledge of:
— the ITS station and communication architecture specified in ISO 21217,
— the IICP specified in ISO 24102-4, and
— the related MX-SAP service primitive functions specified in ISO 24102-3.
Further knowledge of standards related to conformance testing with TTCN-3 is also recommended, for
example:
— Reference [6] on the framework on C-ITS conformance testing, and
— Reference [7] on the TTCN-3 core language.
© ISO 2017 – All rights reserved v

---------------------- Page: 5 ----------------------
TECHNICAL SPECIFICATION ISO/TS 20026:2017(E)
Intelligent transport systems — Cooperative ITS — Test
architecture
1 Scope
This document specifies an extension of the ETSI C-ITS test architecture for conformance testing of
protocols and applications in ITS station units. It specifies usage of the ITS station-internal management
communication protocol (IICP) for the purpose of connecting an ITS test system to an implementation
under test (IUT) residing in a system under test (SUT).
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 21217:2014, Intelligent transport systems — Communications access for land mobiles (CALM) —
Architecture
ISO 24102-3, Intelligent transport systems — Communications access for land mobiles (CALM) — ITS
station management — Part 3: Service access points
ISO 24102-4, Intelligent transport systems — Communications access for land mobiles (CALM) — ITS
station management — Part 4: Station-internal management communications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp/
3.1
implementation under test
IUT
part of a real system which is to be studied by testing
3.2
system under test
SUT
real system in which an IUT (3.1) resides
4 Abbreviated terms
CI communication interface
IIC ITS-S internal management communications
IICA IIC agent
© ISO 2017 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO/TS 20026:2017(E)

IICM IIC manager
IICP IIC protocol
ITS intelligent transport systems
ITS-SCU ITS station communication unit
ITS-SCU-ID ITS-SCU identifier
PCO point of control and observation
PDU protocol data unit
TTCN-3 testing and test control notation version 3
5 Conventions
In this document, text presented in Courier font indicates ASN.1 codes.
6 Test system architecture
6.1 General
The general test system architecture is illustrated in Figure 1. It shows how an implementation under
test (IUT) contained in a system under test (SUT) is connected to the ITS test system via a lower
layers link and an upper tester transport link and a configuration/notification link. These links allow
accessing the points of control and observation (PCO) of the IUT.
Figure 1 — General conformance test system architecture
The lower layers link may end up in the SUT at the block “ITS lower layers”, in case lower layers are used
during testing, or directly at the lower interface of the IUT. The upper tester transport link ends up in the
SUT at the block “upper tester transport”. This “upper tester transport” block together with the “upper
tester application” block provides the test access to the upper interface of the IUT. The configuration
2 © ISO 2017 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/TS 20026:2017(E)

and event notification link is needed for testing of some IUTs, e.g. to set initial conditions and to retrieve
status information, allowing remote access to the management/security SAPs in the SUT.
The links shown in Figure 1 between the ITS test system and the SUT indicate connectivity between
entities in the two systems and the physical implementation of these links is implementation dependent.
For example, the three logical links shown may be implemented on a single physical communication
medium such as a single Ethernet connection between the ITS test system and the SUT.
Following the ITS station and communication architecture specified in ISO 21217 (see Figure 2), an IUT
can be a protocol or an ITS-S application process located in the
— ITS-S access layer (e.g. ITS-M5 specified in ISO 21215/ISO 21218),
— ITS-S networking and transport layer (e.g. FNTP specified in ISO 29281-1),
— ITS-S facilities layer (e.g. the LDM specified in ISO 18750),
— ITS-S management entity, or
— ITS-S security entity.
Figure 2 — ITS station architecture
An IUT may include functionalities in more than one architectural layer, for example, functionality in the:
— ITS-S access layer and the ITS-S networking and transport layer;
© ISO 2017 – All rights reserved 3

---------------------- Page: 8 ----------------------
ISO/TS 20026:2017(E)

— ITS-S networking and transport layer and the ITS-S facilities layer;
— ITS-S facilities layer and the ITS-S applications entity;
— ITS-S access layer and the ITS-S networking and transport layer and the ITS-S facilities layer;
— ITS-S networking and transport layer and the ITS-S facilities layer and the ITS-S applications entity;
— ITS-S access layer and the ITS-S networking and transport layer and the ITS-S facilities layer and the
ITS-S applications entity.
Additionally, an IUT may also include functionality in the ITS-S management entity and the ITS-S
security entity.
Regardless of the functionalities under test, the IUT in principle has these three PCOs shown in Figure 1.
The IUT may be accessed using the ITS station-internal management communications protocol (IICP)
specified in ISO 24102-4, as illustrated in 6.2 and 6.3. 6.2 describes the general IICP test architecture,
while 6.3 describes the extention of 6.2 needed in case the ITS-S access layer is used in the SUT. The
general IICP reference architecture is illustrated in 6.4.
6.2 IICP test system architecture without test CI
When the IUT does not involve access layer functionality, and applying IICP, the three links in Figure 1
are reduced to one physical link, e.g. an Ethernet cable with RJ45 connectors, as illustrated in Figure 3.
The ITS test system and the SUT, together, act as parts of a “virtual” ITS station unit (ITS-SU) where
each of these two units constitutes an ITS station communication unit (ITS-SCU) as specified in
ISO 21217. The ITS-SCU-ID (address of an ITS-SCU) of the ITS test system has the value 3 as specified
in ISO 24102-4. The ITS-SCU-ID of the SUT for the purpose of conformance testing is within the valid
range specified in ISO 24102-4.
Figure 3 — IICP-based simple conformance test system architecture
The dispatcher in Figure 3 needs to know the actually valid configuration of the ITS-SCU and the IUT in
order to properly establish the three links between SUT and ITS test system. Details of the dispatcher
are specified in Clause 10.
4 © ISO 2017 – All rights reserved

---------------------- Page: 9 ----------------------
ISO/TS 20026:2017(E)

6.3 IICP test system architecture with test CI
For some conformance tests (e.g. testing of an ITS-S access technology or using an ITS-S access
technology as “lower layer” below an IUT), a separate test CI is used as illustrated in Figure 4. This test
CI constitutes a third ITS-SCU of the “virtual” test ITS-SU. The ITS-SCU-ID of the test CI has the value 4
as specified in ISO 24102-4.
Figure 4 — IICP-based conformance test system architecture with test CI
The ltPort connects to the test CI using IICP. The test CI connects to the IUT using the respective ITS
communication link. Thus, the test CI just performs a conversion between the ITS-S access layer stream
and the ITS-ASDU of the IN-SAP (see ISO 21217:2014, Figure 12). The test CI is considered to be a “golden
device” that does not introduce any errors that could lead to a wrong result in conformance testing.
The dispatcher in Figure 4 needs to know the actual valid configuration in order to properly establish
the three links between the SUT and ITS test system. By detecting ITS-SCU-ID=4, the dispatcher knows
that a test CI is involved.
6.4 IICP reference architecture
The IICP reference architecture specified in ISO 24102-4 is illustrated in Figure 5.
© ISO 2017 – All rights reserved 5

---------------------- Page: 10 ----------------------
ISO/TS 20026:2017(E)

Figure 5 — IICP reference architecture
The IICP essentially is performed in the IICM presented in Figure 5. The IICA just performs forwarding
of IICP PDUs between the MF-SAP and the NF-SAP. IICA uses a link between the SUT and the ITS test
system, e.g. UDP/IP with dynamically assigned UDP port numbers or FNTP with the ITS port number
PORT_IIC = 32764 specified in ISO 24102-4.
IICP, in general, provides four different groups of functions as specified in ISO 24102-4:
a) simulation of a communication SAP (IN-SAP, NF-SAP, FA-SAP) in a management SAP for upper and
lower tester access;
b) remote access to a management SAP (MX-SAP):
— MA-SAP: for an IUT in the ITS-S applications entity;
— MF-SAP: for an IUT in the ITS-S facilities layer;
— MN-SAP: for an IUT in the ITS-S networking and transport layer;
— MI-SAP: for an IUT in the ITS-S access layer;
— MS-SAP: for an IUT in the ITS-S security entity;
c) general commands to be executed in a remote ITS-S management entity;
d) IICP-internal commands used to maintain IICP.
Two types of IICP messages to be exchanged between ITS-S management entities of ITS-SCUs are
defined in ISO 24102-4, i.e. IIC-Request and IIC-Response. IICP messages are exchanged between the
dispatcher in the test adapter and the ITS-S management entities in the SUT and the test CI via the
station-internal network of the “virtual” ITS-SU constituted by the two or three ITS-SCUs, i.e. the ITS
test system, the SUT and optionally, the test CI as illustrated in Figures 3 and 4.
6 © ISO 2017 – All rights reserved

---------------------- Page: 11 ----------------------
ISO/TS 20026:2017(E)

Each IIC-Request containing a payload to be used for testing shall be acknowledged with an empty IIC-
Response, thus IIC-Responses are not visible to the TTCN-3 test system, but are completely managed
inside the dispatcher. The payloads of IIC-Requests are MX-SAP functions presented in Table 4 (utPort),
Table 5 (ltPort) and Table 6 (cnPort). These functions perform remote SAP access on MX-SAPs and remote
requests to perform actions inside an ITS-S management entity. Only the payload part presenting the
content of such a remote request is either produced in the TTCN-3 test system or consumed there. Thus,
the dispatcher in the test adapter performs packing and unpacking of remote requests for the three
TTCN-3 ports.
As in some tests, e.g. the testing of IICP, exchange of IIC-Requests and IIC-Responses may be part of the
protocol to be tested, a capability is needed to distinguish between IIC-Requests and IIC-Responses
used to exchange test information and IIC-Requests and IIC-Responses being part of the IUT behaviour.
This distinction is done by means of the IICP address, ITS-SCU-ID contained in the SourceITS-SCU-ID
and DestinationITS-SCU-ID fields of these messages. The unique address of the ITS test system ITS-SCU
is ITS-SCU-ID = 3 as specified in ISO 24102-4. The unique address ITS-SCU-ID of the SUT is in the range
of 8 through 66 534 and may be selected by different means, e.g. using the initialisation procedure of
IICP specified in ISO 24102-4 or by static settings. In case IIC-Requests and IIC-Responses are part of
the IUT protocol, then a second set of ITS-SCU-IDs is needed; one value to be used in the TTCN-3 test
system and another value used in the SUT to serve the needs of the IUT.
7 IICP usage for conformance testing
7.1 General
The following subclauses specify details of IICP to perform conformance testing, e.g. by “simulation” of
communication SAPs and by remote execution of management and security commands.
7.2 IUT in an ITS-S communications layer
7.2.1 ITS-S access layer
For an IUT in the ITS-S access layer, the IICP test architecture presented in Figure 4 applies.
IN-SAP test access shall be performed as illustrated in Figure 6 using the IICP command:
— SimIUTcmd:
— upper tester access from ITS test system (utPort) to SUT (MI-SAP)
— lower tester access from ITS test system (ltPort) to Test CI (MI-SAP)
— SimIUTreq:
— upper tester access from SUT (MI-SAP) to ITS test system (utPort)
— lower tester access from Test CI (MI-SAP) to ITS test system (ltPort)
specified in ISO 24102-4 with
— SimIUTcmd::=INsapPrimitivesDown,
— SimIUTreq::=INsapPrimitivesUp
specified in ISO 24102-3.
© ISO 2017 – All rights reserved 7

---------------------- Page: 12 ----------------------
ISO/TS 20026:2017(E)

IN-SAP
MI-rcmd (SimIUTcmd)
(INsapPrimitivesDown)
ITS-S access layer
MI-rreq (SimIUTreq)
(INsapPrimitivesUp)
Figure 6 — IN-SAP simulation for IUT in ITS-S access layer
In addition to using these service primitives, the SUT shall be set to a test mode such that the IN-SAP is
disabled and replaced by the simulated access via the MI-SAP. This setting shall be activated using IICP
as specified in Annex A.
In order to perform settings in the IUT and to receive notifications of events from the IUT (cnPort),
remote access to the MI-SAP specified in ISO 24102-4 shall be used:
— IICP MI-rcmd: sent from test adapter (cnPort) to perform an initial setting in the IUT;
— IICP MI-rreq: to receive a notification from the IUT that is forwarded from the test adapter to
the cnPort;
— IICP MI-rget: sent from test adapter (cnPort) to retrieve an I-Parameter value from the IUT. The
requested value is returned in a separate IIC-Request;
— IICP MI-rset: sent from test adapter (cnPort) to set an I-Parameter value in the IUT. The
acknowledgement of the set command is returned in a separate IIC-Request.
7.2.2 ITS-S networking and transport layer
For an IUT in the ITS-S networking and transport layer, the lower layers link of Figure 1 may end up
directly at the IUT such that no ITS lower layers block is to be considered (test architecture presented
in Figure 3 applies) or at the ITS lower layers block (test architecture presented in Figure 4 applies).
In case no ITS-S access layer is used (lower layers block), the IN-SAP shall be disabled using IICP as
specified in Annex A and the access to the IN-SAP shall be performed as illustrated in Figure 7 using the
IICP remote access to the MN-SAP:
— SimNLTcmd: lower tester access from ITS test system (ltPort) to SUT (MN-SAP)
— SimNLTreq: lower tester access from SUT (MN-SAP) to ITS test system (ltPort)
specified in ISO 24102-4 with
— SimNLTcmd::=INsapPrimitivesUp,
— SimNLTreq::=INsapPrimitivesDown
specified in ISO 24102-3.
NF-SAP test access shall be performed as illustrated in Figure 7 using the IICP command:
— SimNUTcmd: upper tester access from ITS Test System (utPort) to SUT (MN-SAP)
8 © ISO 2017 – All rights reserved
MI-SAP

---------------------- Page: 13 ----------------------
ISO/TS 20026:2017(E)

— SimNUTreq: upper tester access from SUT (MN-SAP) to ITS Test System (utPort)
specified in ISO 24102-4 with
— SimNUTcmd::=NFsapPrimitivesDown,
— SimNUTreq::=NFsapPrimitivesUp
specified in ISO 24102-3.
In addition to using these service primitives, the SUT shall be set to a test mode such that the NF-SAP is
disabled and replaced by the simulated access via the MN-SAP. This setting shall be activated using IICP
as specified in Annex A.
NF-SAP
MN-rcmd (SimNLTcmd)
(INsapPrimitivesUp))
MN-rcmd (SimNUTcmd)
(NFsapPrimitivesDown)
ITS-S networking and transport layer
MN-rreq (SimNUTreq)
(NFsapPrimitivesUp)
MN-rreq (SimNLTreq)
(INsapPrimitivesDown)
IN-SAP
Figure 7 — IN-SAP and NF-SAP simulation for IUT in ITS-S networking and transport layer
In order to perform settings in the IUT and to receive notifications of events from the IUT, remote access
to the MN-SAP specified in ISO 24102-4 shall be used:
— IICP MN-rcmd: sent from test adapter (cnPort) to perform an initial setting in the IUT;
— IICP MN-rreq: to receive a notification from the IUT that is forwarded from the test adapter to
the cnPort.
7.2.3 ITS-S facilities layer
For an IUT in the ITS-S facilities layer, the lower layers link of Figure 1 may end up directly at the IUT
such that no ITS lower layers block is to be considered (test architecture presented in Figure 3 applies)
or at the ITS lower layers block (test architecture presented in Figure 4 applies). In case no ITS-S
networking and transport layer and no ITS-S access layer are used (lower layers block), the NF-SAP
shall be disabled using IICP as specified in Annex A and the access to the NF-SAP shall be performed as
illustrated in Figure 8 using the IICP remote access to the MF-SAP:
— SimFLTcmd: lower tester access from ITS test system (ltPort) to SUT (MF-SAP)
— SimFLTTreq: lower tester access from SUT (MF-SAP) to ITS test system (ltPort)
specified in ISO 24102-4 with
— SimFLTcmd::=NFsapPrimitivesUp,
— SimFLTreq::=NFsapPrimitivesDown
© ISO 2017 – All rights reserved 9
MN-SAP

---------------------- Page: 14 ----------------------
ISO/TS 20026:2017(E)

specified in ISO 24102-3.
FA-SAP test access shall be performed as illustrated in Figure 8 using the IICP command:
— SimFUTcmd: upper tester access from ITS test system (utPort) to SUT (MF-SAP)
— SimFUTreq: upper tester access from SUT (MF-SAP) to ITS test system (utPort)
specified in ISO 24102-4 with
— SimFUTcmd::=FAsapPrimitivesDown,
— SimFUTreq::=FAsapPrimitivesUp
specified in ISO 24102-3.
In addition to using these service primitives, the SUT shall be set to a test mode such that the FA-SAP is
disabled and replaced by the simulated access via the MF-SAP. This setting shall be activated using IICP
as specified in Annex A.
FA-SAP
MF-rcmd (SimFLTcmd)
(NFsapPrimitivesUp))
MF-rcmd (SimFUTcmd)
(FAsapPrimitivesDown)
ITS-S facilities layer
MF-rreq (SimFUTreq)
(FAsapPrimitivesUp)
MF-rreq (SimFLTreq)
(NFsapPrimitivesDown)
NF-SAP
Figure 8 — NF-SAP and FA-SAP simulation for IUT in ITS-S facilities layer
In order to perform settings in the IUT and to receive notifications of events from the IUT, remote access
to the MF-SAP specified in ISO 24102-4 shall be used:
— IICP MF-rcmd: sent from test adapter (cnPort) to perform an initial setting in the IUT;
— IICP MF-rreq: to receive a notification from the IUT that is forwarded from the test adapter to
the cnPort.
7.3 IUT in the ITS-S management entity
This will be provided in a future edition of this document.
7.4 IUT in the ITS-S security entity
This will be provided in a future edition of this document.
10 © ISO 2017 – All rights reserved
MF-SAP

---------------------- Page: 15 ----------------------
ISO/TS 20026:2017(E)

8 Setting to test mode
Operating the SUT in test mode requires the following information:
a) location of the IUT, which defines the interface(s) of the IUT for upper (/lower) tester access:
— ITS-S access layer: upper tester access is via IN-SAP;
— ITS-S networking and transport layer: upper/lower tester access is via NF-SAP;
— ITS-S facilities layer: upper/lower tester access is via FA-SAP;
— ITS-S management entity: upper/lower tester access is via MX-SAPs;
— ITS-S security entity (not supported in this document);
— ITS-S application entity (not supported in thi
...