EN ISO 17423:2018

SLOVENSKI STANDARD
01-september-2018
1DGRPHãþD
SIST-TS CEN ISO/TS 17423:2014
Inteligentni transportni sistemi - Kooperativni sistemi - Zahteve in cilji (ISO
17423:2018)
Intelligent transport systems - Cooperative systems - Application requirements and
objectives (ISO 17423:2018)
Intelligente Transportsysteme - Kooperative Systeme - ITS Anwendungsanforderungen
und Grundsätze (ISO 17423:2018)
Systèmes de transport intelligents - Systèmes coopératifs - Exigences d'application et
objectifs (ISO 17423:2018)
Ta slovenski standard je istoveten z: EN ISO 17423:2018
ICS:
03.220.01 Transport na splošno Transport in general
35.240.60 Uporabniške rešitve IT v IT applications in transport
prometu
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 17423
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2018
EUROPÄISCHE NORM
ICS 03.220.20; 35.240.60 Supersedes CEN ISO/TS 17423:2014
English Version
Intelligent transport systems - Cooperative systems -
Application requirements and objectives (ISO
17423:2018)
Systèmes de transport intelligents - Systèmes Intelligente Transportsysteme - Kooperative Systeme -
coopératifs - Exigences d'application et objectifs (ISO ITS Anwendungsanforderungen und Grundsätze (ISO
17423:2018) 17423:2018)
This European Standard was approved by CEN on 9 May 2018.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17423:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 17423:2018) has been prepared by Technical Committee ISO/TC 204
"Intelligent transport systems" in collaboration with Technical Committee CEN/TC 278 “Intelligent
transport systems” the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by December 2018, and conflicting national standards
shall be withdrawn at the latest by December 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes CEN ISO/TS 17423:2014.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 17423:2018 has been approved by CEN as EN ISO 17423:2018 without any modification.

INTERNATIONAL ISO
STANDARD 17423
First edition
2018-05
Intelligent transport systems —
Cooperative systems — Application
requirements and objectives
Systèmes de transport intelligents — Systèmes coopératifs —
Exigences d'application et objectifs
Reference number
ISO 17423:2018(E)
©
ISO 2018
ISO 17423:2018(E)
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

ISO 17423:2018(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
5 Communication service parameters . 4
5.1 Abstraction of application processes from communications . . 4
5.2 Communication service parameter classes . 7
5.3 Operational CSPs . 8
5.3.1 List of CSPs . 8
5.3.2 Logical channel . 8
5.3.3 Session continuity . 8
5.3.4 Average ADU generation rate . 9
5.3.5 Flow type . 9
5.3.6 Maximum priority . 9
5.3.7 Port number . 9
5.3.8 Expected flow lifetime . . 9
5.4 Destination CSPs . 9
5.4.1 List of CSPs . 9
5.4.2 Destination type .10
5.4.3 Destination domain .10
5.4.4 Communication distance .10
5.4.5 Directivity .10
5.5 Performance CSPs .11
5.5.1 List of CSPs .11
5.5.2 Resilience .11
5.5.3 Minimum required throughput .11
5.5.4 Maximum allowed latency .11
5.5.5 Maximum ADU size .12
5.6 Security CSPs .12
5.6.1 List of CSPs .12
5.6.2 Need for data confidentiality .12
5.6.3 Need for data integrity . .12
5.6.4 Need for non-repudiation .12
5.6.5 Need for source ITS-S application process authentication.12
5.7 Protocol CSP .13
5.7.1 List of CSPs .13
5.7.2 Communication protocol stack.13
5.7.3 Specific communications protocols .13
5.8 CSPs for sinks .13
5.9 CSPs overview .14
6 Policies and regulations .15
6.1 Cost policy .15
6.1.1 List of rules .15
6.1.2 Flat rate .15
6.1.3 Maximum rate per data unit .16
6.1.4 Maximum rate per connection time .16
6.1.5 Maximum rate per connection .16
6.2 Need for station anonymity .17
6.3 Need for station location privacy .17
6.4 Support of station authentication.17
ISO 17423:2018(E)
7 ITS-S procedures for ITS-S communication profile selection .17
7.1 Overview .17
7.2 Presentation of CSPs .18
7.3 Monitoring of capabilities of communications .18
7.4 Monitoring of regulations and policies .19
7.5 Selection of ITS-S communication profiles .19
7.6 Interaction with user of ITS-SU .19
7.7 Support of other application processes .20
Annex A (normative) ASN.1 modules .21
Annex B (informative) Example of presentation of CSPs .28
Annex C (informative) On communication requirements and objectives .31
Bibliography .34
iv © ISO 2018 – All rights reserved

ISO 17423:2018(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: www .iso .org/iso/foreword .html.
This document was prepared by ISO/TC 204, Intelligent transport systems.
This first edition cancels and replaces ISO/TS 17423:2014, which has been technically revised.
ISO 17423:2018(E)
Introduction
Abstracting applications from communications is a useful basic architectural principle of Intelligent
1)
Transport Systems (ITS) embodied in the ITS station and communication architecture presented in
ISO 21217:2014.
Applications and communications are linked together using the concepts of flows and paths and
communication profiles described in ISO 21217:2014 with related flow and path management
2)
[11]
procedures specified in ISO 24102-6 . The ITS station management uses communication
requirements and objectives of applications together with the capabilities of the ITS station (status of
available communication protocol stacks) and sets of decision rules (regulations and policies) to select
suitable parameterized ITS-S communication protocol stacks, also referred to as "ITS-S Communication
Profiles" (ITS-SCP), for each source of a potential flow as illustrated in Figure 1. A set of communication
[11]
requirements is referred to as a Flow Type in ISO 24102-6 . There may be well-known registered
Flow Types as specified in ISO 17419.
Figure 1 — ITS-S communication profile selection process
An ITS-S communication profile is independent of any destination address. However an instantiation
of a communication profile includes the address of the next hop recipient, and a path includes address
[11]
information of the next hop recipient, the anchor and the destination as specified in ISO 24102-6 .
A user of an ITS station unit may be able to influence the selection of ITS-S communication profiles by
providing his own policies.
Information from a Local Dynamic Map (LDM) on neighbouring stations offering certain communication
capabilities may also be useful for the ITS-S communication profile selection process, although not
indispensable.
1) The term “Cooperative ITS” (C-ITS) indicates specific features of ITS [4]. For the purpose of this document, no
distinction between ITS and C-ITS is needed.
2) To be published.
vi © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 17423:2018(E)
Intelligent transport systems — Cooperative systems —
Application requirements and objectives
1 Scope
This document
— specifies communication service parameters presented by ITS station (ITS-S) application processes
to the ITS-S management in support of automatic selection of ITS-S communication profiles in an
ITS station unit (ITS-SU),
— specifies related procedures for the static and dynamic ITS-S communication profile selection
processes at a high functional level,
— provides an illustration of objectives used to estimate an optimum ITS-S communication profile.
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 4217:2015, Codes for the representation of currencies
ISO/IEC 8824-1:2015, Information technology — Abstract Syntax Notation One (ASN.1): Specification of
basic notation
ISO 17419, Intelligent transport systems — Identifiers — Globally unique identification
ISO 21217:2014, Intelligent transport systems — Communications access for land mobiles (CALM) —
Architecture
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 https: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
3.1
authorization
prescription that a particular behaviour shall not be prevented
Note 1 to entry: Unlike a permission (3.10), an authorization is an empowerment.
[14]
Note 2 to entry: From ITU-T X.911 .
ISO 17423:2018(E)
3.2
ITS-S application process
element in an ITS station that performs information processing for a particular application and uses
ITS-S services to transmit and receive information
Note 1 to entry: Examples of ITS-S application processes are ITS-S applications, ITS-S facility applications (e.g. for
[10]
CAM), and ITS-S management applications (e.g. FSAP specified in ISO 22418 ).
[SOURCE: ISO 21217:2014, 3.19, modified — Note 1 to entry has been added.]
3.3
ITS application
instantiation of an ITS service that involves an association of two or more complementary ITS-S
application processes
[SOURCE: ISO 21217:2014, 3.9 — modified: Note 1 to entry was deleted.]
3.4
ITS service
functionality provided to users of intelligent transport systems designed e.g. to increase safety,
sustainability, efficiency, or comfort
[SOURCE: ISO 21217:2014, 3.11]
3.5
ITS-S application
ITS-S application process residing in the ITS-S application entity
[SOURCE: ISO 21217:2014, 3.18]
3.6
ITS-S application process provisioner
functionality in an ITS-SU offering ITS-S application processes for download to other ITS-SUs
[SOURCE: ISO 17419:2018, 3.14]
3.7
ITS-S communication profile
parameterized ITS-S communication protocol stack
3.8
ITS-S communication protocol stack
consistent set of ITS-S communication protocols enabling communications between an ITS-SCU and
other nodes which may be identified by a registered globally unique reference number
3.9
ITS-S application process RX/TX interface
sink or source of an ITS-S application process
3.10
permission
rule that a particular behaviour is allowed to occur
[14]
Note 1 to entry: From ITU-T X.911 .
2 © ISO 2018 – All rights reserved

ISO 17423:2018(E)
4 Symbols and abbreviated terms
BSME Bounded Secured Managed Entity, see ISO 21217
CPSP Communication Profile Selection Process
CRO Communication Requirements and Objectives
CSP Communication Service Parameter
CSP_AvgADUrate Communication service parameter “Average ADU generation rate”
CSP_CommDistance Communication service parameter “Communication distance”
CSP_DataConfidentiality Communication service parameter “Need for data confidentiality”
CSP_DataIntegrity Communication service parameter “Need for data integrity”
CSP_DestinationDomain Communication service parameter “Destination domain”
CSP_DestinationType Communication service parameter “Destination type”
CSP_Directivity Communication service parameter “Directivity”
CSP_ExpFlowLifetime Communication service parameter “Expected flow lifetime”
CSP_FlowType Communication service parameter “Flow type”
CSP_LogicalChannelType Communication service parameter “Logical channel”
CSP_MaxADU Communication service parameter “Maximum ADU size”
CSP_MaxLat Communication service parameter “Maximum allowed latency”
CSP_MaxPrio Communication service parameter “Maximum priority”
CSP_MinThP Communication service parameter “Minimum throughput”
CSP_NonRepudiation Communication service parameter “Need for non-repudiation”
CSP_PortNo Communication service parameter “Port Number”
CSP_Protocol Communication service parameter “Protocol requirements”
CSP_Resilience Communication service parameter “Resilience”
CSP_SessionCont Communication service parameter “Session continuity”
CSP_SourceAuthentication Communication service parameter “Source authentication”
CSP_SpecificCommsProts Communication service parameter “Specific communications protocols”
[11]
ITS-S-FlowID Flow Identifier, see ISO 24102-6
IICP ITS station-internal management communications protocol, see
[9]
ISO 24102-4
ITS-S ITS station, see ISO 21217:2014
ITS-SCP ITS station communication profile
ISO 17423:2018(E)
ITS-SCPS ITS station communication protocol stack
ITS-SCU ITS station communication unit, see ISO 21217:2014
ITS-SU ITS station unit, see ISO 21217:2014
R_ConnectRate “Maximum rate per connection” rule
R_ConnectTimeRate “Maximum rate per connection time” rule
R_DataUnitRate “Maximum rate per data unit” rule
R_FlatRate “Flat Rate” rule
R_StationAnonymity “Need for station anonymity” rule
R_StationAuthentication “Support of station authentication” rule
R_StationLocationPrivacy “Need for station location privacy” rule
ITS-S-FlowTypeID ITS-S flow type identifier (from ISO 24102-6)
5 Communication service parameters
5.1 Abstraction of application processes from communications
The ITS station (ITS-S) reference architecture presented in Figure 2 and specified in ISO 21217:2014
distinguishes two main blocks, i.e. "Applications" and "Communications". ITS-S application processes in
"Applications" access communication services in "Communications" through an API. Portability of ITS-S
application processes, which leads to the creation of ITS application process repositories as described
in ISO 17419, is enabled by
— abstraction of ITS-S application processes (e.g. in "Applications") from communication protocols
(in "Facilities", "Networking & Transport", "Access") and supporting management and security
functionality (in "Management", "Security") introduced as an essential basics of an ITS station in
ISO 21217:2014,
— procedures by which instances of ITS-S application processes running in an ITS station unit (ITS-SU)
specified in ISO 21217:2014 can present requirements for communication services in an abstract
and standardized way to the ITS station management as specified in this document,
— procedures for automatic selection of optimum communication profiles by the ITS station
management for each set of required communication services.
Communication service requirements are presented by means of "Communication Service Parameters"
(CSP) as identified in this document. These parameters are used to identify sets of possible choices
of ITS-S communication profiles as well as selecting the "optimal" ITS-S communication profile out of
each set. The selection of the "optimal" ITS-S communication profile is implementation dependent and
generally involves the formulation of a cost function based on objectives. The cost function needs to be
extremized (maximized or minimized) as discussed in Annex C.
4 © ISO 2018 – All rights reserved

ISO 17423:2018(E)
Figure 2 — ITS station architecture [ISO 21217:2014]
The same approach to present communication requirements and objectives also applies to
— ITS-S application processes located in the ITS-S facilities layer (e.g. CAM source, specified in ETSI
[15]
EN 302 637-2 ),
— ITS-S application processes located in the ITS-S management entity (e.g. SAM and SRM sources
[1] [10]
specified in ISO/TS 16460 and ISO 22418 ),
— ITS-S application processes located in the ITS-S security entity,
— ITS-S application processes located somewhere else in an ITS station.
There are also other application processes that can get access to the communication services of an
ITS-SU. Such other application processes are not certified to be installed in an ITS-SU implemented
as a BSME as described in ISO 21217:2014 and ISO 17419, but may use selected functionality from it,
especially communication functionality.
Figure 3 illustrates a simplified version of Figure 2 to be applied to the process illustrated in Figure 1
considering ITS-S application processes in general.
Figure 3 — Simplified architecture
ISO 17423:2018(E)
Application processes are classified in ISO 17419 as:
— ITS-S application processes certified for a BSME and identified by an ITS-AID (ITS-S facilities
applications, ITS-S management applications, ITS-S security applications and ITS-S applications):
— authorized ITS-S applications;
— permitted ITS-S applications;
— application processes not certified for a BSME and without ITS-AID.
[14]
The definitions of "authorized" and "permitted" are given in ITU-T X.911 .
CSPs for ITS-S application process sources are specified in 5.3, 5.4, 5.5, 5.6 and 5.7. An overview is
presented in 5.9. An ITS-S application process shall present the mandatory CSPs, and may present
those optional CSPs which are relevant for it. Mandatory CSPs shall be treated as optional in case CSP_
FlowType is presented.
Users of ITS-SUs may present rules, see Figure 1, by means of user policies, e.g. for cases where the ITS-S
application process did not specify a specific value (example: financial requirements). Requirements
may also be given by authorities in terms of regulations and policies, or by other entities in terms of
policies, see Figure 1.
NOTE 1 Regulations are enforceable rules. Policies are rules or guidelines which cannot be enforced.
3)
An ITS-S application process may have more than one communication source (/ sink) (ITS-S application
process RX/TX interface), and these communication sources may have different communication
requirements. Each communication source (and sink) of an ITS-S application process is identified by a
reference number of ASN.1 type ITSappProcSinkSourceNo specified in ISO 17419 which is unique
in the scope of that ITS-S application process. For each communication source an ITS-S application
process presents a set of communication requirements to the ITS-S management as specified in this
document. Such a set of communication requirements is linked to an ITS flow type identifier (ITS-S-
FlowTypeID). ITS-S-FlowTypeIDs may be well-known registered identifiers pointing to pre-defined
well-known sets of requirements or may be dynamically assigned in an ITS-SU.
Information contained in a registry for ITS flow types is given by the ASN.1 type ITSflowTypeRegistry
specified in Annex A. This registry shall contain entries for ITS flow types given by the ASN.1 type
ITSflowType specified in Annex A and listed in Table 1. A registration authority may add further
information elements to properly identify and support management of ITS flow types. A registration
authority shall clearly distinguish the range of well-known registered ITS-FlowTypeIDs and dynamically
assigned ITS-FlowTypeIDs.
NOTE 2 A general introduction on registries for unique identifiers in ITS is provided in ISO 17419.
Table 1 — Registry components of ITSflowType
Component of Semantics
ITSflowType
id FlowTypeID
req
List of applicable communication service parameters ITSSappCPReqReg. The communi-
cation service parameter CSP_FlowType presenting a value of ITS-FlowTypeID is prohibited
in req. The CostObjective used in some communication service parameters is not part
of a registered ITS flow type. Thus the value presented in the registry is not relevant. The
convention shall be to use the value 255 (maximum relevance) in the registry, and to replace
it by an applicable value upon usage.
CSPs presented by ITS-S application processes for each communication source are used by the ITS
station management to select the best suited ITS-S communication profile per communication source.
3) An ITS-S application process might need to maintain flows for different communication sources, e.g. audio,
video and messages.
6 © ISO 2018 – All rights reserved

ISO 17423:2018(E)
It might be that an ITS-S management is not able to provide a communication protocol stack which fully
complies with the requirements, i.e. fails to identify and select an appropriate ITS-S communication
profile. In this failure situation either a best effort approach to enable communications or a refusal to
support this particular communication source applies. In any case the ITS-S management reports the
status of the ITS-S communication profile selection procedure to the ITS-S application process.
[11]
Once a ITS-S-FlowID has been assigned to an ITS-S application process, see ISO 24102-6 , the ITS-S
application process can
— present ADUs for transmission,
— publish data objects, and
— subscribe to reception of data objects,
[3]
e.g. using the procedures specified in ISO/TS 17429:2017, Clause 8 .
[11]
Once a ITS-S-FlowID has been assigned to an ITS-S application process, see ISO 24102-6 , the ITS-S
application process cannot update CSPs associated with the flow.
An ITS-S application process may also present requirements on communication sinks (ITS-S application
process RX/TX interface), e.g. to request opening a receive port identified by an ITS port number (ITS-
PN). Similarly to the communication sources of an ITS-S application process these communication sinks
are uniquely identified by a reference number of ASN.1 type ITSappProcSinkSourceNo specified in
ISO 17419. CSPs for ITS-S application process sinks are specified in 5.8.
The interface between "Applications" and "Communications" illustrated in Figure 1 is an "Application
Programming Interface" (API). An API provides the functionality described in the service access points
[8]
MA-SAP, SA-SAP and FA-SAP specified in ISO 24102-3 . Details of APIs depend on the operating system
used to implement them.
ITS-S application processes may reside in the ITS-S application entity, the ITS-S facilities layer, in the
ITS-S security entity, and in the ITS-S management entity. The interaction between ITS-S application
processes and the ITS-S management entity is specified in terms of functions in the service primitives
of the MA-SAP, the MF-SAP, and the MS-SAP illustrated in Figure 2.
The specification of APIs for ITS is outside the scope of this document.
Management procedures and service primitives related to these CSPs are specified in Clause 7.
The normative Annex A provides an ASN.1 module with specifications of types and values used to
present the communication requirements and objectives.
5.2 Communication service parameter classes
CSPs are grouped into classes. The following communication service parameter classes are identified in
this document:
— The class of operational CSPs is specified in 5.3.
— The class of destination CSPs is specified in 5.4.
— The class of performance CSPs is specified in 5.5.
— The class of security CSPs is specified in 5.6.
— The class of protocol CSPs is specified in 5.7.
— CSPs relevant for ITS-S application process sinks, specified in 5.8
— An overview of all CSPs identified in this document is presented in 5.9.
Some CSPs are mandatory, i.e. shall be presented by all ITS-S application processes as specified in 7.2.
ISO 17423:2018(E)
ASN.1 specifications of the CSPs are provided in Annex A.
5.3 Operational CSPs
5.3.1 List of CSPs
Operational CSPs specified in this document are:
— "Logical channel" communication service parameter CSP_LogicalChannelType (mandatory) as
specified in 5.3.2;
— "Session continuity" communication service parameter CSP_SessionCont (optional) as specified
in 5.3.3;
— "Average ADU generation rate" communication service parameter CSP_AvgADUrate (optional) as
specified in 5.3.4;
— "FlowType" communication service parameter CSP_FlowType (optional) as specified in 5.3.5;
— "Maximum Priority" communication service parameter CSP_MaxPrio (optional) as specified in 5.3.6;
— "Port Number" communication service parameter CSP_PortNo (mandatory) as specified in 5.3.7;
— "Expected flow lifetime" communication service parameter CSP_ExpFlowLifetime (optional) as
specified in 5.3.8.
5.3.2 Logical channel
CSP_LogicalChannelType indicates the logical channel to be used for communications. It shall
always be presented by an ITS-S application process. CSP_LogicalChannelType shall be of ASN.1 type
LogicalChannelType specified in ISO 17419.
Logical channels are subject to registration as specified in ISO 17419. Some examples of logical channels
are presented in Table 2.
Table 2 — Examples of logical channels
Acronym Name Description
CCH Control channel For dissemination and exchange of basic channel control informa-
tion, communication information, and application management
information.
SaCH Service advertisement channel For advertising of applications and services e.g. using FSAP spec-
[10]
ified in ISO 22418 .
SfCH Safety of life and property channel For dissemination and exchange of safety of life and property
critical information.
SCH Service channel For exchange of peer to peer ITS-S application process data, and
for general message dissemination.
5.3.3 Session continuity
CSP_SessionCont indicates that the flow is related to a session. CSP_SessionCont shall be of ASN.1 type
SessionCont specified in Annex A.
SessionCont is a binary flag indicating whether a session may be interrupted or not. In case the
binary flag is set to one, an active session should not be interrupted by the station management.
8 © ISO 2018 – All rights reserved

ISO 17423:2018(E)
5.3.4 Average ADU generation rate
CSP_AvgADUrate indicates the repetition period (time) at which ADUs will be presented for
transmission. It is applicable only for information dissemination. CSP_AvgADUrate shall be of ASN.1
type AvgADUrate specified in Annex A.
The value zero indicates an unknown average rate.
In case CSP_AvgADUrate is not presented, then the value of zero shall apply.
5.3.5 Flow type
CSP_FlowType presents a well-known registered flow type identifier FlowTypeID specified in ISO 17419
which uniquely points to a set of pre-defined CSPs. CSP_FlowType shall be of ASN.1 type FlowTypeID
specified in Annex A.
When CSP_FlowType is presented, no other CSPs need to be presented including those indicated to be
mandatory. CSP_FlowType shall overrule other CSPs that conflict with the implicit CSPs identified by
CSP_FlowType.
5.3.6 Maximum priority
CSP_MaxPrio presents the maximum allowed priority for flows. In case CSP_MaxPrio is not present,
lowest priority 0 is assumed. CSP_MaxPrio shall be of ASN.1 type ITSapObPriority specified in
Annex A.
5.3.7 Port number
CSP_PortNo is a mandatory CSP that consists of two parts, a direction indicator of ASN.1 type PortRxTx
and the port number mappings of ASN.1 type PortNumberMappings. CSP_PortNo is presented
for communication sources and communication sinks to indicate a well-known port number to be
associated with the interface. CSP_PortNo shall be of ASN.1 type PortNoInfo specified in Annex A.
In case the given interface is not associated with a well-known port, the port number PORT_UNK
specified in ISO 17419 shall be presented.
5.3.8 Expected flow lifetime
CSP_ExpFlowLifetime indicates the expected lifetime of a flow. CSP_ExpFlowLifetime shall be of ASN.1
type ExpFlowLifeTime specified in Annex A.
ExpFlowLifeTime consists of a time information of ASN.1 type TimeDurationValue.
TimeDurationValue indicates the expected time for a flow. A time value of zero indicates "time
unknown".
In case CSP_ExpFlowLifetime is not presented, then the value of zero shall apply.
5.4 Destination CSPs
5.4.1 List of CSPs
Destination CSPs specified in this document are:
— "Destination type" communication service parameter CSP_DestinationType (mandatory) as
specified in 5.4.2.
— "Destination domain" communication service parameter CSP_DestinationDomain (mandatory) as
specified in 5.4.3.
ISO 17423:2018(E)
— "Communication distance" communication service parameter CSP_CommDistance (optional) as
specified in 5.4.4.
— "Directivity" communication service parameter CSP_Directivity (optional) as specified in 5.4.5.
NOTE Destination address information is provided by the ITS-S application process at time of ITS-S-FlowID
[11]
allocation, see ISO 24102-6 .
5.4.2 Destination type
CSP_DestinationType indicates the type of transmission. It shall always be presented by an ITS-S
application process. CSP_DestinationType is of ASN.1 type DestinationType specified in Annex A.
DestinationType indicates the following different casting types:
— 1: broadcast transmission;
— 2: multicast transmission to a defined multicast group;
— 4: unicast transmission to a specific station;
— 8: anycast transmission
...