ISO/TS 17423:2014

TECHNICAL ISO/TS
SPECIFICATION 17423
First edition
2014-04-15
Intelligent transport systems —
Cooperative systems — ITS application
requirements and objectives for
selection of communication profiles
Systèmes intelligents de transport — Systèmes coopératifs —
Exigences d’application d’ITS pour sélection d’interfaces de
communication
Reference number
ISO/TS 17423:2014(E)
©
ISO 2014

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ISO/TS 17423:2014(E)

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ISO/TS 17423:2014(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Communication service parameters . 4
5.1 Abstraction of application processes from communications . . 4
5.2 Communication service parameter classes . 7
5.3 Operational communication service parameters . 8
5.4 Destination communication service parameters . 9
5.5 Performance communication service parameters .10
5.6 Security communication service parameters .12
5.7 Protocol communication service parameter .12
5.8 Communication service parameters overview .13
6 Policies and regulations .14
6.1 Cost policy .14
6.2 Need for station anonymity .16
6.3 Need for station location privacy .16
6.4 Support of station authentication.16
7 ITS-S procedures for ITS-S communication profile selection .16
7.1 Overview .16
7.2 Presentation of communication service parameters .16
7.3 Monitoring of capabilities of communications .17
7.4 Monitoring of regulations and policies .18
7.5 Selection of ITS-S communication profiles .18
7.6 Interaction with user of ITS-SU .18
7.7 Support of other application processes .18
Annex A (normative) ASN.1 modules .20
Annex B (informative) Example of presentation of communication service parameters .26
Annex C (informative) On communication requirements and objectives .29
Bibliography .32
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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. 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. 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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
ISO/TS 17423 was prepared by the European Committee for Standardization (CEN) Technical Committee
CEN/TC 278, Intelligent transport systems, in collaboration with ISO Technical Committee ISO/TC 204,
Intelligent transport systems, in accordance with the Agreement on technical cooperation between ISO
and CEN (Vienna Agreement).
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ISO/TS 17423:2014(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.
Applications and communications are linked together using the concepts of flows and paths and
communication profiles described in ISO 21217 with related flow and path management procedures
specified in Reference [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 requirements is
referred to as a Flow Type in Reference [6]. There may be well-known registered Flow Types as specified
in ISO/TS 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
information of the next hop recipient, the anchor and the destination as specified in Reference [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.
[1]
1) The term “Cooperative ITS” (C-ITS) indicates specific features of ITS . For the purpose of this Technical
Specification, no distinction between ITS and C-ITS is needed.
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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.
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TECHNICAL SPECIFICATION ISO/TS 17423:2014(E)
Intelligent transport systems — Cooperative systems — ITS
application requirements and objectives for selection of
communication profiles
1 Scope
This Technical Specification
— 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, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 21217, Intelligent transport systems — Communications access for land mobiles (CALM) — Architecture
ISO 21218, Intelligent transport systems — Communications access for land mobiles (CALM) — Access
technology support
ISO/TS 17419, Intelligent transport systems — Cooperative systems — Classification and management of
ITS applications in a global context
ISO 24102-3, Intelligent transport systems — Communications access for land mobiles (CALM) — ITS station
management — Part 3: Service access points
ISO/IEC 8825-2, Information technology — ASN.1 encoding rules: Specification of Packed Encoding Rules
(PER) — Part 2
ISO 4217:2008, Codes for the representation of currencies and funds
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/TS 17419, ISO 21217, ISO 21218
and the following apply.
3.1
authorization
prescription that a particular behaviour shall not be prevented
Note 1 to entry: Unlike a permission, an authorization is an empowerment.
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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
EXAMPLE ITS-S applications, ITS-S facility applications (e.g. for CAM), ITS-S management applications (e.g.
[5]
FSAP ).
3.3
ITS application
instantiation of an ITS service that involves an association of two or more complementary ITS-S
application processes (3.2)
3.4
ITS service
functionality provided to users of intelligent transport systems designed e.g. to increase safety,
sustainability, efficiency, or comfort
3.5
ITS-S application
ITS-S application process (3.2) residing in the ITS-S application (3.3) entity
3.6
ITS-S application process provisioner
functionality in an ITS-SU offering ITS-S application processes (3.2) for download to other ITS-SUs
3.7
ITS-S communication profile
parameterized ITS-S communication protocol stack
3.8
ITS-S communication protocol stack
set of ITS-S communication protocols, which may be identified by a registered globally unique reference
number, enabling communications between an ITS-SCU and other nodes
3.9
ITS-S RX/TX interface
sink or source of an ITS-S application process (3.2)
3.10
permission
rule that a particular behaviour is allowed to occur
4 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”
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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_NxRepeat Communication service parameter “N-times ADU repetition”
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”
[6]
FlowID Flow Identifier
[4]
IICP ITS station-internal management communications protocol
ITS-S ITS station, see ISO 21217
ITS-SCP ITS station communication profile
ITS-SCPS ITS station communication protocol stack
ITS-SCU ITS station communication unit, see ISO 21217
ITS-SU ITS station unit, see ISO 21217
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
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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
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/TS 17419, is enabled by
— abstraction of ITS-S application processes (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, and
— procedures by which instances of ITS-S application processes running in an ITS station unit (ITS-
SU) specified in ISO 21217 can present requirements for communication services in an abstract and
standardized way to the ITS station management as specified in this Technical Specification, and
— 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 as
identified in this Technical Specification. 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 that needs to be extremized
(maximized or minimized) as discussed in Annex C.
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Figure 2 — ITS station architecture [from ISO 21217]
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),
[5]
— ITS-S application processes located in the ITS-S management entity (e.g. SAM and CTX sources ),
— ITS-S application processes located in the ITS-S security entity, and
— ITS-S application processes located somewhere else in an ITS station.
There are also other application processes that can get access to the communication tools 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 and ISO/TS 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.
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Figure 3 — Simplified architecture
Application processes are classified in ISO/TS 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:
The definitions of “authorized” and “permitted” are given in Reference [12].
Communication service parameters are specified in 5.3, 5.4, 5.5, 5.6 and 5.7. An overview is presented in
5.8. An ITS-S application process shall present the mandatory communication service parameters, and
may present those optional communication service parameters which are relevant for it.
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 Regulations are enforceable rules. Policies are rules or guidelines which cannot be enforced.
2)
An ITS-S application process may have more than one communication source , 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 InterfaceNo specified in
ISO/TS 17419 which is unique in the scope of that ITS-S application process. For each communication
2) An ITS-S application process might need to maintain flows for different communication sources, e.g. audio, video
and messages (e.g. SPaT, IVI, CAM, DENM, .).
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source an ITS-S application process presents a set of communication requirements to the ITS-S
management as specified in this Technical Specification. Such a set of communication requirements is
linked to an ITS flow type identifier (ITS-FlowTypeID). ITS-FlowTypeIDs may be well-known registered
identifiers pointing to pre-defined well-known sets of requirements as specified in ISO/TS 17419, or
may be dynamically assigned in an ITS-SU.
Communication service parameters 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. 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 refuse 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.
Once a FlowID has been assigned to an ITS-S application process, the ITS-S application process cannot
[6]
update communication service parameters associated with the flow.
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
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, in 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 Technical Specification.
Management procedures and service primitives related to these communication service parameters 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
Communication service parameters are grouped into classes. The following communication service
parameter classes are identified in this Technical Specification:
— The class of operational parameters is specified in 5.3.
— The class of destination parameters is specified in 5.4.
— The class of performance parameters is specified in 5.5.
— The class of security parameters is specified in 5.6.
— The class of protocol parameters is specified in 5.7.
— An overview of all parameters identified in this Technical Specification is presented in 5.8.
Some communication service parameters are mandatory, i.e. shall be presented by all ITS-S application
processes as specified in 7.2.
ASN.1 specifications of the communication service parameters are provided in Annex A.
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5.3 Operational communication service parameters
5.3.1 List of requirements
Operational communication service parameters specified in this Technical Specification 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 5.3.7.
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/TS 17419.
Logical channels are subject to registration as specified in ISO/TS 17419. Some examples of logical
channels are presented in Table 1.
Table 1 — Examples of logical channels
Acronym Name Description
CCH Control channel For dissemination and exchange of basic channel control infor-
mation, communication information, and application manage-
ment information.
SaCH Service advertisement channel For advertising of applications and services currently being
offered by an ITS-SU with service provider role, e.g. using FSAP.
[5]
SfCH Safety of life and property chan- For dissemination and exchange of safety of life and property
nel 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
ContConnect specified in Annex A.
CSP_SessionCont is a binary flag indicating whether a session may be interrupted or not. In case the
binary flag is set to zero, an active session should not be interrupted by the ITS-S management.
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5.3.4 Average ADU generation rate
CSP_AvgADUrate indicates the average rate 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/TS 17419 which uniquely points to a set of pre-defined communication service parameters. CSP_
FlowType shall be of ASN.1 type FlowTypeID specified in Annex A.
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 communication service parameter that consists of two parts, a direction
indicator of ASN.1 type PortRxTx and the port number of ASN.1 type PortNumber. 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/TS 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 unkn
...