ISO 24102-6:2018

Intelligent transport systems - Communications access for land mobiles (CALM) - ITS station management - Part 6: Path and flow management

This document specifies parameters and procedures for the ITS station management entity to manage data flows and routing paths associated with available communication resources in an ITS station, and to map data flows to routing paths.

Systèmes intelligents de transport — Accès aux communications des services mobiles terrestres (CALM) — Gestion des stations ITS — Partie 6: Titre manque

General Information

• Status: Published
• Publication Date: 10-May-2018
• ICS: 03.220.01 - Transport in general
• ICS: 35.240.60 - IT applications in transport
• Technical Committee: ISO/TC 204 - Intelligent transport systems
• Drafting Committee: ISO/TC 204/WG 16 - Communications
• Current Stage: 9093 - International Standard confirmed
• Start Date: 18-Oct-2022
• Completion Date: 13-Dec-2025

Overview

ISO 24102-6:2018 - "Intelligent transport systems - Communications access for land mobiles (CALM) - ITS station management - Part 6: Path and flow management" specifies the parameters and procedures an ITS station management entity uses to manage data flows and routing paths within an ITS station. The standard defines how the ITS station collects information (capabilities, neighbor capabilities, network conditions, existing flows and their requirements, and available routing paths) and how it maps identifiable ITS-S flows to selected routing paths and communication profiles (protocol stacks and access technologies).

Key topics and requirements

• Flow management: Parameters, monitoring and lifecycle operations for identifiable ITS-S flows (registration, release, statistics).
• Communication profile selection: Mapping application communication requirements to a parameterized ITS-S communication profile (protocol stack across layers: facilities, transport, network, access).
• Path management: Definition and management of ITS-S paths and anchor nodes, topological/geographic descriptors, path monitoring and availability checks.
• Path selection and routing policies: Criteria and notifications for choosing routing paths and applying routing policies.
• Capabilities management: Discovery, maintenance and activation/suspension of ITS-S capabilities (internal and neighbour capability information).
• Distributed ITS-S management model: Functions run as a distributed process (no central supervisory entity).
• Interfaces and information tables: Specification of management information tables, commands, requests and error codes to support path/flow operations.

Practical applications and users

ISO 24102-6 is intended for any ITS station implementation that needs robust multi-access communication and flexible routing of application traffic. Typical uses include:

• Vehicle OEMs and telematics suppliers implementing multi-protocol V2X (vehicle-to-everything) connectivity.
• ITS software architects and system integrators designing flow-aware routing and profile selection logic.
• Communication module vendors (cellular, ITS-G5/802.11p, DSRC) ensuring interoperability of access technologies.
• Road operators and traffic management centres coordinating cooperative systems and real-time services.
• Test laboratories and certification bodies validating ITS station management behavior against CALM requirements.

Related standards

• ISO 21217:2014 - ITS station reference architecture (CALM)
• ISO 17423:2018 - ITS application requirements for selection of communication profiles
• ISO/TS 17429:2017 - ITS station facilities for transfer of information
• ISO 24102-3 - Other ITS station management parts

ISO 24102-6:2018 is part of the CALM series and complements these documents by standardizing how flows and paths are described, monitored and mapped to communication resources - enabling resilient, multi-technology ITS communications and interoperable V2X services.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 24102-6
First edition
2018-05
Intelligent transport systems —
Communications access for land
mobiles (CALM) — ITS station
management —
Part 6:
Path and flow management
Systèmes intelligents de transport — Accès aux communications des
services mobiles terrestres (CALM) — Gestion des stations ITS —
Partie 6: Titre manque
Reference number
©
ISO 2018
© 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
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CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

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 Overview . 4
5.1 Relation with the ITS station reference architecture . 4
5.2 ITS-S flows. 4
5.3 ITS-S communication profiles . 4
5.4 ITS-S paths . 5
5.5 ITS-S capabilities . 6
5.6 Path and flow management . 6
5.7 ITS station management functionalities . 8
5.8 ITS station management information tables . . 9
5.9 Interaction with ITS station layers . 9
6 Requirements for flow management and communication profile selection .11
6.1 ITS-S flow type parameters .11
6.2 ITS-S flow parameters .13
6.3 ITS-S flow monitoring .14
6.4 Notification of a communication profile determination .15
6.5 Processing request to provide communication profiles .15
6.6 Processing flow statistic reports .15
7 Requirements for flow registration .16
7.1 Processing ITS-S flow type registration from ITS-S-AP .16
7.2 Processing RegisterFlow from ITS-S-AP .16
7.3 Processing ReleaseFlow request from ITS-S-AP .17
7.4 Checking ITS-S-AP credentials .17
7.5 Checking communication requirements .17
7.6 Checking ITS-S path availability .18
7.7 Communication profile determination .18
8 Requirements for path management .19
8.1 ITS-S path parameters .19
8.2 Topological and geographic position parameters .19
8.3 Collecting topological and geographical information.20
8.4 Path management .21
8.5 ITS-S path monitoring .21
8.6 Interface management .22
9 Requirements for path selection .22
9.1 General requirements for path selection . .22
9.2 Routing policies parameters .22
9.3 Notifying path selection .22
9.4 Notifying routing policies .23
10 Requirements for ITS-S capabilities management .23
10.1 Maintenance of ITS-S capabilities information .23
10.2 Determination of internal ITS-S capabilities .24
10.3 Determination of neighbour ITS-S capabilities .24
10.4 Activating ITS-S capabilities in the ITS-S Managed Service Entity .24
10.5 Suspending ITS-S capabilities in the ITS-S Managed Service Entity .24
10.6 Resuming ITS-S capabilities in the ITS-S Managed Service Entity .25
10.7 Reporting about ITS-S capabilities in the ITS-S Managed Service Entity .25
Annex A (normative) M*-COMMANDs from SME .26
Annex B (normative) M*-REQUESTs to the SME .37
Annex C (normative) PFM error codes .45
Annex D (normative) ASN-1 modules .46
Bibliography .64
iv © ISO 2018 – All rights reserved

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 Technical Committee ISO/TC 204, Intelligent transport systems.
A list of all parts in the ISO 24102 series can be found on the ISO website.
Introduction
This document is part of a series of International Standards for communications access for land mobiles
(CALM). An introduction to this series of International Standards is provided in ISO 21217:2014.
This document is Part 6 of a series of International Standards that specifies path and flow management
as part of the local ITS station management.
The ITS station management entity provides functionalities related to the management of communication
protocol layers and the security entity presented in the ITS station reference architecture specified in
ISO 21217:2014 and presented in Figure 1 — ITS station reference architecture.
Figure 1 — ITS station reference architecture
The ITS station management entity is specified as a distributed process, where no supervisory entity is
employed.
This document defines the functionalities of the ITS station that are used to collect the information
necessary for path and flow management:
— the capabilities of all layers of the ITS station (functionalities, technologies and protocols) supported
by the ITS station;
— the capabilities of neighbour ITS stations (functionalities, technologies and protocols) supported by
the neighbour ITS stations;
— the current network conditions (availability and characteristics of a communication interface,
availability of Internet access, etc.);
— the existing data flows and their communication requirements (identity of the destination node,
security procedures applied to the data flow, end-to-end delay, packet size, etc);
— the available routing paths to a destination node;
— how a data flow is mapped to the selected routing path.
The information collected by the ITS station management entity is used to determine the most
appropriate communication profile (facilities protocols, transport protocols, network protocols, access
technologies and communication channels) and routing path indicating where to route packets of each
vi © ISO 2018 – All rights reserved

data flow, according to the communication requirements provided by the application and depending on
the current network conditions. The method to perform this determination has competitive value and
is out of scope of this document.
This document provides a detailed specification of the concept of paths and flows introduced in
[17]
ISO 21217:2014. It complements ISO 17423:2018, ISO/TS 17429:2017, and ISO 24102-3 . The concept
of paths and flows is essential for abstracting ITS station applications from the communications
services available in the ITS station and for selecting the most appropriate communication profile (i.e.
protocol stack).
The functionalities specified in this document apply to all types of ITS stations without distinction. They
are useful for ITS stations equipped with various access technologies and/or various protocol stacks.
INTERNATIONAL STANDARD ISO 24102-6:2018(E)
Intelligent transport systems — Communications access
for land mobiles (CALM) — ITS station management —
Part 6:
Path and flow management
1 Scope
This document specifies parameters and procedures for the ITS station management entity to manage
data flows and routing paths associated with available communication resources in an ITS station, and
to map data flows to routing paths.
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 17423:2018, Intelligent transport systems — Cooperative systems — ITS application requirements and
objectives for selection of communication profiles
ISO/TS 17429:2017, Intelligent transport systems — Cooperative ITS — ITS station facilities for the transfer
of information between ITS stations
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 http: //www .electropedia .org/
—  ISO Online browsing platform: available at http: //www .iso .org/obp
3.1
anchor node
logical node contained in an ITS-S path which, when instantiated, has a locator known by the source node
3.2
destination node
communication end point of an ITS-S path
Note 1 to entry: In multicast operation, there can be many distinct destination nodes.
3.3
ITS-S egress anchor node
second (last) anchor node contained in an ITS-S path
3.4
ITS-S ingress anchor node
first anchor node contained in an ITS-S path
3.5
ITS-S anchor segment
segment of an ITS-S path that starts at an ITS-S ingress anchor node and ends up at an ITS-S egress
anchor node
3.6
ITS-S capability
uniquely addressable protocol or functionality that is part of an ITS-S Managed Service Entity
Note 1 to entry: Examples of ITS-S capabilities in the ITS station facilities layer are generic ITS-S facilities
layer services specified in ISO/TS 17429 (Communication Profile Handler, Facilities Services Handler, Content
1)
Subscription Handler), the position and time service defined in ISO/TS 21176 , the security service defined
2)
in ISO/TS 21177 ; examples of ITS-S capabilities in the ITS-S networking and transport layer are IPv6
functionalities defined in ISO 21210 (IPv6 neighbour discovery, IPv6 forwarding, IPv6 mobility support, …), the
3)
fast service announcement protocol defined in ISO 22418 , etc.
3.7
ITS-S communication profile
ITS-SCP
parameterized ITS-S communication protocol stack (set of protocols composing all the ITS station
layers) that allows communication end points to communicate with one another
3.8
ITS-S flow
identifiable sequence of packets of a given ITS-S flow type transmitted between a source node and a
destination node
3.9
ITS-S flow identifier
FlowID
identifier, being unique within an ITS station unit, that identifies an ITS-S flow
3.10
ITS-S flow type
set of characteristics describing a data flow
Note 1 to entry: Flow types could be pre-assigned, well known and recorded with some authority registry or
defined by the applications following a number of conventions
3.11
ITS-S flow type identifier
FlowTypeID
identifier being unique within the ITS station that identifies an ITS-S flow type
3.12
ITS-S path
directed sequence of nodes connected by links starting at a source node, traversing a communication
interface of the source ITS-S, an ITS-S ingress anchor node and an ITS-S egress anchor node, ending at a
destination node
Note 1 to entry: In some circumstances, the ITS-S ingress anchor node and the ITS-S egress anchor nodes might
be collapsed with the destination node (i.e. the roles of the ITS-S ingress anchor node and the ITS-S egress anchor
node are played by the destination node).
Note 2 to entry: For bidirectional communications, two such ITS-S paths exist, i.e. one starting at each
communication end point. Note further that there could be multiple ITS-S paths between a source and its
destination.
1) Under development.
2) Under development.
3) To be published.
2 © ISO 2018 – All rights reserved

3.13
ITS-S path identifier
PathID
identifier of a given ITS-S path being unique within an ITS station
3.14
ITS-S managed service entity
MSE
uniquely addressable entity in an ITS-S layer comprised of a set of related ITS-S capabilities
Note 1 to entry: Examples of ITS-S managed service entities are: a communication module in the ITS-S access
technologies layer (M5, cellular, etc.), a protocol suite in the ITS-S networking and transport layer (IPv6, FNTP,
GeoNetworking, 6LoWPAN, etc.), the generic facilities MSE at the ITS-S facilities layer.
3.15
locator
identifier of the topological location of a node in a communication network
Note 1 to entry: A locator of an ITS station is the identifier of an ITS-S ingress anchor node (an ITS station has as
many locators as there are ITS-S ingress anchor nodes to which it is attached).
3.16
registered ITS-S flow
ITS-S flow that has been allocated an ITS-S FlowID
3.17
source node
communication end point that creates packets for transmission to peer entities
4 Symbols and abbreviated terms
[14]
CI Communication Interface, see ISO 21218
ITS-S-FlowID ITS Station Flow Identifier
ITS-S-FlowTypeID ITS Flow Type Identifier
ITS-S ITS station, see ISO 21217:2014
ITS-S-AP ITS Station Application Process
ITS-S-APID ITS Station Application Process Identifier
ITS-SCP ITS station communication profile
[16]
ITS-SCU-CMC ITS-SCU Communication Management Centre, see ISO 24102-2
MSE ITS station Managed Service Entity
PathID ITS station Path Identifier
PFM, pfm Path and Flow Management
SAL ITS Station Access Layer
SFL ITS Station Facilities Layer
SME ITS Station Management Entity
SNTL ITS Station Networking and Transport Layer
[14]
VCI Virtual Communication Interface, see ISO 21218
5 Overview
5.1 Relation with the ITS station reference architecture
This document specifies functionalities of the ITS “Station Management Entity” (SME) of the
communication architecture specified in ISO 21217:2014. The layered ITS station communication
architecture is illustrated in Figure 1 — ITS station reference architecture. The ITS “Station Facilities
Layer” (SFL), the ITS “Station Networking & Transport Layer” (SNTL), and the ITS “Station Access
Layer” (SAL) are each capable of containing multiple managed service entities (ITS-S Managed Service
Entity) running simultaneously as detailed in ISO 21217:2014.
5.2 ITS-S flows
In general, an ITS station supports multiple ITS-S applications of different types such as applications
for road safety, traffic efficiency, value added services and infotainment. Each application that
needs to send and receive data is most often either engaged in a bidirectional exchange with known
communication peers, or is repetitively broadcasting data to unidentified receivers. The nature of the
transmitted information is known and communication requirements are typically specific to the type
of data flow (road safety, traffic efficiency, infotainment). These communication requirements can be
expressed in terms of bandwidth, end-to-end delay, security, packet size, etc. for each type of data flow.
A list of requirements is provided in ISO 17423:2018.
The ITS-S flow type allows the classification of data flows with the same characteristics, transmitted
from distinct ITS stations or to distinct destination nodes. However, in the common situation in which
several applications are installed in a given ITS station unit, these applications are typically engaged in
several data exchanges of distinct nature (different flow types). There could consequently exist multiple
ongoing data flows of different natures, competing for the same ITS station resources.
5.3 ITS-S communication profiles
In general, an ITS station supports multiple protocols and functionalities (ITS-S capabilities) within
each of the ITS station layers: in the ITS-S facilities layer (e.g. the communication handler specified
[24] [25]
in ISO 17423:2018, ITS-S application processes for CAM and DENM ,…), various types of ITS-S
[8] [21] [26]
networking and transport layer protocols (IPv6 , FNTP , GeoNetworking ,…) and various types
[14]
and instances of access technologies (communication interfaces ).
Available protocols and access technologies can be combined in various ways to transfer data to
the destination. A collection of protocols used to transfer data to a destination is referred to as the
communication profile (ITS-SCP).
The communication profile indicates the protocol stack, i.e. the protocols at the ITS station facilities
layer, the ITS station networking and transport layer, and ITS station access technologies layer that are
used for a given data flow.
Several communication profiles could exist to reach a given destination. Some communication profiles
may not be appropriate to reach a given destination if the communication end points do not support a
compatible set of protocols.
4 © ISO 2018 – All rights reserved

5.4 ITS-S paths
An ITS-S path as defined in ISO 21217:2014 starts at its source node and ends up at a destination node.
There may be zero or more intermediate nodes in the ITS-S path between the source node and the
destination node.
However, the ITS-S path towards a destination node goes through “selectable communication nodes”
that are pre-determined according to the peer nodes engaged in the communication. These “selectable
communication nodes” are referred to as the ‘ITS-S anchor nodes’ (respectively the ‘ITS-S ingress anchor
node’ and the ‘ITS-S egress anchor node’) and form the entry and exit end points of a controllable path
segment (‘ITS-S anchor segment’). This is illustrated in Figure 2.
NOTE 1 The CI, the ITS-S ingress anchor node and the ITS-S egress anchor node are the selectable parts
of the path. The CI is the starting point of the ITS-S path. The ITS-S ingress anchor node is the first selectable
communication node on the path to which the packets are forwarded, whereas the egress ITS-S anchor is the last
selectable communication node.
NOTE 2 For groupcast communication, there are multiple destinations but the packets transmitted to a group
are not duplicated before reaching the ITS-S egress anchor node, hence all destination nodes are said to be
reachable over the same path. The ITS-S egress anchor node can play the role of a rendez-vous point for IP-based
multicast communications.
Figure 2 — Overview of the concept of ITS-S path and ITS-S anchor segment
In some circumstances, for example when the source node and the destination node are both located
in the same local network (see ITS-S path 3 in Figure 2), the ingress and ITS-S egress anchor nodes are
collapsed with the destination node.
— For Internet-based communications (see ITS-S path 1 and 2 in Figure 2), an ITS-S path goes through
a communication interface (CI) of the source ITS-S. The ITS-S ingress anchor node is a node in the
access network to which the ITS station is locally attached, and the ITS-S egress anchor node is a node
in the Internet to which the ITS station is remotely attached. It finally reaches its destination node.
— For local ad hoc communications (see ITS-S path 3 in Figure 2), an ITS-S path goes through a CI of
the source ITS-S. The ingress anchor, egress anchor and the destination node are identical.
The diversity of communication interfaces and ITS-S anchor nodes imply a multiplicity of ITS-S paths
may be available to reach a given destination node. This happens:
— When multiple ITS-S ingress anchor nodes are reachable through the same communication
interface, each of them typically located in the access network of distinct operators or located in
different parts of the network when communication traffic is discriminated between road safety,
traffic efficiency and infotainment types of services, or when multiple ITS-S ingress anchor nodes
are reachable through distinct communication interfaces. Note that ITS-S ingress anchor nodes
could be significantly distant in the topology of the communication network (e.g. the ITS-S ingress
anchor node on an ITS-S path going through an 11p communication interface of a vehicle ITS station
is likely on the roadside infrastructure whereas the ITS-S ingress anchor node on an ITS-S path
going through the 3G communication interface is in the network of a cellular operator thus much
further away).
— When a diversity of ITS-S egress anchor nodes from the same service operator are deployed in
distinct geographic areas or when a diversity of ITS-S egress anchor nodes from distinct service
operators provide similar or complementary services.
These ITS-S paths can take very different routes.
5.5 ITS-S capabilities
ITS-S capabilities are used to indicate protocols and functionalities that can be provided by a given ITS-S
managed service entity. Each ITS-S capability provides a well-identified function, with some specific
characteristics. Each ITS-S capabilitiy has a unique identifier. Well-known ITS-S capabilities may be
recorded in a global registry. An ITS-S capability can be provided by several protocols or methods.
At the ITS-S networking and transport layer, examples of ITS-S capabilities in the IPv6 Networking
ITS-S managed service entity (mse-IPv6suite) are the protocols providing network addressing
(IPv6 Stateless Address AutoConfiguration), the protocol providing session continuity (IPv6 mobility
support), the protocol providing encryption (IPsec). These ITS-S capabilities of the IPv6 Networking
MSE are defined in ISO 21210.
ITS-S capabilities of the generic ITS-S managed service entity in the ITS-S facilities layer (mse-
GISFsuite) are specified in ISO 17423:2018 (facilities service handler, content subscription handler,
[7]
communication profile handler), in ISO/TS 21177 [21177] (security service) and ISO/TS 21176
(position and time functionality).
5.6 Path and flow management
When there are multiple ITS-S flows and a diversity of communication profiles and ITS-S paths, it is
useful to determine for each ITS-S flow:
— The most suitable ITS-S communication profile to transfer data to the destination. This determination
is not only necessary for the appropriate use of resources at the sending ITS station, but is also
necessary to ensure both communication end points use a compatible set of protocols.
— The most suitable ITS-S path for routing a given ITS-S flow. This determination is not only necessary
to route the packets but also to map ITS-S flows to the ITS-S path that best meets the communication
requirements of the ITS-S application processes installed on the ITS station.
The determination of the ITS-S path implies the selection of the communication interface, the ITS-S
ingress anchor node and ITS-S egress anchor node as shown in Figure 2.
Such determination is made by the ITS station management entity once it has gathered sufficient
information on the following categories of information:
— Communication requirements of the applications installed on the ITS station that require
communication resources of the ITS station (classified in operational, destination type, performance,
monetary cost, energy cost, security, and protocol requirements as specified in ISO 17423:2018).
6 © ISO 2018 – All rights reserved

— Capabilities of all layers of the ITS station (functionalities, technologies and protocols supported by
the ITS station, characteristics of available communication interfaces, etc.):
[24] [25] [6]
— Supported ITS station facilities layer protocols (CAM , DENM , SPaT, MAP, CoAP ,
communication handler, service announcement, generic message handling, local dynamic
[3]
map ,…) and their parameters;
[21] [8]
— Supported ITS station network & transport layer protocols (UDP, TCP, FNTP , IPv6 ,
[5] [26]
6LowPAN , GeoNetworking/BTP , etc.), the functionalities they provide (broadcasting,
multicasting, geocasting, mobility management, multihoming, etc.) and their parameters;
[13][27][28] [12]
— Supported ITS station access technologies layer protocols (IEEE 802.11(p) , infrared ,
[23] [10] [11] [2] [29]
satellite , 2G /3G , LTE , IEEE 802.15.4 ,…), the functionalities they provide (short
range communication, medium range communication, long range communication, …) and their
parameters;
— Capabilities of the access networks to which the ITS station is attached:
— Network services provided by surrounding neighbour nodes (e.g. vehicle ITS station able to
relay information to other vehicles, roadside ITS station providing Internet connectivity, etc.).
The ITS station detects neighbour ITS stations and other legacy nodes through network services
(neighbour discovery and other mechanisms including signalling protocols) and facilities
services (CAM, DENM, SPaT, MAP, SAM, …). For instance, among the services of neighbour ITS
stations detected from network layer signalling protocols, a neighbour ITS station may provide
a network access service allowing the ITS station to access the Internet while another may
provide an anchor service;
— Current network conditions: various metrics of an access technology (bandwidth, packet loss),
status of link (set up, in use, .), network load, reachability over that link (availability of Internet
access);
— Capabilities of the peer communication end points as they must be able to support the same
communication profiles;
— Capabilities of the ITS-S anchor nodes along the ITS-S path;
— Regulations and policies including local, national and regional rules (e.g. allowed access technologies
and their transmission power; location privacy) and stakeholder rules (e.g. always prefer one access
technology over another).
Figure 3 illustrates the architectural components (building blocks and management data flows) of
the ITS station management entity which are involved in the ITS-S path selection process. The same
architecture applies to the communication profile selection process introduced in ISO 17423:2018.
Figure 3 — Architecture of the communication profile and path selection [ISO 21217:2014]
NOTE In general, it cannot be ensured that the communication requirements will be met all along a
particular ITS-S path as there can be no knowledge of the capabilities of all the nodes along the ITS-S path.
5.7 ITS station management functionalities
This document defines the following functionalities of the ITS “Station Management Entity” (SME) to
determine available ITS-S paths and select the most appropriate one for each ITS-S flow.
— ITS station capabilities management is the process of ascertaining the capabilities of the ITS
station (supported protocols or services and their functions, available communication interfaces
and their characteristics) and which of them can be used at a given time.
— Path management is the process of determining ITS-S paths where packets can be routed. To do
so, the SME must collect information from the ITS-S layers. In particular, it must determine the
neighbour network nodes that could act as ITS-S ingress anchor nodes, their capabilities and the
network services they provide (e.g. Internet access).
— Flow management is the process of keeping track of the ITS-S flows in the ITS station, including
assigning and releasing the ITS-S flow identifiers.
— Path selection is the process of determining the most appropriate ITS-S path(s) from all the ITS-S
paths available for a given ITS-S flow or a set of ITS-S flows of the same characteristics.
— Communication profile selection is the process of determining the most appropriate protocol stack
for an ITS-S flow.
In order to determine the most appropriate ITS-S path for a given ITS-S flow, the SME must first have the
most up-to-date view of all the available ITS-S paths and for how long they are able to survive. Keeping
track of the available ITS-S paths requires gathering information from all ITS-S layers and maintaining
accurate information.
The SME thus collects information from all the ITS-S layers and monitors the current state of the
network (via the MN-SAP), the characteristics of the access technologies (via the MI-SAP), flow
8 © ISO 2018 – All rights reserved

requirements expressed by applications (via the MA-SAP) or the facilities (via the MF-SAP), and other
information maintained locally in order to determine routing policies to be applied to ITS-S flows, given
the flow requirements, the current status of the network and access technologies characteristics.
Once the determination is realized, the SME provides to all ITS-S layers the communication profile(s)
(ITS-SCP) and the rules to be applied to a given ITS-S flow or set of ITS-S flows. This information can be
updated dynamically.
NOTE The rationale for those functionalities is detailed in the deliverable D2.4 Final System Specification of
[30]
the ITSSv6 project from which this document is largely derived.
5.8 ITS station management information tables
The SME collects and maintains information about ITS-S flows, ITS-S paths and ITS-S capabilities. This
information can be maintained in the form of tables as illustrated on Figure 4.
Parameters obtained through the M*-SAP are expressed to the SME in a protocol agnostic fashion so
that mechanisms for path and flow management are performed identically and independently of the
type of ITS station (vehicle, roadside, personal or central ITS stations), its capabilities (protocols and
functionalities) and the type of implementation (distributed in several ITS-SCU or not).
Figure 4 — Information maintained within the ITS station management entity
5.9 Interaction with ITS station layers
The interaction between the ITS “Station Management Entity” (SME) and the layers of the ITS station
architecture, the ITS station application entity and the ITS station security entity is made through the
management Service Access Points (SAP) of the ITS station (MI-SAP, MN-SAP, MF-SAP, MA-SAP, MS-SAP)
[17]
specified in ISO 21217:2014 and in ISO 24102-3 as follows.
— The interactions between the SME and ITS station application processes (ITS-S-APs) are realized
through the MA-SAP using the MA-REQUEST service initiated by the ITS-S-APs, and the MA-
[17]
COMMAND service initiated by the SME. These service primitives are specified in ISO 24102-3 .
ISO 17423:2018 and ISO/TS 17429:2017 specify how related service primitive functions are handled
by the ITS-S-APs.
— The interactions between the SME and the ITS “Station Facilities Layer” (SFL) are realized
through the MF-SAP using the MF-REQUEST service initiated by the SFL to the SME and the MF-
COMMAND service initiated by the SME. The request and confirm service primitives are specified
[17]
in ISO 24102-3 . ISO/TS 17429:2017 specifies how related service primitive functions are handled
by the generic ITS-S managed service entity (mse-GISFsuite) of the SFL.
— The interactions between the SME and the ITS “Station Networking & Transport Layer” (SNTL) are
realized through the MN-SAP using the MN-REQUEST service initiated by the SNTL, and the MN-
COMMAND service initiated by the SME. The request and confirm service primitives are specified
[17] [8]
in ISO 24102-3 . ISO 21210 specifies how related service primitive functions are handled
by the IPv6 Networking ITS-S Managed Service Entity of the SNTL (mse-IPv6suite) whereas
[22]
ISO 29281-1 specifies how related service primitive functions are handled by the FNTP ITS-S
Managed Service Entity of the SNTL (mse-FNTPsuite).
[8] [9]
NOTE ISO 21210 is intended to be revised as Part 1 of a multi-part standard on IPv6.
— The interactions between the SME and the ITS “Station Access Layer” (SAL) are realized via the MI-
SAP using the MI-REQUEST service initiated by the SAL, and the MI-COMMAND service initiated by
[17] [14]
the SME. The request and confirm service primitives are specified in ISO 24102-3 . ISO 21218
[15]
and ISO 24102-1 specify how related service primitives are handled by Communication Interface
ITS-S Managed Service Entity of the SAL (mse-CIsuite).
Figure 5 shows the information flow between the SME and the ITS station layers.
10 © ISO 2018 – All rights reserved

Figure 5 — Cross-layer information flow for path and flow management
6 Requirements for flow management and communication profile selection
6.1 ITS-S flow type parameters
Table 1 presents the list of parameters that are maintained by the SME for each ITS-S flow type known
within the ITS-S. The method used to record ITS-S flow type information is implementation specific and
is out of scope of this document. The parameters presented in Table 1 shall be of ASN.1 types specified
in the normative Annex D.
Each ITS-S flow type is identified by an ITS-S flow type identifier (ITS-FlowTypeID) which shall be
unique in the ITS station. Well-known flow types may be identified by a globally unique ITS-FlowTypeID
assigned by a registry.
Table 1 — ITS-S flow type parameters maintained by the SME
ITS-S flow type parameters ASN.1 type Description
ITSsapiid
IITS-S-APID (key) Identifier of an ITS-S application process (exactly one of
possibly several instances of it in an ITS-SU). Originally
[15]
specified in ISO 24102-1 with name ApplicationID;
[1]
now specified in ISO 17419 .
[1]
ITS-SapSsId
ITS-S RX/TX interface (key) Sink or source of an ITS-S-AP. Specified in ISO 17419 .
FlowTypeID
ITS-FlowTypeID Identifier of the ITS-S flow type (if larger than 0,
corresponds to a well-known ITS-S flow type which
parameters are recorded in a registry). Specified in
[1]
ISO 17419 .
UserPriority
Priority Requested priority to be applied to this ITS-S flow type.
[1]
Specified in ISO 17419 .
ServSecu CapaInfos List of security services (ITS-S capabilities) to be
applied to packets of this ITS-S flow type. Necessary
atomic operations are performed by the ITS station
security entity
(DataConfidentiality, DataIntegrity,
NonRepudiation, SourceAuthentication,
LocationPrivacy).
CapaInfos
ServFac List of ITS station facilities layer services (ITS-S
capabilities) to be applied to packets of this ITS-S flow
type once or on a per packet basis.
CapaInfos
ServCom List of ITS communication services (ITS-S capabilities)
to be applied to packet of this ITS-S flow type once or
on a per packet basis. (ContConnect, NxRepeat, etc.).
PortNumber
RcvPort Specific port requested by the ITS-S-AP to receive
DestinationType
DstType/ Type of transmission (single receiver, group of receivers
CommunicationMode (multicast, broadcast), geographic area, etc.)
DestDomain
DstDomain Domain of communication (ITS-S internal, local, Internet)
CommDistRequested MinCommDistance Minimum distance in meter to reach the next neighbour
node. Specified in ISO 17423:2018.
Directivity
Directivity Information a
...