oSIST prEN ISO 22418:2019

SLOVENSKI STANDARD
01-februar-2019
Inteligentni transportni sistemi - Protokol objave hitre storitve (FSAP) (ISO
22418:2018)
Intelligent transport systems - Fast service announcement protocol (FSAP) (ISO
22418:2018)
Systèmes de transport intelligents - Protocole d'annonce de service rapide (FSAP) (ISO
22418:2018)
Ta slovenski standard je istoveten z: prEN ISO 22418
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.

INTERNATIONAL ISO
STANDARD 22418
First edition
2018-06
Intelligent transport systems — Fast
service announcement protocol (FSAP)
Systèmes de transport intelligents — Protocole d'annonce de service
rapide (FSAP)
Reference number
ISO 22418:2018(E)
©
ISO 2018
ISO 22418:2018(E)
© ISO 2018
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Published in Switzerland
ii © ISO 2018 – All rights reserved

ISO 22418:2018(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 General requirements . 2
6 Architecture . 4
6.1 ITS communications architecture . 4
6.2 Implementation architecture . 4
6.3 Communication roles and entities . 4
6.4 Communication phases . 5
6.4.1 Overview . 5
6.4.2 Service initialization phase . 5
6.4.3 Service operation phase . 8
6.5 Advertised services . 8
6.6 FSAP reference architecture . 9
7 Protocol elements .10
7.1 Management service access points .10
7.2 Protocol data units .10
7.2.1 General.10
7.2.2 Fast service advertisement message .11
7.2.3 Fast service response message .11
7.2.4 Secured messages .11
7.2.5 Request and response messages .12
7.3 Port numbers .12
7.4 ITS application object identifier . .12
8 Protocol procedures .12
8.1 General .12
8.1.1 FSAP communication handler procedures .12
8.1.2 FSAP manager procedures .13
8.1.3 Extension elements .13
8.2 Service provider .14
8.2.1 FSAP registration .14
8.2.2 FSAP registration update .15
8.2.3 FSAP deregistration . .17
8.2.4 FSAP communication management.18
8.2.5 Transmission of FSAM . . .21
8.2.6 Reception of FSRM .21
8.3 Service user .24
8.3.1 FSAP registration .24
8.3.2 FSAP registration update .25
8.3.3 FSAP deregistration . .25
8.3.4 Reception of FSAM .26
8.4 Service operation phase .30
8.5 ITS station-internal management communications .31
8.6 Duplicate service detection .31
8.7 System Service .31
8.7.1 General.31
8.7.2 Mandatory applications .31
9 Optionally supported features .32
ISO 22418:2018(E)
10 Conformance .32
11 Test methods .32
Annex A (normative) ASN.1 modules .33
Annex B (normative) Support of application requirements for communications.41
Annex C (normative) Support of path and flow management .43
Annex D (normative) Implementation conformance statement .44
Bibliography .55
iv © ISO 2018 – All rights reserved

ISO 22418:2018(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 first edition cancels and replaces ISO 24102-5:2013 which has been technically revised.
ISO 22418:2018(E)
Introduction
Provisioning of ITS services at specific locations on the road network requires awareness of the
availability and the purpose of such services in order to allow a road network user deciding on the
potential consumption of such a service. Awareness of services can be achieved by pull and push
mechanisms. Whilst pull mechanisms are well understood and deployed for non-time-critical usage,
several use cases depend on a push mechanism. Whilst pull mechanisms require a-priori knowledge
of an intended service, push mechanisms support also "mandatory services" that may be locally and
dynamically applicable and defined by local policies rather than global regulations.
This document illustrates and specifies the features of the cooperative push mechanism "Service
Advertisement" based on the internationally harmonized message format specified in ISO/
TS 16460:2016, and builds on top of any localized communications protocol stack.
[3]
WAVE service advertisement (WSA) specified in IEEE 1609.3 is interoperable with the service
advertisement specified in this document. However this document supports more features from ISO/
TS 16460:2016 than WSA does.
Understanding service advertisement and the related protocol specified in this document requires
understanding of ISO/TS 16460:2016.
Requirements are specified in the following clauses of this document.
— Clause 5 specifies general requirements.
— Clause 6 presents a tutorial on architectural issues related to FSAP.
— Clause 7 specifies protocol elements of FSAP.
— Clause 8 specifies protocol procedures of FSAP.
— Clause 9 specifies conformance declaration.
— Clause 10 specifies test methods.
— Annex A specifies the ASN.1 module for FSAP.
— Annex B specifies details of the optional support of presenting communication requirements of
FSAP to the ITS station management compliant with ISO 17423:2018.
— Annex C specifies details of the optional support of path and flow management for FSAP compliant
with ISO 24102-6:2018.
— Annex D presents the implementation conformance statement proforma.
vi © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 22418:2018(E)
Intelligent transport systems — Fast service
announcement protocol (FSAP)
1 Scope
This document specifies the "Fast Service Announcement Protocol" (FSAP).
FSAP is in support of locally advertised ITS services uniquely identified by an ITS application identifier
(ITS-AID).
This document specifies message formats and related basic protocol procedures by reference to ISO/
TS 16460:2016, and further related protocol requirements for operation of FSAP in the context of an
ITS station specified in ISO 21217:2014.
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/IEC 8825-2, Information technology — ASN.1 encoding rules — Part 2: Specification of Packed
Encoding Rules (PER) — Part 2
ISO/IEC 8825-7, Information technology — ASN.1 encoding rules — Part 7: Specification of Octet Encoding
Rules (OER)
ISO/TS 16460:2016, Intelligent transport systems — Communications access for land mobiles (CALM) —
Communication protocol messages for global usage
ISO 17419, Intelligent Transport Systems — Cooperative ITS — Globally unique identification
ISO 17423:2018, Intelligent Transport Systems — Cooperative ITS — Application requirements for selection
of communication profiles
ISO 21217:2014, Intelligent transport systems — Communications access for land mobiles (CALM) —
Architecture
ISO 21218, Intelligent Transport Systems — Hybrid communications — Access technology support
ISO 24102-3, Intelligent Transport Systems — ITS station management — Part3: Service access points
ISO 24102-4, Intelligent Transport Systems — ITS station management — Part 4: Station-internal
management communications
ISO 24102-6:2018, Intelligent Transport Systems — ITS station management — Part 6: Path and flow
management
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21217:2014 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
ISO 22418:2018(E)
4 Symbols and abbreviated terms
FSAM Fast service advertisement message
FSAP Fast service announcement protocol
FSRM Fast service response message
REQN Request message PDU, no response message PDU expected
REQRES Request or response message PDU out of the set REQW, REQN, RES
REQW Request message PDU, response message PDU expected
RES Response message PDU, acknowledging a REQW
S-FSAM Secured FSAM
S-FSRM Secured FSRM
SrvIniP Service initialization phase
SrvOpP Service operation phase
5 General requirements
The normative part of the specification of the "Service Advertisement messages" in ISO/TS 16460:2016
is a normative part of this document.
The "Fast Service Announcement Protocol" (FSAP) specified in this document shall be identified in
FSAP application protocol data units (APDUs) by the version number three.
APDUs specified in this document are the "Fast Service Advertisement Message" (FSAM) and the "Fast
Service Response Message" (FSRM).
The messages FSAM and FSRM shall be encapsulated by a security frame, resulting in a Secured FSAM
(S-FSAM) and a Secured FSRM (S-FSRM).
Fragmented transmission of FSRMs and FSAMs is prohibited, thus the maximum size of S-FSAMs and
S-FSRMs is limited by the capabilities of the protocol stack used for transmission.
FSAP is identified at the ITS-S networking & transport layer by
— the well-known registered ITS port number (ITS-PN) PORT_SAM = 1 = 0x00.01 published on [10],
identifying the FSAP port that is receiving groupcasted S-FSAMs, and
— dynamically assigned ITS-PNs:
— PORT_DYN_FSAM identifying the FSAP port that is receiving unicast S-FSAMs. The dynamic
assignment is done in the ITS-SU that is transmitting S-FSRMs;
— PORT_DYN_FSRM identifying the FSAP port that is receiving unicast S-FSRMs. The dynamic
assignment is done in the ITS-SU that is transmitting S-FSAMs;
as illustrated in Table 1; see also 7.3 on ITS port numbers.
2 © ISO 2018 – All rights reserved

ISO 22418:2018(E)
Table 1 — FSAP ITS port numbers
Direction Source ITS-PN Destination ITS-PN MAC mode
From service adver- PORT_DYN_FSRM PORT_SAM Groupcast
tiser to service user (broadcast or multicast)
PORT_DYN_FSAM Unicast
From service user PORT_SAM PORT_DYN_FSRM
to service adver-
PORT_DYN_FSAM
tiser
NOTE Procedures on how to perform multicast transmission of S-FSAMs are not specified in this document.
Unicast transmissions of S-FSRMs and S-FSAMs may be repeated, e.g. after timeout for a respective
acknowledgement, as defined by implementation.
Further on the FSAP is identified by
— the ITS application identifier (ITS-AID) 2.113.664 published on [10]; see also 7.4. The p-encoded
(ASN.1 unaligned packed encoding rules) presentation of this number of ASN.1 type ITSaid
specified in ISO 17419 is 0pE0.00.00.00, i.e. fits into a four octet field.
An implementation supporting path and flow management shall be compliant with ISO 24102-6:2018.
An implementation for a distributed ITS-SU, i.e. an ITS-SU consisting of several ITS-SCUs interconnected
with an ITS station-internal network, shall be compliant with ISO 24102-4.
As
[2]
— identical message formats for service advertisement are used in IEEE 1609.3 (WAVE SAM) and
[16]
ETSI TS 102 890 (ESAM), and
[2] [16]
— the features specifications in IEEE 1609.3 and ETSI TS 102 890 are sub-sets of the specification
in this document,
an implementation of FSAP optionally may support the service advertisement from IEEE WAVE devices
and the service announcement from ETSI ITS stations by considering the following:
— WAVE SAM support
[4]
1) The only supported access technology is IEEE 802.11 OCB mode specified in IEEE 802.11
[6]
(ISO 21215 with US frequency allocation and WAVE-specific details).
2) The only networking & transport layer protocol supported is the WAVE Short Message protocol
[2]
(WSMP) specified in IEEE 1609.3 , which uses the same message format as FNTP with TPID-
[8]
FS zero .
3) Port numbers are not used. Instead, the service advertisement message SAM is identified by
the value 135 of ITS-AID, used as a transport layer destination address in WSMP (i.e. in FNTP
[8]
with TPID-FS zero ).
4) The WAVE SAM is identical to FSAM.
5) S-FSAM (Security encapsulated FSAM) uses the same format and encoding as WAVE does.
[3]
WAVE security is specified in IEEE 1609.2 .
6) FSRM and other features, e.g. mandatory applications and private service channels, are not
supported.
— ESAM support
[6]
1) The only supported access technology is IEEE 802.11 OCB mode (ISO 21215 with EU
frequency allocation and ETSI-specific details).
ISO 22418:2018(E)
2) The only networking & transport layer protocol currently supported is ETSI GeoNetworking/
ETSI Basic Transport Protocol.
3) The ESAM is identified by the BTP port number for SAM specified in ETSI TS 103 248.
4) The ESAM is identical to FSAM except that ESAM is preceded by the ETSI common message
header.
5) Security encapsulation is not specified.
6) FSRM and other features, e.g. mandatory applications and private service channels, are not
supported.
6 Architecture
6.1 ITS communications architecture
The "FAST Service Announcement Protocol" (FSAP) is designed as a functionality of the ITS station and
communication architecture specified in ISO 21217:2014.
6.2 Implementation architecture
The "Fast Service Announcement Protocol" (FSAP) specified in this document supports the
implementation architectures introduced in ISO 21217:2014.
6.3 Communication roles and entities
The "FAST Service Announcement Protocol" (FSAP) distinguishes the following roles identified in ISO/
TS 16460:2016:
a) Service Advertiser:
— Management of advertisement requests from Service Providers
— Transmission of FSAMs and reception of FSRMs
b) Service Provider:
— Provision of ITS services
c) Service User:
— Reception of FSAMs and transmission of FSRMs
— Consumption of ITS services
An ITS-SU may simultaneously or sequentially act as a service advertiser, service provider, and
service user.
This document does not explicitly consider the distinction of service advertiser ITS-SUs and service
provider ITS-SUs; for the purpose here the two roles are assumed to be located in the same ITS-SU.
An instance of any kind of ITS station identified in ISO 21217:2014 (roadside, vehicle, portable, centre)
may implement the FSAP.
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ISO 22418:2018(E)
6.4 Communication phases
6.4.1 Overview
In order to allow an ITS-SU to offer an ITS service to another ITS-SU by means of an application
session, a service initialization phase (SrvIniP) is performed by the FSAP, where the SrvIniP is based
on localized communication, e.g. applying the FNTP networking & transport layer protocol specified in
[8]
ISO 29281-1 .
After initialization, the application session is performed during the service operation phase (SrvOpP),
where the SrvOpP may be based on either localized communication or networking, e.g. IPv6
communication, over any kind of access technology.
During SrvIniP, handover to another protocol stack, e.g. another access technology and IPv6, may be
demanded.
The real-time SrvIniP procedures preferably are implemented in an ITS-S router.
NOTE The specification of SrvOpP is outside the scope of this document.
6.4.2 Service initialization phase
The purpose of SrvIniP is to invite a peer ITS-SU by means of a "Fast Service Announcement Message"
(FSAM) to use an ITS service which is uniquely identified by an ITS application identifier (ITS-AID)
specified in ISO 17419; ITS-AID points to an ITS application object.
NOTE 1 Usage of some allocated ITS-AID values may not be meaningful in FSAM.
Acceptance of such an invitation typically results in a session, where the two peer ITS-S applications
exchange data. However, a session is not necessarily needed, i.e. the service may be provided completely
by the FSAM. Thus FSAM provides also the means to periodically broadcast information from ITS
broadcast services.
Three operational options of SrvIniP are specified. The distinction originally was motivated by the two
ITS application objects
[1]
1) ITS application class and
2) ITS application,
and was extended
3) to allocate private communication channels to individual ITS station units (ITS-SUs).
[1]
Option one, originally designed for ITS application classes (DSRC-like SrvIniP) , is illustrated in
Figure 1. FSAM is sent by a service advertiser ITS station to invite for a service initialization phase.
FSRM is sent by a service user ITS station to acknowledge FSAM. Successful SrvIniP is given by the first
successful REQW or REQN of the service provider.
NOTE 2 In [1], BST corresponds functionally to FSAM, and VST corresponds functionally to FSRM.
ISO 22418:2018(E)
Figure 1 — ITS application session with FSRM
NOTE 3 The concept of application classes was introduced in [1]. Distinction of classes was done with an
identifier of ASN.1 type DSRCapplicationEntityID. The difference between an ITS application class and an
ITS application is, that for an ITS application class several contexts exist. Each context itself can be referred to as
an ITS application.
During a SrvOpP
— requests, either with or without an expected response, typically are sent by the service provider,
but may also be sent by the service user, and
— responses typically are sent by the service user, but may also be sent by the service provider,
dependent on the specification of the ITS application.
NOTE 4 Rules on which data are sent by a service provider or by a service user apply strictly for [1]. In general,
for ITS there are no such rules.
NOTE 5 As specified in ISO 21217:2014, the service user and service client instances of an ITS application are
referred to as ITS-S application processes; ITS-S application processes residing in the "Applications" entity are
referred to as ITS-S applications.
[2]
Option two, originally designed for ITS applications (WAVE-like SrvIniP) , is illustrated in Figure 2.
FSAM is sent by a service advertiser to perform service initialization. Successful SrvIniP is given by the
first successful REQW or REQN of the service user.
6 © ISO 2018 – All rights reserved

ISO 22418:2018(E)
Figure 2 — ITS application session without FSRM
During a SrvOpP
— requests, either with or without an expected response, typically are sent by the service user, but
may also be sent by the service provider, and
— responses typically are sent by the service provider, but may also be sent by the service user,
dependent on the specification of the ITS application.
NOTE 6 In general for ITS there is no such strict rule which station type is sending which type of message.
Option three presents the situation when a service advertiser wants to allocate private communication
channels to service users. In this option an additional handshake between the service advertiser and
the service user is needed prior to start of the SrvOpP. The option three is applicable for ITS applications
and ITS application classes.
NOTE 7 "Private communication channel" does not necessarily mean that only a single service user station
operates on it. It is up to the service advertiser station to allocate a private communication channel to one or
several service user stations.
ISO 22418:2018(E)
Figure 3 — ITS application session with privately allocated communication channel
6.4.3 Service operation phase
Management of reception and transmission of session messages, e.g.
— "Request with No response expected" (REQN),
— "Request With response expected" (REQW),
— "Response to a request" (RES)
as illustrated in Figures 1, 2, and 3 is outside the scope of this document.
6.5 Advertised services
ITS services being advertised with FSAP are provided by ITS applications which typically are specified
with two complementary ITS-S application processes, e.g. one implementing the provider part, the
other implementing the user part; see ISO 21217:2014.
An ITS application is uniquely identified by an ITS-AID specified in ISO 17419. The one or several
ITS-S application processes of such a single ITS application are distinguished by means of the ITS-S
application process identifier (ITS-SAPID) specified in ISO 17419. Thus a specific ITS-S application
process is uniquely identified by the tuple {ITS-AID, ITS-SAPID}.
ITS-SAPIDs can also be used to distinguish different versions of the ITS-S application process.
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ISO 22418:2018(E)
In order to identify and execute the proper ITS-S application processes during the SrvOpP, two
approaches are identified:
a) management by FSAP;
b) management by the ITS application not using specific features of FSAP.
The approach a) defines in general an ITS application as an ITS application class, i.e. an ITS application
with different contexts; see ISO 17419. Thus upon reception of an FSAM advertising such an ITS
application class, the service user station first will reply with an FSRM presenting the supported ITS-
SAPID values. Based on this information, the service provider will select a suited ITS-S application
process identified by the ITS-SAPID, if possible, or will not be able to provide the service.
A possible procedure b) would be to use version numbers in the APDUs of the ITS-S application
processes, allowing a receiving entity to select the appropriate protocol.
6.6 FSAP reference architecture
The FSAP reference architecture is illustrated in Figure 4.
Figure 4 — FSAP reference architecture
The FSAP is specified by means of two functional entities located in the ITS station, see
ISO 21217:2014, i.e.
— "FSAP communication handler" located in the ITS-S facilities layer;
— "FSAP manager" located in the ITS-S management entity.
ISO 22418:2018(E)
Security services in support of FSAP are located in the ITS-S security entity shown in Figure 4. Related
specifications, except very general ones in 7.2.4, are out of scope of this document.
Further support functionalities are
— protocol stack selection, e.g. as specified in ISO 17423:2018 and ISO 24102-6:2018;
— station-internal management communications, e.g. as specified in ISO 24102-4.
NOTE There are initial investigations in ISO TC204 to provide the functionality of the FSAP Communication
[9]
Handler as part of an ITS station capability defined in ISO TS 17429 .
7 Protocol elements
7.1 Management service access points
NOTE SAPs are functional descriptions which in many cases are not implemented as observable interfaces.
Thus in general SAPs are not testable. The requirements set up in this document with respect of SAPs thus just
mean the functional behaviour rather than a specific implementation. As far as related ASN.1 definitions are
given, these become mandatory as soon as the defined elements become observable, e.g. within PDUs for ITS
station-internal management communications specified in ISO 24102-4.
FSAP uses functionality of the MA-SAP, MF-SAP, and SF-SAP. This functionality is provided by means
of procedures with parameters presented in Tables. Appropriate ASN.1 type definitions implementing
this functionality are specified.
7.2 Protocol data units
7.2.1 General
The format of FSAM shall be identical to the format of SAM specified in ISO/TS 16460:2016; it is
presented in Figure 5.
Figure 5 — General format of FSAM
The format of FSRM shall be identical to the format of SRM specified in ISO/TS 16460:2016; it is
presented in Figure 6.
Figure 6 — General format of FSRM
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ISO 22418:2018(E)
None of the features specified in ISO/TS 16460:2016 are prohibited for FSAM and FSRM.
7.2.2 Fast service advertisement message
The "Fast Service Advertisement Message" (FSAM) is of ASN.1 type Fsam specified in A.2. It is identical
to the service advertisement message SAM of ASN.1 type Sam specified in ISO/TS 16460:2016.
7.2.3 Fast service response message
The "Fast Service Response Message" (FSRM) is of ASN.1 type Fsrm specified in A.2. It is identical to
the service response message SRM of ASN.1 type Srm specified in ISO/TS 16460:2016.
7.2.4 Secured messages
The messages FSAM and FSRM shall be encapsulated by a security frame, resulting in a Secured FSAM
(S-FSAM) and a Secured FSRM (S-FSRM) as presented in Figure 7.
Figure 7 — Encapsulated FSAM and FSRM
Basic requirements are specified in ISO/TS 16460:2016.
The "Secured message" in Figure 7 is specified with the following ASN.1 code, applying octet encoding
rules (OER) specified in ISO/IEC 8825-7:
Smessage ::= SEQUENCE {
protocolVersion  INTEGER (0.255), -- actual version value is three
content      SmessageContent
}
SmessageContent ::= CHOICE {
unsecuredData      OCTET STRING, -- contains unmodified FSAM or FSRM
signedData     SignedData,
encryptedData   EncryptedData,
...
}
Currently identified values of the "Security Option Selector" are:
— 0x80: Unsecured message.
The optional security header and security trailer are not present. The body contains the unmodified
FSAM or FSRM preceded by a length field indicating the number of octets contained in FSAM and
FSRM, respectively.
— 0x81: Signed message.
The optional security header and trailer are present. The body contains the unmodified FSAM or
FSRM preceded by a length field indicating the number of octets contained in FSAM and FSRM,
respectively.
ISO 22418:2018(E)
— 0x82: Encrypted message.
The optional security header and trailer are present. The body contains encrypted data.
[3]
Different methods to sign or encrypt messages are possible. One approach is specified in IEEE 1609.2
with Smessage ::= Ieee1609Dot2Data.
FSAP uses the services of the ITS-S Security Entity for signing and encrypting messages.
Further security details are out of scope of this document.
7.2.5 Request and response messages
Request and response messages may be exchanged between peer ITS-S units within SrvOpP.
NOTE Details are outside the scope of this document.
7.3 Port numbers
FSAP uses an ITS-S network & transport layer protocol, where ITS port numbers (ITS-PNs) are used to
identify source and destination endpoints in an ITS station. ITS-PNs are of ASN.1 type PortNumber
specified in ISO f.
Source and destination endpoints of ITS-S applications, i.e. peer instances of ITS applications,
advertised with FSAP are accessible either with static (well-known) port numbers, or with dynamically
assigned port numbers according to the rules of the ITS-S networking & transport layer protocol and
the protocol procedures specified in this document. The number range of dynamically assigned port
numbers PORT_DYN, and assigned values of static port numbers PORT_REG are identified in ISO 17419
[10]
and published on the ISO Standards Maintenance Portal .
7.4 ITS application object identifier
ITS application objects are identified by means of an "ITS Application object Identifier" (ITS-AID)
specified in ISO 17419. ITS-AID is of ASN.1 type ITSaid. Assigned numbers are published on the ISO
[10]
Standards Maintenance Portal .
8 Protocol procedures
8.1 General
8.1.1 FSAP communication handler procedures
The FSAP communication handler located in the ITS-S facilities layer shown in Figure 4 performs the
following tasks:
— Cooperate with the FSAP manager located in the ITS-S management entity via the MF-SAP as
illustrated in Figure 1, using MF-Commands and MF-Requests specified in ISO 24102-3 with details
specified in this document. The purposes are:
— Receive registering, updating and deregistering requests from the FSAP manager for FSAM
real-time groupcasting;
— Receive requests from the FSAP manager for sending FSAMs and FSRMs in unicast mode to
identified peer stations;
— Forward received FSAMs and FSRMs from peer stations to the FSAP manager, and perform
appropriate procedures.
— Prepare necessary ITS-S networking & transport layer protocols for communication.
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ISO 22418:2018(E)
— Assemble and maintain FSAM PDUs and FSRM PDUs.
— Involve the FSAP security support located in the ITS-S security entity via the SF-SAP illustrated in
Figure 1, using SF-Commands and SF-Requests specified in ISO 24102-3 with details specified in
other standards or specification documents, for:
— converting FSAM PDUs into S-FSAM PDUs, and FSRM PDUs into S-FSRM PDUs;
— converting S-FSAM PDUs into FSAM PDUs, and S-FSRM PDUs into FSRM PDUs.
— Request transmission of S-FSAM PDUs and S-FSRM PDUs via the proper lower communications
protocol stack accessible via the NF-SAP.
— Receive S-FSAM PDUs and S-FSRM PDUs from the proper lower communications protocol stack via
the NF-SAP.
Details are given by dedicated procedures specified in this document.
8.1.2 FSAP manager procedures
The FSAP manager located in the ITS-S management entity shown in Figure 4 performs the
following tasks:
— Cooperate with ITS-S application objects via the MA-SAP as illustrated in Figure 1, using MA-
Commands and MA-Requests specified in ISO 24102-3.
— Register and deregister ITS-S application processes as service providers or service users, and
maintain such registrations.
— Notify registered ITS-S application processes about events of the FSAP. Details depend on the
role as service provider or service user.
— Cooperate with the FSAP communication handler, see 8.1.1.
— Manage forwarding of FSAP related information between ITS-SCUs of the same ITS station applying
ITS station-internal management communications specified in ISO 24102-4, if applicable.
— Contribute to the management of selecting communication protocol stacks for ITS-S applications,
[7]
e.g. specified in ISO 24102-1 , ISO 17423:2018, ISO 24102-6:2018.
Details are given by dedicated procedures specified in this document.
8.1.3 Extension elements
Processing of extension elements contained in FSAMs and FSRMs, if applicable, shall be as specified
in ISO/TS 16460:2016 and in this document. Details of management of some "Extension elements"
specified in ISO/TS 16460 may depend on implementations.
Applicable extension elements identified so far are:
a) SAM extensions listed in ISO/TS 16460:2016, Table 5;
— The extended channel info segment extension shall be supported by FSAP for implementations
(ITS-SUs) supporting hybrid communications.
[2]
NOTE The extended channel info segment extension is not supported in IEEE 1609.3 .
b) Service info extensions listed in ISO/TS 16460:2016, Table 7;
— The SAM application data extension shall be supported by FSAP.
— The SrvOpP Protocol Stack extension of ASN.1 type SrvOpP-ProtocolStack specified in A.4
shall be supported by FSAP for implementations (ITS-SUs) supporting hybrid communications.
ISO 22418:2018(E)
[2]
NOTE The SAM application data extension is not supported in IEEE 1609.3 .
c) Channel info extensions listed in ISO/TS 16460:2016, Table 8;
d) IPv6 routing extensions listed in ISO/TS 16460:2016, Table 9.
8.2 Service provider
8.2.1 FSAP registration
For the purpose of registering its offered service at the FSAP manager, a service provider ITS-S
application process shall use the services of the FSAP manager. The registration data are presented
in Table 2. The appropriate MA-REQUEST.request service primitive function is of ASN.1 type
FsapProviderRegistration specified in A.2. The appropriate MA-REQUEST.confirm service
primitive function is of ASN.1 type FsapProviderRegistrationConf specified in A.2.
Table 2 — Registration at FSAP service provider
Direction Parameter / ASN.1 type Purpose
From service Application identifier / ITSsapiid Identifier uniquely identifying the ITS-S ap-
provider ITS-S ap- plication process providing the service to be
plication process announced in an FSAM. The essential part of
to FSAP manager this application identifier is the ITS-AID that
may be accompan
...