Intelligent transport systems -- Fast service announcement protocol (FSAP)

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.

Systèmes de transport intelligents -- Protocole d'annonce de service rapide (FSAP)

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Status
Replaced
Publication Date
30-May-2018
Withdrawal Date
30-May-2018
Current Stage
9599 - Withdrawal of International Standard
Completion Date
31-May-2018
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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
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ISO 22418:2018(E)
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© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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Published in Switzerland
ii © ISO 2018 – All rights reserved
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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

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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
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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 2018 – All rights reserved v
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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
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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 2018 – All rights reserved 1
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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.
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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.
[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).
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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 2018 – All rights reserved 5
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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
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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 pr
...

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