ISO 29281-1:2013

INTERNATIONAL ISO
STANDARD 29281-1
First edition
2013-04-15
Intelligent transport systems —
Communication access for land mobiles
(CALM) — Non-IP networking —
Part 1:
Fast networking & transport layer
protocol (FNTP)
Systèmes intelligents de transport — Accès aux communications des
services mobiles terrestres (CALM) — Réseautique non-IP —
Partie 1: Réseautique rapide et protocole de la couche transport
Reference number
ISO 29281-1:2013(E)
©
ISO 2013

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ISO 29281-1:2013(E)

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ISO 29281-1:2013(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 2
5 Architectures . 2
5.1 Modes of operation . 2
5.2 FNTP reference architecture . 3
5.3 Communication principles. 3
5.4 Implementation architectures . 4
6 Protocol elements . 6
6.1 Service access points . 6
6.2 FNTP NPDU . 7
6.3 Protocol management elements .11
7 Protocol procedures .13
7.1 Service access points .13
7.2 Port management .13
7.3 Maintenance of entries in forwarding tables .13
7.4 Initial settings of forwarding tables in ITS-S hosts .14
7.5 Initial settings of forwarding tables in ITS-S routers .15
7.6 Transmitting packets .15
7.7 Receiving packets.18
7.8 Management of forwarding tables .20
7.9 CIP management.21
8 NF-SAP services .22
8.1 Overview .22
8.2 NF-FNTP-PORT .22
8.3 NF-FNTP-COMM .23
9 Conformance .25
10 Test methods .26
Annex A (normative) ASN.1 modules .27
Bibliography .31
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ISO 29281-1:2013(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. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
The committee responsible for this document is ISO/TC 204, Intelligent transport systems.
This first edition of ISO 29281-1, together with ISO 29281-2, cancels and replaces ISO 29281:2011.
ISO 29281 consists of the following parts, under the general title Intelligent transport systems —
Communication access for land mobiles (CALM) — Non-IP networking:
— Part 1: Fast networking and transport layer protocol (FNTP)
— Part 2: Legacy system support
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ISO 29281-1:2013(E)

Introduction
This part of ISO 29281 is part of a series of International Standards for communications access for land
mobiles (CALM). An introduction to the whole set of International Standards is provided in ISO 21217.
This part of ISO 29281 is part 1 of a multipart standard which determines the intelligent transport
systems (ITS) non-IP communications.
An essential protocol for non-IP communications is the “Fast networking & transport layer protocol”
(FNTP). FNTP distinguishes:
— a basic port mapper protocol, primarily used for single-hop communications between ITS stations;
— protocol extensions for
— N-hop groupcast;
— LPP;
— secured communication;
— ITS station-internal forwarding of packets between ITS-S host ITS-SCUs and ITS-S router ITS-SCUs.
FNTP is validated in the CVIS project.
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INTERNATIONAL STANDARD ISO 29281-1:2013(E)
Intelligent transport systems — Communication access for
land mobiles (CALM) — Non-IP networking —
Part 1:
Fast networking & transport layer protocol (FNTP)
1 Scope
This part of ISO 29281 specifies a protocol of the ITS-S networking and transport layer in support of
efficient ad hoc single-hop communications with optional N-hop broadcast.
This protocol supports ITS station-internal forwarding of packets, i.e. between ITS-S routers and ITS-S
hosts and vice versa. The protocol is named “Fast Networking & Transport Protocol” (FNTP).
2 Normative references
The following referenced documents are indispensable for the application 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: Specification of Packed Encoding Rules
(PER) — Part 2
ISO 21217, Intelligent transport systems — Communications access for land mobiles (CALM) — Architecture
ISO 21218, Intelligent transport systems — Communications access for land mobiles (CALM) — Access
technology support
ISO 24102-1, Intelligent transport systems — Communications access for land mobiles (CALM) — ITS station
management — Part 1: Local management
ISO 24102-3, Intelligent transport systems — Communications access for land mobiles (CALM) — ITS station
management — Part 3: Service access points
ISO 24102-4, Intelligent transport systems — Communications access for land mobiles (CALM) — ITS station
management — Part 4: Station-internal management communications
ISO 24102-5, Intelligent transport systems — Communications access for land mobiles (CALM) — ITS station
management — Part 5: Fast service advertisement protocol (FSAP)
ETSI TS 102 985-1, Intelligent Transport Systems (ITS); Communications Access for Land Mobiles (CALM);
Test specifications for non-IP networking (ISO 29281); Part 1: Protocol implementation conformance
“statement (PICS) proforma
ETSI TS 102 985-2, Intelligent Transport Systems (ITS); Communications Access for Land Mobiles (CALM);
Test specifications for non-IP networking (ISO 29281); Part 2: Test suite structure & test purposes (TSS&TP)
ETSI TS 102 985-3, Intelligent Transport Systems (ITS); Communications Access for Land Mobiles (CALM);
Test specifications for non-IP networking (ISO 29281); Part 3: Abstract test suite and partial PIXIT (ATS)
specification
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ISO 29281-1:2013(E)

3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21217, ISO 24102-3, ISO 24102-4
and the following apply.
3.1
ITS-S port
source and/or destination “endpoint” for communications identified by an integer number
4 Abbreviated terms
FNTP Fast networking & transport protocol
ITS-SP ITS-S port
5 Architectures
5.1 Modes of operation
5.1.1 General context and purpose of FNTP
The “fast networking & transport layer protocol” (FNTP) specified in this part of ISO 29281 is designed
as a protocol of the ITS-S networking and transport layer of the ITS station (ITS-S) architecture which
recognizes the concepts of the bounded, secured and managed ITS-S; and supports the concept of ITS
station communication units (ITS-SCU) to implement roles of an ITS-S in physical units specified (see
ISO 21217, ISO 24102-1, ISO 24102-3 and ISO 24102-4).
FNTP is primarily designed to enable single-hop communication between peer ITS stations with
minimum protocol overhead, and supports optional features.
NOTE ISO 15628 legacy systems support specified in [2] makes use of FNTP.
FNTP supports any kind of ad hoc access technology, e.g. CALM M5, CALM IR. FNTP may be used to
connect source and destination “endpoints” identified by “ITS-S port” (ITS-SP) numbers in peer ITS
stations, where peer ITS stations are uniquely identified by a Link-ID (usually MAC address contained
in it) of the access layer specified in ISO 21218. Consequently, FNTP is a port mapper protocol, usually
located in the transport layer of the OSI model.
5.1.2 Basic mode of operation
The basic mode of operation is the simplest option of FNTP, which is just providing single-hop
communications between instances of ITS stations without applying any of the options of FNTP.
5.1.3 Extended mode of operation
The extended mode of operation supports options of the FNTP, e.g.:
— ITS station-internal forwarding;
— secure communications;
— N-hop broadcast;
— LPP support;
— CIP management.
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ISO 29281-1:2013(E)

ITS station-internal forwarding is a special option referred to as “station-internal forwarding mode
of operation”.
Other options may be added in a future revision of this part of ISO 29281.
5.2 FNTP reference architecture
Figure 1 illustrates the location of FNTP in the ITS station (ITS-S) specified in ISO 21217, and the
communication relations with other protocol entities.
API
Communications
ITS Management Entity
ITS-S Facilities Layer
NF-SAP
CI Selection
ITS-S Networking & Transport Layer
Manager
Port management
FNTP
IN-SAP
CI Manager
ITS-S Access Layer
ISO 21216 ISO 21215 ISO 21214 LAN CI
Other CIs
supporting supporting supporting ITS station-
MAC MAC MAC internal
groupcast groupcast groupcast network
frames frames frames access
Figure 1 — FNTP reference architecture
The “Port management” is specified as part of FNTP, but may also be used for other ITS-S networking
and transport layer protocols.
The “CI Selection Manager” is specified in ISO 24102-1. The “CI Manager” is specified in ISO 24102-1
and ISO 21218. These two managers are supporting FNTP, but FNTP does not necessarily depend on
these managers.
5.3 Communication principles
5.3.1 Transmission
Transmission requests may be presented by the ITS-S facilities layer via the NF-SAP. Sources and
destinations of messages in the ITS-S facilities layer are identified by ITS-SP numbers.
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MF-SAP
MI-SAP MN-SAP
SI-SAP SN-SAP SF-SAP
ITS-S Security Entity

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ISO 29281-1:2013(E)

Valid transmission requests to a groupcast MAC address are given by a “well-known” destination port
address in combination with an existing groupcast VCI. The value of the source port address is irrelevant
with respect of validity of a transmission request in case no reply is expected. Replies to groupcast
messages are expected, e.g. in case of the service advertisement message specified in ISO 24102-5.
Valid transmission requests to a unicast MAC address are given by any valid destination port address in
combination with an existing unicast VCI. The value of the source port address is irrelevant with respect
of validity of a transmission request in case no reply is expected.
Transmission requests are presented by the FNTP to the ITS-S access layer using services of the IN-SAP.
NOTE In a CALM compliant ITS station, assignment of VCIs to ITS-S applications is done automatically by the
CI selection management specified in ISO 24102-1.
5.3.2 Reception
Reception notifications may be presented by the ITS-S access layer to the FNTP using services of the IN-
SAP. Sources and destinations of messages are identified by ITS-SP numbers contained in the FNTP NPDU.
Valid notified packets addressed to an ITS-SP are given by a known destination port address. Which CI
was used for reception of the packet, and which is the source port address of the packet, are not relevant
for the validity of the packet, but are relevant for a potential reply.
Notifications of received packets are presented by the FNTP to the ITS-S facilities layer using services
of the NF-SAP.
5.3.3 FNTP ITS-SPs
Allocation and deletion of dynamic and static well-known “ITS-S port” (ITS-SP) numbers is specified in 8.2.
NOTE Static well-known ITS-SP numbers are assigned to ITS applications by a registration authority, see [4].
5.4 Implementation architectures
FNTP may support the implementation architectures introduced in ISO 21217 and illustrated in
Figures 2, 3 and 4 with the peer ITS stations A and B, indicating FNTP in the ITS-S networking and
transport layer.
Combined ITS-S router / host Combined ITS-S router / host
A B
Applications Applications
Facilities layer Facilities layer
Networking & transport Networking & transport
layer (FNTP) layer (FNTP)
Access layer (CIs) Access layer (CIs)
Communication link between ITS-Ss
Figure 2 — Implementation architecture I
In case the FNTP is implemented in an ITS-SCU which does not have both roles of ITS-S host and ITS-S
router, the ITS station-internal network shall be supported. This situation is illustrated in Figures 3 and 4.
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Management
Security
Management
Security

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ISO 29281-1:2013(E)

ITS-S host A
Applications
ITS-S router A
Facilities layer
Networking & transport Networking & transport
layer (FNTP) layer (FNTP)
Access layer (LAN CI) LAN CI Other CIs
ITS station-internal network A
ITS-S host B
Applications
ITS-S router B
Facilities layer
Networking & transport Networking & transport
layer (FNTP) layer (FNTP)
Access layer (LAN CI) LAN CI Other CIs
ITS station-internal network B
Figure 3 — Implementation architecture II
© ISO 2013 – All rights reserved 5
Management Management
Security Security
Management Management
Security Security
Communiaction link between
ITS-Ss

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ISO 29281-1:2013(E)

ITS-S host A
Applications
ITS-S router A
Facilities layer
Networking & transport Networking & transport
layer (FNTP) layer (FNTP)
Access layer (LAN CI) LAN CI Other CIs
ITS station-internal network A
Combined ITS-S router / host B
Applications
Facilities layer
Networking & transport
layer (FNTP)
Access layer
(CIs)
Figure 4 — Implementation architecture III
6 Protocol elements
6.1 Service access points
6.1.1 IN-SAP
The FNTP shall support IN-SAP functionality as specified in ISO 21218.
The FNTP is identified in the IN-SAP with the appropriate SAP address “fast communication without
IPv6 addresses” as specified in ISO 21218. Only the even value of the two possible address values shall
be applied for FNTP, as FNTP does not distinguish commands and responses.
NOTE An EtherType value for the FNTP [3] might be allocated to be used in MAC frames. However, this is
outside the scope of this part of ISO 29281.
6.1.2 NF-SAP
The FNTP shall support NF-SAP functionality with details specified in this part of ISO 29281.
6.1.3 MN-SAP
The FNTP shall support MN-SAP functionality identified in this part of ISO 29281 and specified in ISO 24102-3.
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Management
Management
Security
Management
Security
Communication link between
ITS-Ss
Security

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ISO 29281-1:2013(E)

6.1.4 SN-SAP
The FNTP may support functionality of the SN-SAP specified in ISO 24102-3 in order to enable secure
communications.
6.2 FNTP NPDU
6.2.1 Structure
An FNTP NPDU shall consist of two fields as illustrated in Figure 5, i.e. the FNTP header and the FNTP body.
FNTP NPDU
FNTP header FNTP body
Figure 5 — Structure of an FNTP NPDU
ASN.1 details of the FNTP NPDU shall be as specified in Annex A.
6.2.2 FNTP header
6.2.2.1 Structure
The FNTP header illustrated in Figure 6 shall consists of two address fields for sourcePort and
destinationPort, an FNTP control field, and Options fields as required by the value contained in the
FNTP control field.
FNTP header
sourcePort destinationPort
FNTP Control Options
PortNumber PortNumber
Figure 6 — Structure of an FNTP NPDU header
6.2.2.2 sourcePort and destinationPort
The FNTP header shall contain the numbers of source port and destination port of the given hop,
respectively, as illustrated in Figure 6, i.e. indicating “end-points” as specified in Table 1.
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ISO 29281-1:2013(E)

Table 1 — ITS port numbers
Port Acronym Description Field
number size
0 PORT_SAM Groupcast manager, i.e. the sourcePort and destinationPort of “Service 1 octet
Advertisement Messages” (SAM) and “Service Context Messages” (CTX)
specified in ISO 24102-5(FSAP).
1 - 127 PORT_DYN Sub-division into a number range for static ports (PORT_REG) and for
PORT_REG dynamic ports (PORT_DYN) preferably is done by a port number registra-
tion authority, or by future revisions of this document.
Dynamic numbers are for general usage excluding “Legacy CI Port Man-
ager” and “15628 Kernel Emulator” specified in [2].
128 - PORT_DYN Sub-division into a number range for static ports (PORT_REG) and for 2 octets
32716 PORT_REG dynamic ports (PORT_DYN) preferably is done by a port number registra-
tion authority, or by future revisions of this document.
Dynamic numbers are for general usage including “Legacy CI Port Man-
ager” and “15628 Kernel Emulator” specified in [2].
32717 - PORT_RES Reserved for special purposes.
32763
32764 PORT_IIC Port number for ITS station-internal management communications speci-
fied in ISO 24102-4.
32765 PORT_RTR FNTP management port in an ITS-S router, used in ITS station-internal
forwarding mode of operation.
32766 PORT_HST FNTP management port in an ITS-S host, used in ITS station-internal for-
warding mode of operation.
32767 PORT_UNK Unknown / don’t care.
NOTE Values of port numbers as shown above are examples. Assignment of numbers is expected to be done
by a port number registration authority, see [4].
6.2.2.3 Selection of options
6.2.2.3.1 FNTP control field
Details of the “FNTP Control” and “Options” fields depends on the mode of operation:
— basic mode of operation;
— extended mode of operation.
The “FNTP Control” field value allows distinguishing details of these two modes of operation as specified
in Table 2. The FNTP control field is a one octet bit-field as specified in Table 2.
The basic mode of operation is indicated by the value zero in the “FNTP Control” field. In this case, the
FNTP NPDU is referred to as “FNTP basic NPDU” in this part of ISO 29281.
In the extended mode of operation, at least one “Option” field is present. Bit B7 indicates presence or
absence of the first optional element following the FNTP control field; Bit B6 indicates presence or
absence of the second optional element following the FNTP control field; and so on; Bit B0 indicates
presence or absence of the last optional element following the FNTP control field. Presence of an optional
element shall be indicated by a value ‘1’b in the respective bit field.
Reserved bits shall be set to the value ‘0’.
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ISO 29281-1:2013(E)

Table 2 — “FNTP Control” field (implemented as OPTION selector in ASN.1)
B7 B6 B5 B4 B3 B2 B1 B0 Description
‘0’ ‘0’ ‘0’ ‘0’ ‘0’ ‘0’ ‘0’ ‘0’ Used in the NF-FNTP-COMM service to indicate,
that no extension is to be applied.
‘1’ no no no no no no no Option 0: ITS station-internal forwarding. The
value value value value value value value related Options field is present.
no ‘1’ no no no no no no Option 1: Support of secure communications. The
value value value value value value value related Options field is present.
no no ‘1’ no no no no no Option 2: N-hop broadcast. The related Options
value value value value value value value field is present.
no no no ‘1’ no no no no Option 3: So far undefined feature. The related
value value value value value value value Options field is of ASN.1 NULL type. Reserved for
future.
no no no no ‘1’ no no no Option 4: So far undefined feature. The related
value value value value value value value Options field is of ASN.1 NULL type. Reserved for
future.
no no no no no ‘1’ no no Option 5: So far undefined feature. The related
value value value value value value value Options field is of ASN.1 NULL type. Reserved for
future.
no no no no no no ‘1’ no Option 6: LPP support. The related Options field is
value value value value value value value present.
no no no no no no no ‘1’ Option 7: CIP support. The related Options field is
value value value value value value value present.
An FNTP NPDU with “FNTP Control” field containing a value different to ‘00000000’b is referred to as
“FNTP extended NPDU” in this International Standard.
6.2.2.3.2 ITS station-internal forwarding
In order to forward an FNTP NPDU station-internally between an ITS-S host and an ITS-S router or vice
versa, the FNTP header shall contain values as specified in Table 3.
Table 3 — FNTP header values for station-internal forwarding
Forwarding direction sourcePort field destinationPort field
From FNTP management in ITS-S router to FNTP PORT_RTR PORT_HST
management in ITS-S host
From FNTP management in ITS-S host to FNTP PORT_HST PORT_RTR
management in ITS-S router
The FNTP Options field for station-internal forwarding shall be as illustrated in Figure 7.
"Options" for station-internal forwarding
ITS-SCU-ID Link-ID VCI in sourcePort destinationPort
Counter
ITS-S host ITS-S router PortNumber PortNumber
Figure 7 — FNTP header Options field for station-internal forwarding
ASN.1 details of the FNTP header Options field for station-internal forwarding illustrated in Figure 7
shall be as specified in Annex A.
The format of ITS-SCU-ID shall be as specified in ISO 24102-1. The format of Link-ID shall be as specified
in ISO 21218.
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ISO 29281-1:2013(E)

The field “Counter” shall contain a cyclic packet counter being unique in the source ITS-SCU. The size of
this field shall be one octet as specified in Annex A.
The fields sourcePort and destinationPort contain the port numbers used in the link between the peer
ITS stations.
An FNTP NPDU for ITS station-internal forwarding is referred to as “FNTP forwarding NPDU” in this
part of ISO 29281.
6.2.2.3.3 Secure communications
The FNTP Options field in support of secure communications shall be as illustrated in Figure 8.
"Options" in support of secure communications
Length Security elements
Figure 8 — FNTP header Options field in support of secure communications
Details of secure communications are not specified in this version of this part of ISO 29281.
ASN.1 details of the FNTP header Options field in support of secure communications illustrated in
Figure 8 shall be as specified in Annex A.
6.2.2.3.4 N-hop broadcast
The FNTP Options field for N-hop broadcast shall be as illustrated in Figure 9.
"Options" for N-hop broadcast
FNTP hop count
Figure 9 — FNTP header Options field for N-hop broadcast
ASN.1 details of the FNTP header Options field for N-hop broadcast illustrated in Figu
...