ISO 19080:2016

INTERNATIONAL ISO
STANDARD 19080
First edition
2016-10-01
Intelligent transport systems —
Communications access for land
mobiles (CALM) — CoAP facility
Systèmes intelligents de transport — Accès aux communications des
services mobiles terrestres (CALM) — Équipements CoAP
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
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ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
5 Requirements . 3
5.1 Categories . 3
5.2 ITS-S nodes implementing CoAP . 4
5.2.1 General. 4
5.2.2 Requirements on all ITS-S CoAP nodes . 6
5.3 CoAP functional modules . 7
5.3.1 General. 7
5.3.2 CoAP management module. 8
5.3.3 CoAP security module .11
5.4 Optional module .12
5.4.1 General.12
5.4.2 CoAP/HTTP interoperability .13
5.4.3 Resource directory .15
5.4.4 Blockwise transfers .16
5.5 Modules implemented in ITS-S CoAP nodes . .17
5.5.1 General.17
5.5.2 ITS-S CoAP full function device modules .17
5.5.3 ITS-S CoAP reduced function device modules .17
Bibliography .18
Foreword
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The committee responsible for this document is ISO/TC 204, Intelligent transport systems.
iv © ISO 2016 – All rights reserved

Introduction
The set of International Standards that collectively refer to communications access for land mobile
(CALM) focus on the specification of open interfaces regarding the functionality required by all relevant
layers and entities of a Standard ITS station reference architecture.
These International Standards are designed to allow interoperable instantiations of ITS stations, which
are based on the concept of abstracting applications and services from the underlying communication
layers. This abstraction makes the ITS station architecture described herein ideally suited to the
development and deployment of Cooperative ITS applications and services.
The set of CALM International Standards include specifications for security in ITS communications,
ITS-S management, distributed ITS-S implementations, legacy communication media interfaces, legacy
application interfaces and new communication interfaces specifically designed for ITS applications,
such as those designed for safety of both life and property.
The fundamental advantage of the CALM concept with respect to traditional systems is the ability to
support vertical handovers between the various media that can be included in a CALM system. Handover
mechanisms are defined within the CALM architecture International Standard (ISO 21217), the CALM
medium service access points International Standard (ISO 21218) and the CALM communication and
station management International Standard (ISO 24102).
At network layer, CALM IPv6 networking ISO 21210 and CALM 6LoWPAN networking ISO 19079
determine the network protocols to support reachability at a global IPv6 address for Wireless Sensor
Networks (WSNs) based on the IEEE 802.15.4 access medium.
CALM compliant networks (both in-vehicle and off-vehicle) are expected to interact with each other
to seamlessly exchange information. This should be true also for information retrieved from WSN
to be dispatched to any ITS-Station. As WSNs are largely based on low-cost Component of The Shelf
(COTS), IETF has started the standardization of a set of protocols at network and facility layer suited
for constrained devices (in terms of capability of processing, storage or communication) based on low-
rate wireless personal area networks (LR-WPANs) technologies. An important candidate at application
layer in this sense is the IETF Constrained Application Protocol (CoAP) (IETF RFC 7252), an optimized
Representational State Transfer (REST) protocol built on top of the UDP transport protocol, and
implementing a subset of HTTP specifications. This document specifies some facility protocols by
leveraging the reachability of the WSN nodes guaranteed by the adoption of 6LoWPAN at the Network
Layer, and describes how to use CoAP protocol specified by IETF in the context of C-ITS.
For a general introduction to CALM architecture, IPv6 networking and 6LoWPAN networking, the
reader is referred to ISO 21217, ISO 21210 and ISO 19079, respectively.
INTERNATIONAL STANDARD ISO 19080:2016(E)
Intelligent transport systems — Communications access
for land mobiles (CALM) — CoAP facility
1 Scope
This document describes the CoAP facilities between two or more ITS stations communicating over the
global internet communication network.
It is assumed that the reader is familiar with IETF specifications found in request for comments (RFCs)
of individual CoAP and 6LoWPAN protocol blocks used within this document. This document does
not define a new protocol, a new exchange of messages at the CoAP layer, or new data structures. It
defines how protocols standardized by IETF are combined so that ITS stations can communicate with
one another using CoAP. Procedures defined to share information between the CoAP layer and other
components of the ITS station architecture are defined in ISO 24102 series (Management). In addition
to the requirements specified within this document, a number of notes and examples are provided to
illustrate CoAP main facilities.
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 21217:2014, Intelligent transport systems — Communications access for land mobiles (CALM) —
Architecture
1)
ISO 24102-6 , Intelligent transport systems — Communications access for land mobiles (CALM) — ITS
station management — Part 6: Path and flow management
IETF RFC 6690, The Constrained RESTful Environments (CoRE) Link Format
IETF RFC 7252:2014, The Constrained Application Protocol (CoAP)
IETF RFC 7641, Observing Resources in the Constrained Application Protocol (CoAP)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19079, ISO 21210, ISO 21217,
ISO 21218, ISO 24102-3 and the following 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
NOTE Most of the definitions are taken from IETF RFC 7252, IETF RFC 7228 and IETF RFC 6690.
3.1
ITS-S CoAP node
device/node that implements CoAP protocol
[SOURCE: IETF RFC 7252]
1) To be published.
3.2
ITS-S CoAP Endpoint
entity participating in the CoAP protocol
Note 1 to entry: Colloquially, an endpoint lives on a “node”, although “host” would be more consistent with
Internet standards usage, and is further identified by transport-layer multiplexing information that can include a
UDP port number and a security association.
[SOURCE: IETF RFC 7252]
3.3
ITS-S CoAP Client
originating endpoint of a request; the destination endpoint of a response
[SOURCE: IETF RFC 7252]
3.4
ITS-S Server
destination endpoint of a request; the originating endpoint of a response
[SOURCE: IETF RFC 7252]
3.5
confirmable message
message requiring an acknowledgement
Note 1 to entry: These messages are called “confirmable”. When no packets are lost, each confirmable message
prompts exactly one return message of type acknowledgement or type reset.
[SOURCE: IETF RFC 7252]
3.6
non-confirmable message
message not requiring an acknowledgement
Note 1 to entry: This is particularly true for messages that are repeated regularly for application requirements,
such as repeated readings from a sensor.
[SOURCE: IETF RFC 7252]
3.7
acknowledgement message
message acknowledging that a specific confirmable message arrived
Note 1 to entry: By itself, an acknowledgement m
...