ETSI TS 102 636-3 V1.1.1 (2010-03)

ETSI TS 102 636-3 V1.1.1 (2010-03)
Technical Specification


Intelligent Transport Systems (ITS);
Vehicular Communications;
GeoNetworking;
Part 3: Network architecture

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2 ETSI TS 102 636-3 V1.1.1 (2010-03)



Reference
DTS/ITS-0030004
Keywords
addressing, ITS, network, point-to-multipoint,
point-to-point, protocol
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3 ETSI TS 102 636-3 V1.1.1 (2010-03)
Contents
Intellectual Property Rights . 4
Foreword . 4
Introduction . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 6
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 7
4 Network architecture for ITS stations . 8
5 Deployment scenarios of the generic network architecture. 10
6 Components of the network architecture . 11
6.1 General . 11
6.2 Sub-components of vehicle ITS stations and roadside ITS stations . 12
6.3 Network connectivity among ITS stations . 13
6.4 Network reference points . 14
7 ITS station protocol architecture . 15
7.1 Protocol stack overview . 15
7.2 Protocols of the ITS network & transport layer . 16
7.3 Assembly of network and transport protocols in the ITS station protocol stack . 17
7.3.1 Overview . 17
7.3.2 GeoNetworking protocol stack . 17
7.3.3 IPv6 stack . 17
7.3.4 Combination of the GeoNetworking protocol and IPv6 . 18
7.3.5 Protocol stacks for other network protocols . 18
8 Interfaces and service access points . 18
9 Frameworks for network and transport protocols . 20
9.1 GeoNetworking . 21
9.1.1 Ad hoc networking. 21
9.1.2 Addressing . 21
9.1.3 Resource management and data congestion control . 21
9.1.4 Integration of GeoNetworking and IPv6 . 21
9.1.5 Backward compatibility to IPv4 . 21
9.1.6 Usage of multiple ITS access technologies . 22
9.1.7 Security and privacy protection . 22
9.2 Other protocol stacks . 22
History . 23

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4 ETSI TS 102 636-3 V1.1.1 (2010-03)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Intelligent Transport System (ITS).
The present document is part 3 of a multi-part deliverable. Full details of the entire series can be found in part 1 [i.13].
Introduction
The present document specifies the network architecture for communication-based Intelligent Transport Systems (ITS)
using different ITS access technologies, such as ITS-G5. The network architecture provides - in combination with the
description of scenarios - a basis for the technical specification of the network and transport protocols, in particular for
GeoNetworking and its related protocols.
The present document first introduces a generic, high-level system view of the network architecture and defines four
basic deployment scenarios. Based on the system view, it identifies and describes the main network components and
specifies network reference points among them. Central component of the architecture is the ITS station. For this
component, an overview of its protocol architecture is given and different options of using the GeoNetworking protocol
in combination with transport protocols and protocols of the IP suite are described. Finally, the present document
defines frameworks for different aspects of networking and data transport, such as ad hoc communication, addressing,
resource management and data congestion control, integration with protocols of the IP suite and others.
The network architecture is based on the ITS architecture specified in [1] and represents the networking viewpoint of
the overall architecture.
Sources of input for the present document are [i.1], [i.2] and [i.3].
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5 ETSI TS 102 636-3 V1.1.1 (2010-03)
1 Scope
The present document specifies the network architecture for communication-based Intelligent Transport Systems (ITS).
The network architecture is focused on, but not limited to, vehicular communication. The architecture enables a wide
range of ITS applications for road safety, traffic efficiency as well as for infotainment and business.
The present document defines the framework for network and data transport protocols that provide data exchange
among ITS stations. A particular aspect is the GeoNetworking protocol that provides ad hoc and multi-hop
communication over short-range wireless technologies utilizing geographical positions.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
- if it is accepted that it will be possible to use all future changes of the referenced document for the
purposes of the referring document;
- for informative references.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
[1] ETSI EN 302 665: "Intelligent Transport Systems (ITS); Communications Architecture".
[2] ISO/IEC 7498-1: "Information technology - Open Systems Interconnection - Basic Reference
Model: The Basic Model".
[3] ISO/IEC 8802-2: " Information technology - Telecommunications and information exchange
between systems - Local and metropolitan area networks - Specific requirements; Part 2: Logical
Link Control".
[4] IETF RFC 791: "Internet Protocol".
[5] IETF RFC 2460: "Internet Protocol, Version 6 (IPv6) Specification".
[6] IETF RFC 3775: "Mobility Support in IPv6".
[7] IETF RFC 768: "User Datagram Protocol".
[8] IETF RFC 793: "Transmission Control Protocol".
[9] IETF RFC 3963: "Network Mobility (NEMO) Basic Support Protocol".
[10] IETF RFC 5213: "Proxy Mobile IPv6".
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6 ETSI TS 102 636-3 V1.1.1 (2010-03)
2.2 Informative references
The following referenced documents are not essential to the use of the present document but they assist the user with
regard to a particular subject area. For non-specific references, the latest version of the referenced document (including
any amendments) applies.
[i.1] COMeSafety Deliverable 3.1 - Version 2.0 - March 2009: "European ITS Communication
Architecture - Overall Framework - Proof of Concept Implementation.
[i.2] PRE-DRIVE C2X Deliverable 1.4 - Version 1.2 - August 2009: "Refined Architecture". .
[i.3] GeoNet Deliverable 1.1 - Version 1.0 - March 2009: "Preliminary Architecture Design".
[i.4] ITU-R Recommendation M.687-2: "International Mobile Telecommunications 2000 (IMT-2000)".
[i.5] IETF RFC 3753: "Mobility Related Terminology".
[i.6] 3GPP: "UMTS Standard, Release 08 Specification".
NOTE: Available at: http://www.3gpp.org.
[i.7] IETF RFC 4213: "Basic Transition Mechanisms for IPv6 Hosts and Routers".
[i.8] IETF RFC 2185: "Routing Aspects of IPv6 Transition".
[i.9] ETSI TS 102 637-1: "Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set
of Applications; Part 1: Functional Requirements".
[i.10] ETSI TS 102 637-2: "Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set
of Applications; Part 2: Specification of Co-operative Awareness Basic Service".
[i.11] ETSI TS 102 637-3: "Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set
of Application; Part 3: Specification of Decentralized Environmental Notification Basic Service".
[i.12] ETSI ES 202 663: "Intelligent Transport Systems (ITS); European profile standard for the physical
and medium access control layer of Intelligent Transport Systems operating in the 5 GHz
frequency band".
[i.13] ETSI TS 102 636-1: "Intelligent Transport Systems (ITS); Vehicular Communications;
GeoNetworking; Part 1: Requirements".
[i.14] ETSI TS 102 731: "Intelligent Transportation Systems (ITS); Security; Security Services and
Architecture".
[i.15] ETSI TS 102 723 (all parts): "Intelligent Transport Systems; OSI cross-layer topics".
[i.16] ETSI TS 102 636-5: "Intelligent Transport Systems (ITS); Vehicular Communications;
GeoNetworking; Part 5: Transport Protocols".
[i.17] ETSI TS 102 636-4-1: "Intelligent Transportation System (ITS); Vehicular communications;
GeoNetworking; Part 4: Geographical addressing and forwarding for point-to-point and point-to-
multipoint communications; Subpart 1: Media independent functionalities".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in [1] and [2] and the following apply:
access router: IPv6 router that provides access to other networks, such as to the ITS access network
NOTE: The definition is taken from [i.5] and adapted to the ITS network architecture.
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access network gateway: router at the edge of a network that connects an ITS station-internal network to the ITS
access network, the public access network, and the private access network
ad hoc network: wireless networks based on self-organization without the need for a coordinating infrastructure
application unit: physical unit in an ITS station that executes applications and uses the communication services of a
communication & control unit (CCU)
communication & control unit: physical communication unit located in an ITS station that implements
communication protocols and provides communication services
GeoNetworking: network service that utilizes geographical positions and provides ad hoc communication without the
need for a coordinating communication infrastructure
GeoNetworking protocol: network protocol that provides the GeoNetworking service
legacy roadside infrastructure: road infrastructure, e.g. road sensors, loops, networks, switches, router, processing
entities, etc.
legacy services: legacy Internet services, such as WWW, email, Internet access, file transfer, etc.
ITS access network: communication network that interconnects roadside ITS stations among each other in an ITS
specific way and optionally interconnects them to the core network (e.g., the Internet)
ITS ad hoc network: network of the ITS architecture that enables self-organized communication among ITS stations
without the need for a coordinating communication infrastructure
ITS operational support service: service for operation of the ITS, such as the provision of security credentials to
users/ vehicle drivers
ITS station internal network: network that interconnects the different components of an ITS station
mobile network: entire network, moving as a unit, which dynamically changes its point of attachment to the Internet
and thus its reachability in the topology
mobile router: IPv6 router that acts as getway between a IPv6 mobile network and another IP-based network, and
capable of changing its point of attachment to the network, moving from one link to another link
private access network: network that provides data services to a closed user group for a secured access to another
system
proprietary local network: communication network attached to an ITS station, for example a controller area
network (CAN) in a vehicle or a network of roadside legacy infrastructure
public access network: network that provides access to general purpose networks that are publicly accessible
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in [1] and [2] and the following apply:
AU Application Unit
CAN Controller Area Network
CCU Communication and Control Unit
DCC Decentralized Congestion Control
GPRS General Packet Radio Service
IMT International Mobile Telecommunications
IP Internet Protocol
NEMO Network Mobility
PDCP Packet Data Convergence Protocol
TCP Transmission Control Protocol
TIC Transmit Interval Control
TPC Transmit Power Control
UDP User Datagram Protocol
UE User Equipment
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UMTS Universal Mobile Telecommunication System
WIMAX Worldwide Interoperability for Microwave Access
WWW World Wide Web
4 Network architecture for ITS stations
The network architecture comprises external and internal networks. External networks interconnect ITS stations among
each other or connect ITS stations to other instances. The following external networks are identified:
• ITS ad hoc network.
• Access network (ITS access network, public access network, private access network).
• Core network (e.g. the Internet).
Additionally, an ITS station can have an internal network that interconnects the components of the ITS station.
The different networks shall provide support for various use cases of road safety, traffic efficiency, infotainment and
business applications. However, it is presumed that the communication within a single network does not meet all the
requirements of all applications and use cases. Instead combinations of networks are envisioned, in which multiple ITS
access and networking technologies are applied.

Figure 1: External networks involved in the ITS architecture and their interconnections
Figure 1 represents the highest level of abstraction of the ITS network architecture, where the external networks,
represented by clouds are connected. The networks can be categorized into an ITS domain and a generic domain as
specified in [1]. The external networks can be described as follows:
The ITS ad hoc network enables ad hoc communication among vehicle, roadside and personal ITS stations. The
communication is based on wireless technologies, that typically provide a limited communication range (referred to as
'short-range wireless technology') and allow for mobility of the ITS stations forming arbitrary network topologies
without the need for a coordinating communication infrastructure. An example of an ITS ad hoc network is a network of
vehicle, roadside and personal ITS stations interconnected by ITS-G5 [10] wireless technology.
Generally, an access network enables ITS stations to access networks.
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An ITS access network is a dedicated network that provides access to specific ITS services and applications and can be
operated by a road operator or other operators. The ITS access network also interconnects roadside ITS stations and
provides communication in between these as well as among vehicle ITS stations via the roadside ITS stations that are
interconnected in the ITS access network. This local network can then enable the vehicle ITS stations to communicate
via a roadside infrastructure communication network instead directly in ad hoc mode. As an example, an ITS access
network can connect roadside ITS stations along a highway with a central ITS station (e.g. a road traffic management
centre). In the case that short-range wireless technology is used for communication via roadside ITS stations, the
connectivity to the ITS access network is typically provided intermittently.
A public access network provides access to general purpose networks that are publicly accessible. An example is an
IMT-2000 [i.4] network that connects vehicle ITS stations to the Internet and provides mobile Internet access.
A private access network, in contrast to a public access network, provides data services to a closed user group for a
secured access to another network. For example, a private access network can connect vehicle ITS stations to a
company's intranet.
The access networks and the core network provide access to various services:
• legacy services , such as WWW, email and many others;
• ITS services provided by road traffic management centres and backend services;
• ITS operational support services required to operate the ITS, such as security services.
Core component of the architecture is the ITS station, which has two main roles: In its first role, the ITS station is a
network node and acts as a communication source or sink. Likewise an ITS station can be a forwarder of data, e.g. in
the ITS ad hoc network. In its second role, the ITS station is placed at the network edge and connect the different
networks via an ITS station internal network (see Figure 1).
ITS stations shall be able to communicate via at least one of the following means (see Figure 2):
a) via an ITS ad hoc network;
b) via an ITS access network;
c) via a public access network;
d) via a private access network;
e) via one of the access networks into the core network (e.g. the Internet).
In addition to the networks listed above, an ITS station can also be attached to proprietary local networks of e.g. vehicle
ITS sub-systems and roadside ITS sub-system as presented in [1]. Typical examples are:
• Controller Area Network (CAN) in a vehicle ITS sub-system.
• Legacy roadside infrastructure in a roadside ITS sub-system.
However, these proprietary networks are outside the scope of the present document.
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Figure 2: High-level network architecture
5 Deployment scenarios of the generic network
architecture
The ITS network architecture can be deployed in different scenarios to adapt to specific economical and regulatory
conditions and to facilitate a gradual introduction of ITS. Basically, a deployment scenario is a subset of the overall
architecture (see Figure 2) created by a combination of the different network types.
Four basic deployment scenarios can be defined. The basic deployment scenarios can further be extended to hybrid
scenarios that combine two or more deployment scenarios. These combinations also include scenarios in which a
network is connected to more than a single network simultaneously.
Scenario A establishes an ITS ad hoc network, which can be connected via an ITS access network to the core network
(e.g. the Internet) (see Figure 3). Deployment scenario B represents an ITS access network, which can be connected to
the core network (e.g. the Internet) (see Figure 4). Deployment scenario C is based on a public access network, which
can also provide connectivity to the core network (e.g. the Internet) (see Figure 5). Deployment scenario D uses a
private access network to connect to other networks or the core network (e.g. the Internet) (see Figure 6).

Figure 3: Deployment scenario A: Ad hoc-centric
In Figure 4, the ITS access network connects roadside ITS stations to each other and provides connectivity to a core
network (e.g. the Internet). Optionally, the ITS access network can also be replaced by a public or private access
network.
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Figure 4: Deployment scenario B: ITS access network-centric

Figure 5: Deployment scenario C: Public access network-centric

Figure 6: Deployment scenario D: Private access network-centric
6 Components of the network architecture
6.1 General
Main component of the network architecture is the ITS station as specified in [1] with the following sub-systems:
• vehicle ITS station;
• personal ITS station;
• roadside ITS station;
• central ITS station.
In addition to these instantations, the ITS-S Border Router [1] interconnects networks in the ITS domain with networks
in the generic domain. Additionally to the ITS station component, the present document introduces specific network
components related to IPv6 communication [i.5], i.e.:
• ad hoc router;
• mobile router;
• access router; and
• access network gateway;
that will be defined below.
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6.2 Sub-components of vehicle ITS stations and roadside ITS
stations
Vehicle ITS stations and roadside ITS stations consist of two types of sub-components, the Communication & Control
Unit (CCU) and the Application Unit (AU) (Figure 7). In general, a CCU executes a communication protocol stack. An
AU runs a single or a set of applications and utilizes the CCU's communication capabilities.
In a possible implementation, the CCU executes the ITS access technology, ITS network & transport, and the ITS
facilities layers, whereas the ITS application layer resides in the AU. The distinction between AU and OBU is logical;
all layers can also be implemented in a single physical unit.
NOTE: The components of a personal ITS station and central ITS station will be refined at a later stage of the
network architecture definition.
The CCU shall be equipped with at least a single ITS external communication interface to provide connectivity to the
ITS ad hoc network or the different access networks (ITS access network, public access network, private access
network). The CCU and the AU can be equipped with one or multiple ITS internal communication interfaces.
Moreover, an AU can have an external communication interface ('Gateway Interface' in Figure 7) for access to the
proprietary local network.
The ITS internal communication interface shall connect AUs with CCUs, AUs with other AUs, and CCUs with other
CCUs via the ITS station-internal network. AUs and CCUs can form a mobile network [i.5], where the AUs obtain
connectivity to the networks via the external communication interface of the CCU. AU and CCU can reside in a single
physical unit.

Figure 7: Sub-components of a vehicle ITS station and a roadside ITS station
The CCU can be further sub-divided into logical network components of different types operating at the network layer:
• ad hoc router;
• mobile router;
• access router; and
• access network gateway;
that are responsible for routing and forwarding of packets in the corresponding networks.
An ad hoc router shall be associated with the ITS ad hoc network and executes an ad hoc networking protocol, such as
the GeoNetworking protocol.
A mobile router is a network component of the vehicle ITS station and shall provide IP connectivity of the ITS station
internal network to an access
...