Public transport - Road vehicle scheduling and control systems - Part 7: System and network architecture

This document specifies the general rules for an on-board data communication system between the different systems that may be used within public transport vehicles, based on the Internet Protocol (IPv4, [3] and IPv6, [4]). This includes operational support systems, passenger information systems, fare collection systems, etc.
This document describes:
-   the requirements for an on board IP network;
-   the overview architecture and components for an IP based on-board network;
-   the modular structure of the network architecture;
-   the Service Oriented Architecture (SOA) approach, and approach to defining services.
Systems directly related to the safe operation of the vehicle (including propulsion management, brake systems, door opening systems) are excluded from the scope of this document and are dealt with in other standardization bodies. However, the architecture described in this document may be used for support services such as safety information messages. Interfaces to safety-critical systems should be provided through dedicated gateways with appropriate security provisions; for the purposes of this document, these are regarded as simply external information sources.
This document is designed primarily for vehicles with a fixed primary structure, where networks can be installed on a permanent basis and the system configuration task consists largely of the integration, adjustment or removal of the functional end systems that produce and/or consume data. Public transport vehicles consisting of units linked temporarily for operational purposes (specifically, trains in which individual engines, cars or consists are routinely connected and disconnected) require additional mechanisms to enable the communications network itself to reconfigure. Such mechanisms are provided through other standards, notably the IEC 61375 series [5].

Öffentlicher Verkehr - Planungs- und Steuerungssysteme für Straßenfahrzeuge - Teil 7: System- und Netzwerkarchitektur

Transport public - Systèmes de planification et de contrôle des véhicules routiers - Partie 7 : Architecture Système et Réseau

Javni prevoz - Sistemi za časovno razporejanje in nadzor cestnih vozil - 7. del: Sistem in arhitektura omrežja

General Information

Status
Published
Publication Date
11-Feb-2020
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
12-Feb-2020
Completion Date
12-Feb-2020

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SLOVENSKI STANDARD
SIST-TS CEN/TS 13149-7:2020
01-april-2020
Nadomešča:
SIST-TS CEN/TS 13149-7:2016
Javni prevoz - Sistemi za časovno razporejanje in nadzor cestnih vozil - 7. del:
Sistem in arhitektura omrežja

Public transport - Road vehicle scheduling and control systems - Part 7: System and

network architecture

Öffentlicher Verkehr - Planungs- und Steuerungssysteme für Straßenfahrzeuge - Teil 7:

System- und Netzwerkarchitektur

Transport public - Systèmes de planification et de contrôle des véhicules routiers - Partie

7 : Architecture Système et Réseau
Ta slovenski standard je istoveten z: CEN/TS 13149-7:2020
ICS:
03.220.20 Cestni transport Road transport
35.240.60 Uporabniške rešitve IT v IT applications in transport
prometu
43.040.15 Avtomobilska informatika. Car informatics. On board
Vgrajeni računalniški sistemi computer systems
SIST-TS CEN/TS 13149-7:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN/TS 13149-7:2020
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SIST-TS CEN/TS 13149-7:2020
CEN/TS 13149-7
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
February 2020
TECHNISCHE SPEZIFIKATION
ICS 35.240.60; 43.040.15 Supersedes CEN/TS 13149-7:2015
English Version
Public transport - Road vehicle scheduling and control
systems - Part 7: System and network architecture

Transport public - Systèmes de planification et de Öffentlicher Verkehr - Planungs- und

contrôle des véhicules routiers - Partie 7 : Architecture Steuerungssysteme für Straßenfahrzeuge - Teil 7:

Système et Réseau System- und Netzwerkarchitektur

This Technical Specification (CEN/TS) was approved by CEN on 8 December 2019 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to

submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS

available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in

parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 13149-7:2020 E

worldwide for CEN national Members.
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Contents Page

European foreword ...................................................................................................................................................... 4

Introduction .................................................................................................................................................................... 5

1 Scope .................................................................................................................................................................... 7

2 Normative references .................................................................................................................................... 7

3 Terms and definitions ................................................................................................................................... 7

4 Symbols and abbreviations ......................................................................................................................... 9

5 Design principles ............................................................................................................................................ 9

5.1 Introduction ...................................................................................................................................................... 9

5.2 Design goals .................................................................................................................................................... 10

5.2.1 Enabling communications ......................................................................................................................... 10

5.2.2 Enabling interoperability .......................................................................................................................... 10

5.2.3 Ease of configuration ................................................................................................................................... 10

5.2.4 Quality of monitoring .................................................................................................................................. 10

5.2.5 Maintainability .............................................................................................................................................. 10

5.2.6 Migration .......................................................................................................................................................... 10

5.2.7 Supporting fleet changes ............................................................................................................................ 10

6 Network architecture .................................................................................................................................. 11

6.1 Introduction .................................................................................................................................................... 11

6.2 Network overview ........................................................................................................................................ 11

6.3 Gateways to other networks ..................................................................................................................... 11

6.4 IP addressing .................................................................................................................................................. 12

6.4.1 General addressing considerations........................................................................................................ 12

6.4.2 Address space ................................................................................................................................................. 12

6.4.3 Manual assignment ...................................................................................................................................... 13

6.4.4 Automatic assignment ................................................................................................................................. 13

6.5 Name registration and resolution of modules ................................................................................... 14

6.5.1 Domain name options ................................................................................................................................. 14

6.5.2 Unicast Domain Name System (DNS) ..................................................................................................... 15

6.5.3 Multicast Domain Name System (mDNS).............................................................................................. 15

6.6 Communication Protocols ......................................................................................................................... 16

6.6.1 HyperText Transfer Protocol (HTTP) ................................................................................................... 16

6.6.2 File Transfer Protocol (FTP) ..................................................................................................................... 16

6.6.3 Secure Shell (SSH) ......................................................................................................................................... 16

6.6.4 Multicast User Datagram Protocol (Multicast-UDP) ........................................................................ 16

6.6.5 Session control ............................................................................................................................................... 17

6.6.6 Data Multicast ................................................................................................................................................ 17

6.6.7 Real-time Transport Protocol (RTP) ..................................................................................................... 18

6.6.8 Network Time Protocol (NTP) / Simple Network Time Protocol (SNTP) ................................. 18

6.6.9 Message Queuing Telemetry Transport (MQTT) .............................................................................. 18

6.7 Network security ........................................................................................................................................... 18

6.8 Considerations on coupled vehicles ....................................................................................................... 18

7 Service architecture ..................................................................................................................................... 19

7.1 Service oriented architecture (SOA) ...................................................................................................... 19

7.2 Service Information ..................................................................................................................................... 19

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7.2.1 Service framework options ....................................................................................................................... 19

7.2.2 Manual configuration .................................................................................................................................. 19

7.2.3 Configuration using DNS-SD ..................................................................................................................... 20

7.3 Communication Types ................................................................................................................................ 21

7.3.1 Event Triggered Data .................................................................................................................................. 21

7.3.2 Streaming of Data ......................................................................................................................................... 21

7.3.3 High Frequency Data ................................................................................................................................... 21

7.4 Data Structure ................................................................................................................................................ 21

7.4.1 Data structure options ................................................................................................................................ 21

7.4.2 XML .................................................................................................................................................................... 22

7.4.3 JSON ................................................................................................................................................................... 22

Annex A (informative) Example usages ............................................................................................................. 23

A.1 Typical vehicle network architecture ................................................................................................... 23

A.2 Function and service groups .................................................................................................................... 24

Bibliography ................................................................................................................................................................. 25

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European foreword

This document (CEN/TS 13149-7:2020) has been prepared by Technical Committee CEN/TC 278

“Intelligent transport systems”, the secretariat of which is held by NEN.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes CEN/TS 13149-7:2015.

In comparison with the previous edition, the following technical modifications have been made:

— reference to normative service specifications dependent on this document;
— addition of reference to MQTT;
— restructuring of SRV record.

This document is Part 7 of a series of European Standards and Technical Specifications that includes:

— CEN/TS 13149-7, Public transport – Road vehicle scheduling and control systems – Part 7: System

and network architecture [this document];

— CEN/TS 13149-8, Public transport – Road vehicle scheduling and control systems – Part 8: Physical

layer for IP communication;

— CEN/TS 13149-9, Public transport – Road vehicle scheduling and control systems – Part 9: Time

service [currently at voting stage];

— CEN/TS 13149-10, Public transport – Road vehicle scheduling and control systems – Part 10:

Location service [currently at voting stage];

— CEN/TS 13149-11, Public transport – Road vehicle scheduling and control systems – Part 11: Vehicle

platform interface service [currently at voting stage].

According to the CEN/CENELEC Internal Regulations, the national standards organisations of the

following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
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Introduction

This Technical Specification is Part 7 of a series of European Standards and Technical Specifications.

The scope of this series is on-board data communication systems on public transport vehicles.

Public Transport (PT) vehicles have an increasing array of information and communications systems,

including ticket machines, Automated Vehicle Location (AVL) systems, destination displays, passenger

announcement systems, vehicle monitoring systems, etc. Other systems are beginning to be included

such as advertising screens, tourist guides, WiFi “hotspots” and infotainment.

In addition, equipped PT vehicle will usually have a communications facility to enable voice and data to

be exchanged with the control centre, other PT vehicles, PT infrastructure and roadside devices for

instance in requesting priority at traffic signals. Many types of communication channel are used

including public and private wireless communication networks.

These systems may be provided by a number of different suppliers and may need to be integrated. For

instance:
— a ticket machine may need location information to update fare stages;

— next-stop and destination information may be drawn from schedule information held in the ticket

machine;
— vehicle location systems may be used to drive signal priority requests.

As data exchange between functional units becomes more widespread, a networked approach begins to

become efficient. With standardized underlying technology, the PT vehicle begins to look like a local

area network: making use of IEEE 802 communications and the Internet Protocol (IP) suite.

Without a clear technology framework, integrating these systems would require complex technical

discussions every time a device is procured. The existing EN 13149 standards recognized this long ago

in respect of the core vehicle systems, but these have not been adapted to IP networking.

Six historical parts of EN 13149, namely Parts 1 to 6, have now been withdrawn in favour of the new IP-

based approach. The core of this new approach was specified in two Technical Specifications (TS):

— CEN/TS 13149-7 specifies the Network and System Architecture for on board equipment. It

describes basic principles of communications including a general description of the network

topology, addresses schematics, basic network services, a system overview and basic module

architecture.

— CEN/TS 13149-8 specifies the Physical Layer for IP-communication networks on board PT vehicles.

This part specifies the cables, connectors and other equipment including pin assignment and

environmental requirements.
Building on this, a series of specific services are being specified:

— CEN/TS 13149-9, specifying the structure to be used by a service providing time data to the on-bus

network;

— CEN/TS 13149-10, specifying the structure to be used by a service providing location data to the

on-bus network, specifically relating to Global Navigational Satellite Systems (GNSS);

— CEN/TS 13149-11, specifying the structure to be used by a service providing data from the vehicle

platform to the on-bus network, using the Fleet Management System (FMS) for source data.

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These documents draw on large scale trials undertaken within European projects such as EBSF (the

“European Bus System of the Future” project) and its successors, together with technical developments

which have since been adopted by programmes such as the German IBIS-IP platform [1] and, more

recently, the European platform ITxPT [2]. This has ensured not only that the CEN specifications are

robustly proved in practice, but also that they have the support of many key system developers and

operators.
With these Technical Specifications, it will be easier to achieve:
— more efficient development of PT components;
— lower cost, lower risks and a smoother on board integration of PT equipment;
— more efficient operation and maintenance of on board PT equipment;
— high quality intermodal passenger services based on intermodal PT information;
— integration of new PT services.

As an IP based solution, this Technical Specification draws on a range of IETF Requests for Comment

(RFCs), not all of which may be formal standards. A list of those cited is presented in the Bibliography.

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1 Scope

This document specifies the general rules for an on-board data communication system between the

different systems that may be used within public transport vehicles, based on the Internet Protocol

(IPv4, [3] and IPv6, [4]). This includes operational support systems, passenger information systems,

fare collection systems, etc.
This document describes:
— the requirements for an on board IP network;
— the overview architecture and components for an IP based on-board network;
— the modular structure of the network architecture;

— the Service Oriented Architecture (SOA) approach, and approach to defining services.

Systems directly related to the safe operation of the vehicle (including propulsion management, brake

systems, door opening systems) are excluded from the scope of this document and are dealt with in

other standardization bodies. However, the architecture described in this document may be used for

support services such as safety information messages. Interfaces to safety-critical systems should be

provided through dedicated gateways with appropriate security provisions; for the purposes of this

document, these are regarded as simply external information sources.

This document is designed primarily for vehicles with a fixed primary structure, where networks can be

installed on a permanent basis and the system configuration task consists largely of the integration,

adjustment or removal of the functional end systems that produce and/or consume data. Public

transport vehicles consisting of units linked temporarily for operational purposes (specifically, trains in

which individual engines, cars or consists are routinely connected and disconnected) require additional

mechanisms to enable the communications network itself to reconfigure. Such mechanisms are

provided through other standards, notably the IEC 61375 series [5].
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
3.1
application

piece of software constructed to capture, process and/or interpret data within the context of a business

process; for example estimating vehicle location within the transport network
3.2
function
logical set of data processing activities that fulfils a business need
EXAMPLE Automated Vehicle Monitoring System (AVMS).
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3.3
module
hardware or virtual component with an IP address on the IP network
EXAMPLE OnBoardUnit (on board computer).
3.4
service
mechanism to deliver data on the IP architecture

EXAMPLE Provision of information about the vehicle location within the transport network.

Note 1 to entry: Thus, a module will host one or more applications which are designed to implement functions; a

service is provided by an application via a module (using an IP port), and communicates across the IP network. In

particular, a module can host several applications, an application can provide several services, and identical

services can be provided multiple times by different applications. Figure 1 depicts this relationship

diagrammatically.
Key
M1 – M4 Modules
SRV1 – SRV5 Services
A1 – A7 Applications
IP Primary network
Figure 1 — Relationship between terms (example)

Note 2 to entry: Applications, and the functions they support, are liable to regularly change and are independent

of the technical features described in this document. Other Parts of the EN 13149 series provide service

definitions for some key individual functions.
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4 Symbols and abbreviations
API Application Programming Interface
AVL Automated Vehicle Location
AVMS Automated Vehicle Monitoring System
CAN Controller Area Network
DHCP Domain Host Control Processor
DNS Domain Name System
DNS-SD DNS based Service Discovery
DPI Dynamic Passenger Information
FTP File Transfer Protocol
FTP File Transfer Protocol
GPS Global Positioning System
HTTP HyperText Transfer Protocol
IP Internet Protocol
IT Information Technologies
LAN Local Area Network
mDNS Multicast DNS
MMI Man Machine Interface
MQTT Message Queuing Telemetry Transport
PT Public Transport
PTA Public Transport Authority
PTO Public Transport Operator
QoS Quality of Service
SOA Service Oriented Architecture
SSH Secure Shell protocol
TELNET TErminaL NETwork
UDP User Datagram Protocol
5 Design principles
5.1 Introduction

This clause describes the design principles adopted in the development of EN 13149 IP-based services.

These consist of:

— the operational characteristics which are routinely required of an integrated on-board systems

network, and the goals for which this Technical Specification has been designed;
— the language used to describe the systems and their connectivity.
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5.2 Design goals
5.2.1 Enabling communications

Different systems on the vehicle may benefit from exchanging data with each other, in an automated

and sometimes real-time manner. This requires a framework which identifies clearly the approach to

configuration and structure of data exchanges through standard mechanisms. IP-based communications

are very mature and capable of delivering this goal.
5.2.2 Enabling interoperability

Similarly, there are advantages in adopting a standard for system architecture and data structures

which is independent of manufacturer. Interconnection between modules of different suppliers will be

facilitated by the use of standardized software and hardware interfaces. The Service Oriented

Architecture approach is now widely used and accepted.
5.2.3 Ease of configuration

The need for manual intervention in the configuration and operation of units can be avoided by

ensuring that there is maximum opportunity for them to self-identify and self-describe to the network.

Manual configuration also needs to be supported, for example where system parameters are subject to

operator policy choices.
5.2.4 Quality of monitoring

The system has to include mechanisms to monitor the health of modules and services and prevent

failures. Helpful alerts can then be provided to the people responsible for managing the system.

5.2.5 Maintainability

It is desirable to make on-board systems simple to maintain, through software updates, device

interrogation, problem diagnosis, etc. Remote monitoring and maintenance of IT systems is now

commonplace, but requires suitably designed communications access.

In the case of on-board systems, it is particularly important to be able to interrogate a system from a

convenient point on the vehicle, and to avoid the need to access or uninstall deeply-buried equipment.

5.2.6 Migration

Currently there already exist several IP and non-IP systems and different IT architecture in PT vehicles,

and it will not be practical to migrate them all to a fully-functional IP network immediately. Therefore,

the architecture has to allow for the gradual roll-out of new modules and services onto an IP backbone,

while still enabling the inclusion of proprietary systems while they remain important operational

components. This raises interoperability challenges and would imply the need for some kind of gateway

access and data translation.
5.2.7 Supporting fleet changes

Vehicles will typically be liable to change the service they are running, which alters the way in which

they need to be integrated into the operator’s control systems. This includes a number of special cases,

such as:
— where an operator “shares” a vehicle with another operator during operation;

— where an operator uses the same vehicle for several authorities, during the same day.

Operators/authorities may therefore need to operate fleets of vehicles using different IT architectures

or systems. These again emphasize the need for the on-board systems and networks to be secure,

configurable and adaptable.
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6 Network architecture
6.1 Introduction

This clause describes the on-board IP network and the technical mechanisms to be used to connect

modules to it. It covers IP addressing, name registration and resolution, communication protocols and

communication methods.
6.2 Network overview

Each vehicle shall have a private IP network (the “primary on-board IP network” or just “primary

network”) to interconnect modules. This should be provide the primary means by which modules

exchange data within the vehicle level, and by which the modules share common resources.

Modules on the network may be connected physically (as described in CEN/TS 13149-8) or virtually

over IP media.
6.3 Gateways to other networks

Beside the primary network, a vehicle may have several other communication networks (which may or

may not be IP-based). A typical example would be the automotive CAN (Controller Area Network); there

may also be serial buses like RS485; and there could be a wireless network (perhaps WiFi) for

passenger access.

Such networks (“external networks”) may be connected to the primary network. Such connections,

where they exist, shall be via suitably secure gateways.

Figure 2 shows an example overview of a generic on board IP network, with an external network and

gateway allowing exchange of data between external and primary networks.
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Key
M1 – M5 Hardware modules
M51 and M52 Virtual modules (hosted by hardware module M5)
M6 Module providing a gateway
IP Primary network
N Other on board network
Figure 2 — A generic on board system with an external network
6.4 IP addressing
6.4.1 General addressing considerations

Each module needs to have an IP address on the network. To fulfil the requirement of an easy

configuration, automatic mechanis
...

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