EN 61375-2-5:2015

Electronic railway equipment - Train communication network (TCN) - Part 2-5: Ethernet train backbone

IEC 61375-2-5:2014 defines Ethernet Train Backbone (ETB) requirements to fulfil open train data communication system based on Ethernet technology. Respect of this standard ensures interoperability between local Consist subnets whatever Consist network technology (see IEC 61375-1 for more details). All Consist network definitions should take into account this standard to preserve interoperability. This standard may be additionally applicable to closed trains and multiple-unit trains when so agreed between purchaser and supplier.

Elektronische Betriebsmittel für Bahnen - Zug-Kommunikations-Netzwerk (TCN) - Teil 2-5: Ethernet Train Backbone

Matériel électronique ferroviaire - Réseau embarqué de train (TCN) - Partie 2-5: Réseau central de train Ethernet

L'IEC 61375-2-5:2014 définit les exigences de réseau central de train Ethernet (ETB) pour satisfaire au système de communication de données d'un train à composition variable, basé sur la technologie Ethernet. Le respect de la présente norme assure l'interopérabilité entre les sous-réseaux de rames locales, quelle que soit la technologie de réseau de rame (voir l'IEC 61375-1 pour plus de détails). Il convient que toutes les définitions portant sur les réseaux de rames tiennent compte de la présente norme afin de préserver l'interopérabilité. La présente norme peut également s'appliquer aux rames non modifiables et aux trains de rames multiples après accord entre acheteur et fournisseur.

Železniške elektronske naprave - Hrbtenično omrežje vlaka - 2-5. del: Ethernetno hrbtenično omrežje vlaka

Ta del standarda IEC 61375 določa zahteve za ethernetno hrbtenično omrežje (ETB) za podatkovno komunikacijski sistem odprtega vlaka na osnovi tehnologije Ethernet.
Spoštovanje tega standarda zagotavlja interoperabilnost med lokalnimi podomrežji Consist in drugimi omrežnimi tehnologijami Consist (glej standard IEC 61375-1 za več podrobnosti).
Za ohranjanje interoperabilnosti naj bi vse opredelitve omrežja Consist upoštevale ta standard. Ta standard se lahko uporablja tudi za zaprte vlake in vlake z večdelnimi enotami, če se o tem dogovorita kupec in dobavitelj.

General Information

• Status: Published
• Publication Date: 26-Feb-2015
• Withdrawal Date: 28-Sep-2017
• ICS: 45.060 - Railway rolling stock
• Technical Committee: CLC/TC 9X - Electrical and electronic applications for railways
• Drafting Committee: IEC/TC 9 - IEC_TC_9
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 27-Feb-2015
• Completion Date: 27-Feb-2015
• Directive: 2008/57/EC - Directive 2008/57/EC of the European Parliament and of the Council of 17 June 2008 on the interoperability of the rail system within the Community (Recast)
• Mandate: M/483 - Mandate for programming and standardisation addressed to the European standardisation bodies under directive 2008/57/EC in the field of the interoperability of the rail system within the European Union
• Ref Project: SIST EN 61375-2-5:2015 - Electronic railway equipment - Train backbone - Part 2-5: Ethernet Train Backbone

Overview

EN 61375-2-5:2015 (IEC 61375-2-5:2014) defines the Ethernet Train Backbone (ETB) for the Train Communication Network (TCN). The standard specifies requirements for an open, interoperable train data communication system based on Ethernet technology so local Consist subnets-regardless of their internal Consist network technology-can interoperate across the train. It is applicable to conventional trains and, by agreement, to closed trains and multiple-unit trains.

Key topics and technical requirements

• ETB physical layer - Defines physical characteristics for intra-car, inter-car and inter-Consist links, and addresses connector and cabling considerations relevant to railway environments.
• Power over Ethernet (PoE) - Considers PoE usage on the ETB where applicable for powering devices.
• Physical architecture & redundancy - Specifies topology options, link aggregation and redundancy strategies to maintain availability on the train backbone.
• Data link layer - Covers switch behavior and Ethernet bridging relevant to ETB operation.
• Network layer (IPv4 subnets) - Provides IP mapping rules, train subnet definitions, a global IPv4 address space approach, multicast group addressing and detailed IP address mapping for ETB hosts and nodes.
• Transport layer and services - Describes transport considerations relevant to train data exchange (protocol guidance is included).
• ETB node concepts (ETBN) - Defines the Ethernet Train Backbone Node roles, addressing, and host placement within train subnets.
• Train Inauguration (TTDP) - Specifies the Train Topology Discovery Protocol (TTDP) for ETB inauguration: topology discovery, HELLO/TOPOLOGY messages, peer detection, switch port states and required data structures (connectivity vectors, ETBN vectors).
• Routing & multicast management - Covers dynamic routing considerations for unicast and multicast across the train backbone.
• Environmental and EMC references - Normative references ensure ETB design aligns with railway EMC and connector/cabling standards.

Applications and users

• Rolling stock manufacturers - Implement ETB architectures for new vehicles to ensure interoperable communication across consists.
• System integrators & vehicle designers - Use the standard to define backbone topology, IP addressing and redundancy for onboard networks.
• Railway operators & fleet owners - Adopt EN 61375-2-5 to achieve interoperability across multiple suppliers and for lifecycle maintenance.
• Component suppliers (switches, cabling, PoE devices) - Ensure product compliance with ETB physical and data-link requirements.
• Signalling and onboard systems engineers - Integrate safety-relevant and passenger systems over an interoperable Ethernet backbone.

Related standards

• IEC 61375-1 (TCN general architecture) - overarching TCN concepts and consistency with Consist networks.
• IEC 61375-3-4 (Ethernet Consist Network) - Consist-level Ethernet definitions.
• IEEE 802.1 / IEEE 802.3 family - Bridging, link aggregation and Ethernet PHY references.
• IEC 61156 series, IEC 61076-2-101 - Cable and connector specifications used by ETB.

Keywords: EN 61375-2-5, Ethernet Train Backbone, ETB, Train Communication Network, TCN, IEC 61375-2-5, ETBN, train Ethernet, IPv4 subnets, TTDP, interoperability.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2015
äHOH]QLãNHHOHNWURQVNHQDSUDYH+UEWHQLþQRRPUHåMHYODNDGHO(WKHUQHWQR
KUEWHQLþQRRPUHåMHYODND
Electronic railway equipment - Train backbone - Part 2-5: Ethernet Train Backbone
Elektronische Betriebsmittel für Bahnen - Zug-Kommunikations-Netzwerk - Teil 2-5: ETB
- Ethernet Train Backbone
Matériel électronique ferroviaire - Réseau de train - Partie 2-5: Réseau de Train Ethernet
Ta slovenski standard je istoveten z: EN 61375-2-5:2015
ICS:
45.020 Železniška tehnika na Railway engineering in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 61375-2-5

NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2015
ICS 45.060
English Version
Electronic railway equipment - Train communication network
(TCN) - Part 2-5: Ethernet train backbone
(IEC 61375-2-5:2014)
Matériel électronique ferroviaire - Réseau embarqué de Elektronische Betriebsmittel für Bahnen - Zug-
train (TCN) - Partie 2-5: Réseau central de train Ethernet Kommunikations-Netzwerk - Teil 2-5: ETB - Ethernet Train
(IEC 61375-2-5:2014) Backbone
(IEC 61375-2-5:2014)
This European Standard was approved by CENELEC on 2014-09-29. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61375-2-5:2015 E
Foreword
The text of document 9/1933/FDIS, future edition 1 of IEC 61375-2-5, prepared by IEC/TC 9 "Electrical
equipment and systems for railways" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 61375-2-5:2015.
The following dates are fixed:
(dop) 2015-08-27
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2017-09-29
standards conflicting with the
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.
Endorsement notice
The text of the International Standard IEC 61375-2-5:2014 was approved by CENELEC as a European
Standard without any modification.
IEC 61375-2-1:2012 NOTE  Harmonized as EN 61375-2-1:2012.
IEC 61784-2 NOTE  Harmonized as EN 61784-2.
IEC 61918 NOTE  Harmonized as EN 61918.

- 3 - EN 61375-2-5:2015
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD

applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 61076-2-101 2012 Connectors for electronic equipment - EN 61076-2-101 2012
Product requirements -- Part 2-101: Circular
connectors - Detail specification for M12
connectors with screw-locking
IEC 61156 series Multicore and symmetrical pair/quad cables - series
for digital communications
IEC 61156-1 2007 Multicore and symmetrical pair/quad cables - -
for digital communications - Part 1: Generic
specification
IEC 61156-5 -  Multicore and symmetrical pair/quad cables - -
for digital communications - Part 5:
Symmetrical pair/quad cables with
transmission characteristics up to 1 000
MHz - Horizontal floor wiring - Sectional
specification
IEC 61375-1 2012 Electronic railway equipment - Train EN 61375-1 2012
communication network (TCN) -- Part 1:
General architecture
IEC 61375-2-3 -  Electronic railway equipment - Train FprEN 61375-2-3 -
Communication Network (TCN) - Part 2-3:
TCN communication profile
IEC 61375-3-4 -  Electronic railway equipment - Train Bus - EN 61375-3-4 -
Part 3-4: ECN - Ethernet Consist Network
IEC 62236-3-2 -  Railway applications - Electromagnetic - -
compatibility -- Part 3-2: Rolling stock -
Apparatus
ISO/IEC 7498 series Information processing systems - Open - series
systems interconnection - Basic reference
model
ISO/IEC 8824 series Information technology - Abstract Syntax - series
Notation One (ASN.1)
ISO/IEC 9646 series Information technology - Open Systems EN ISO/IEC 9646 series
Interconnection
ISO/IEC 11801 2002 Information technology - Generic cabling for - -
customer premises
IEEE 802.1AB -  IEEE Standard for Local and Metropolitan - -
Area Networks - Station and Media Access
Control Connectivity Discovery
IEEE 802.1AX 2008 IEEE Standard for Local and metropolitan - -
area networks - Link Aggregation

IEEE 802.1D 2012 IEEE Standard for local and metropolitan - -
area networks - Media Access Control
(MAC) Bridges
IEEE 802.1Q -  IEEE Standard for Local and metropolitan - -
area networks - Media Access Control
(MAC) Bridges and Virtual Bridges
IEEE 802.2 -  IEEE Standard for Information technology - - -
Telecommunications and information
exchange between systems - Local and
metropolitan area networks - Specific
requirements - Part 2: Logical Link Control
IEEE 802.3 2012 IEEE Standard for Ethernet - -

- 5 - EN 61375-2-5:2015
Annex ZZ
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 2008/57/EC

This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and within its scope the standard covers all
relevant essential requirements as given in Annex lll of the EC Directive 2008/57/EC (also named as
New Approach Directive 2008/57/EC Rail Systems: Interoperability).

Once this standard is cited in the Official Journal of the European Union under that Directive and has
been implemented as a national standard in at least one Member State, compliance with the
clauses of this standard given in Table ZZ.1 relating to the ‘rolling stock - locomotives and
passenger rolling stock’ subsystem of the rail system in the European Union, confers, within the
limits of the scope of this standard, a presumption of conformity with the corresponding Essential
Requirements of that Directive and associated EFTA regulations.

Table ZZ.1 - Correspondence between this European Standard, the RST LOC&PAS TSI
(published in the Official Journal L 356 on 12 December 2014, p. 228) and Directive
2008/57/EC
Clauses of this Chapter / § / points / Essential Comments
European Standard of RST LOC&PAS TSI Requirements (ER) of
Directive 2008/57/EC
2. Requirements specific
4.2.4.9 Brake state and
to each sub-subsystem
fault indication
2.4. Rolling Stock
The TSI does not impose
4.2.5.2 Audible 2.4.1. Safety
any technical solution
communication system
regarding physical
2.4.2. Reliability
interfaces between units.
and availability
4.2.5.3 Passenger alarm
2.4.3. Technical
The whole standard is The standard offers a
4.2.5.4 Communication
compatibility
applicable
general multi-purpose
devices for passengers
solution for the inter-
4.2.5.5 Exterior doors
vehicle digital
communication network
4.2.12.2 General
and it is relevant to
documentation: -
vehicle interoperability.
description of
computerised onboard
systems
WARNING: Other requirements and other EU Directives may be applicable to the products

falling within the scope of this standard.

IEC 61375-2-5 ®
Edition 1.0 2014-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electronic railway equipment – Train communication network (TCN) –

Part 2-5: Ethernet train backbone

Matériel électronique ferroviaire – Réseau embarqué de train (TCN) –

Partie 2-5: Réseau central de train Ethernet

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XF
CODE PRIX
ICS 45.060 ISBN 978-2-8322-1772-6

– 2 – IEC 61375-2-5:2014 © IEC 2014
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references. 10
3 Terms, definitions, symbols, abbreviations and conventions . 11
3.1 Terms and definitions . 11
3.2 Symbols and abbreviations . 15
3.3 Conventions . 17
3.3.1 Base of numeric values . 17
3.3.2 Naming conventions . 17
3.3.3 State diagram conventions . 17
3.3.4 Annotation of data structures . 17
4 ETB physical layer . 17
4.1 Train regions . 17
4.2 Physical characteristics . 18
4.2.1 General . 18
4.2.2 Intra car physical layer . 18
4.2.3 Inter car physical layer . 20
4.2.4 Inter Consist physical layer . 24
4.3 Power over Ethernet (PoE) . 27
4.4 ETB physical architecture and redundancy. 29
4.4.1 General . 29
4.4.2 Link aggregation architecture . 29
4.4.3 Functions . 31
5 ETB data link layer . 32
6 ETB network layer: IPv4 subnets definition . 33
6.1 General . 33
6.2 IP mapping introduction . 34
6.3 Topology . 34
6.3.1 General . 34
6.3.2 Closed train . 35
6.4 Network IP address map . 36
6.4.1 Global IPv4 address space . 36
6.4.2 Train subnet definition . 36
6.4.3 Train IP address map summary . 40
6.4.4 Train IP group addresses (multicast) . 41
6.5 Particular hosts IP addresses . 41
6.5.1 ETBN (Ethernet Train Backbone Node) . 41
6.5.2 Hosts on train subnet . 42
6.5.3 Host inside a closed train . 43
6.6 Some use cases . 45
6.7 Dynamic IP routing management . 48
6.7.1 Unicast routes . 48
6.7.2 Multicast routes . 48
7 ETB Transport layer . 49
8 ETB Train Inauguration: TTDP . 50

IEC 61375-2-5:2014 © IEC 2014 – 3 –
8.1 Contents of this clause . 50
8.2 Objectives and assumptions . 50
8.2.1 Goals . 50
8.2.2 Out of scope . 51
8.2.3 Assumptions . 51
8.3 ETBN settings . 52
8.3.1 ETB switch port states . 52
8.3.2 Node settings . 52
8.4 General behaviour . 54
8.5 ETBN Inauguration state diagram . 54
8.5.1 General . 54
8.5.2 Actions . 55
8.5.3 Transitions . 57
8.6 ETBN peers discovery . 58
8.6.1 Internal peers detection . 58
8.6.2 External peers detection . 58
8.6.3 Switch port states handling. 59
8.6.4 ETB lines statuses . 59
8.7 TTDP messages description . 61
8.7.1 General . 61
8.7.2 Convention . 61
8.7.3 TTDP frame tagging . 61
8.7.4 Transport and addressing . 61
8.7.5 TTDP HELLO frame . 62
8.7.6 TTDP TOPOLOGY frame . 66
8.8 TTDP data structures . 72
8.8.1 Connectivity Vector . 72
8.8.2 ETBN Vector . 73
8.8.3 Connectivity Table . 73
8.8.4 Connectivity Table CRC . 74
8.8.5 Train network directory . 76
8.8.6 Train network directory CRC (Topology Counter) . 78
8.8.7 Corrected topology . 78
8.9 TTDP frames timing . 79
8.9.1 TTDP HELLO . 79
8.9.2 TTDP TOPOLOGY . 81
8.10 Inauguration Train Application interface . 83
8.11 Degraded modes . 83
8.11.1 Late insertion ETBN . 83
8.11.2 Losing ETBN . 84
8.11.3 End ETBN failure and partial topology counter . 84
8.12 Some discovery timing . 85
8.12.1 ETBN wakeup . 85
8.12.2 ETBN failure . 86
8.12.3 Consist coupling . 87
9 ETB ETBN redundancy . 88
10 ETB physical train naming convention (optional) . 89
10.1 General . 89
10.2 ETB Train domain . 89

– 4 – IEC 61375-2-5:2014 © IEC 2014
10.3 Hostname . 90
11 ETB Quality of Service . 91
11.1 Contents of this clause . 91
11.2 Frame forwarding . 91
11.2.1 ETBN switching rate . 91
11.2.2 No Head-of-Line blocking . 91
11.2.3 Switching priorities . 91
11.2.4 Switching queuing scheme . 92
11.3 Priority of Inauguration frames . 92
11.4 ETB ingress rate limiting . 92
11.5 ETB egress rate shaping . 92
11.6 ETB data classes . 92
12 ETB Management and monitoring . 93
13 ETB Application interface . 93
13.1 Contents of this clause . 93
13.2 Abstract communication model . 93
13.3 ETB Process Data and Message Data protocols . 94
13.4 ETB protocol transparency . 94
13.5 ETBN interfaces . 94
13.5.1 Application . 94
13.5.2 Maintenance and monitoring . 95
14 ETB conformity statement . 96
Annex A (normative) Summary of ETB sizing parameters. 97
Annex B (normative) Physical topology building algorithm . 98
Annex C (normative) TTDP MIB definition . 101
Bibliography . 121

Figure 1 – ETB train regions . 18
Figure 2 – ETB Inter car at same potential . 23
Figure 3 – ETB Inter car not at the same potential . 24
Figure 4 – ETB Consist reversing . 26
Figure 5 – ETB Inter Consist segment . 27
Figure 6 – ETBN PSE PoE use case . 27
Figure 7 – ETBN PD PoE use case . 28
Figure 8 – PoE in inter-Consist. 28
Figure 9 – PoE PSE alternative A . 29
Figure 10 – Redundant train backbone architecture . 29
Figure 11 – Link aggregation model . 30
Figure 12 – Link aggregation group . 31
Figure 13 – Conversations over LAG . 31
Figure 14 – Hierarchical Consist topology . 35
Figure 15 – Closed train . 36
Figure 16 – "Subnet Id" with single Consist Network . 38
Figure 17 – "Subnet Id" with two single Consist Networks . 38
Figure 18 – Multiple Consist Networks, without fault tolerance . 39

IEC 61375-2-5:2014 © IEC 2014 – 5 –
Figure 19 – "Subnet Id" with ETBN redundancy . 39
Figure 20 – "Subnet Id" in multiple units with ETBN redundancy . 40
Figure 21 – IP train address space summary . 40
Figure 22 – Relative addressing example . 45
Figure 23 – Train composed of a single Consist Network . 46
Figure 24 – Train composed of two single Consist Networks . 46
Figure 25 – Train composed of single Consist Network with ETBN redundancy . 47
Figure 26 – Train composed of two Consist Networks with ETBN redundancy . 47
Figure 27 – Train with two Consist Networks in single Consist . 48
Figure 28 – ETBN top node reference . 51
Figure 29 – ETBN orientation capability . 52
Figure 30 – ETB switch in passive bypass setting . 53
Figure 31 – ETB switch in intermediate setting . 53
Figure 32 – ETB switch in End Node Setting . 54
Figure 33 – ETBN Inauguration state diagram . 55
Figure 34 – Switch port state diagram . 59
Figure 35 – ETBN physical line state machine . 60
Figure 36 – TTDP HELLO frame LLDPDU structure . 62
Figure 37 – LLDP organizationally TLV structure . 62
Figure 38 – TTDP HELLO frame structure . 66
Figure 39 – TTDP specific HELLO TLV structure . 66
Figure 40 – TTDP TOPOLOGY frame structure . 71
Figure 41 – TTDP TOPOLOGY specific ETB TLV structure . 72
Figure 42 – TTDP TOPOLOGY specific CN TLV structure . 72
Figure 43 – Train composition for TNDir example . 77
Figure 44 – TTDP HELLO normal mode and recovery timing . 80
Figure 45 – TTDP HELLO failure timing . 81
Figure 46 – TTDP TOPOLOGY frames handling . 82
Figure 47 – TTDP ETBNs wake up timing . 85
Figure 48 – TTDP ETBN failure timing . 86
Figure 49 – TTDP Consist coupling timing . 87
Figure 50 – Example of ETBN IP routing table without redundancy . 88
Figure 51 – Example of ETBN IP routing table with redundancy . 88
Figure 52 – ETB train domain defintion . 90
Figure 53 – Abstract communication model for ETB communication . 94
Figure B.1 – Physical topology building . 98
Figure C.1 – TTDP MIB tree view . 103

Table 1 – ETB Intra car physical layer interface . 19
Table 2 – ETB Inter car physical layer interface . 21
Table 3 – ETB Inter consist physical layer interface . 25
Table 4 – ETB Switch data link layer interface . 32
Table 5 – ETB OSI Network layer . 33

– 6 – IEC 61375-2-5:2014 © IEC 2014
Table 6 – Train subnet definition . 36
Table 7 – Train subnet decomposition . 37
Table 8 – Train IP group addresses reserved range . 41
Table 9 – ETBN ETB IP address . 42
Table 10 – Hosts IP on train subnet . 43
Table 11 – Application ED common interface . 50
Table 12 – ETB switch port states . 52
Table 13 – TTDP destination MAC addresses . 62
Table 14 – Connectivity Vector . 73
Table 15 – Connectivity Vector Fields . 73
Table 16 – ETBN Vector . 73
Table 17 – ETBN Vector Fields . 73
Table 18 – Connectivity Table . 74
Table 19 – Connectivity Table fields . 74
Table 20 – Train network directory . 76
Table 21 – Train network directory fields . 76
Table 22 – Train network directory (example) . 78
Table 23 – DSCP field mapping . 91
Table 24 – ETB Switching Priorities . 92
Table 25 – Train Topology Discovery Object . 95
Table A.1 – ETB sizing parameters . 97

IEC 61375-2-5:2014 © IEC 2014 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC RAILWAY EQUIPMENT –
TRAIN COMMUNICATION NETWORK (TCN) –

Part 2-5: Ethernet train backbone

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61375-2-5 has been prepared by IEC technical committee 9:
Electrical equipment and systems for railways.
The text of this standard is based on the following documents:
FDIS Report on voting
9/1933/FDIS 9/1961/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 8 – IEC 61375-2-5:2014 © IEC 2014
A list of all parts in the IEC 61375 series, published under the general title Electronic railway
equipment – Train communication network (TCN), can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
IEC 61375-2-5:2014 © IEC 2014 – 9 –
INTRODUCTION
IEC 61375-2-5 defines the Ethernet Train Backbone so as to achieve interoperability between
Consists of different types when coupled in the same train composition.
The standard follows the ISO-OSI model and specifies the whole protocols stack from the
physical layer up to the application layer.
A Protocol Implementation Conformance Statement (PICS) pro-forma allows suppliers to state
their conformity to this standard. The PICS pro-forma specification and the related conformity
test are not in the scope of this standard.

– 10 – IEC 61375-2-5:2014 © IEC 2014
ELECTRONIC RAILWAY EQUIPMENT –
TRAIN COMMUNICATION NETWORK (TCN) –

Part 2-5: Ethernet train backbone

1 Scope
This part of IEC 61375 defines Ethernet Train Backbone (ETB) requirements to fulfil open
train data communication system based on Ethernet technology.
Respect of this standard ensures interoperability between local Consist subnets whatever
Consist network technology (see IEC 61375-1 for more details).
All Consist network definitions should take into account this standard to preserve
interoperability.
This standard may be additionally applicable to closed trains and multiple-unit trains when so
agreed between purchaser and supplier.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61076-2-101:2012, Connectors for electronic equipment – Product requirements –
Part 2-101: Circular connectors – Detail specification for M12 connectors with screw-locking
IEC 61156 (all parts), Multicore and symmetrical pair/quad cables for digital communications
IEC 61156-1:2007, Multicore and symmetrical pair/quad cables for digital communications –
Part 1: Generic specification
IEC 61156-5, Multicore and symmetrical pair/quad cables for digital communications – Part 5:
Symmetrical pair/quad cables with transmission characteristics up to 1 000 MHz – Horizontal
floor wiring – Sectional specification
IEC 61375-1:2012, Electronic railway equipment – Train communication network (TCN) –
Part 1: General architecture
IEC 61375-2-3, Electronic railway equipment – Train communication network (TCN) –
Part 2-3: TCN communication profile (to be published)
IEC 61375-3-4, Electronic railway equipment – Train communication network (TCN) –
Part 3-4: Ethernet Consist Network (ECN)
IEC 62236-3-2, Railway applications – Electromagnetic compatibility – Part 3-2: Rolling stock
– Apparatus
ISO/IEC 7498 (all parts), Information technology – Open System Interconnection – Basic
Reference Model
IEC 61375-2-5:2014 © IEC 2014 – 11 –
ISO/IEC 8824 (all parts), Information technology – Abstract Syntax Notation One (ASN.1)
ISO/IEC 9646 (all parts), Information technology – Open Systems Interconnection –
Conformance testing methodology and framework
ISO/IEC 11801:2002, Information technology – Generic cabling for customer premises
IEEE 802.1AB, IEEE Standard for Local and metropolitan area networks – Station and Media
Access Control Connectivity Discovery
IEEE 802.1AX:2008, IEEE Standard for Local and metropolitan area networks – Link
Aggregation
IEEE 802.1D:2012, IEEE Standard for Local and metropolitan area networks – Media Access
Control (MAC) Bridges
IEEE 802.1Q, IEEE Standard for Local and metropolitan area networks – Virtual Bridged
Local Area Networks
IEEE 802.2, IEEE Standard for Information technology – Telecommunications and information
exchange between systems – Local and metropolitan area networks – Specific requirements –
Part 2: Logical Link Control
IEEE 802.3:2012, IEEE Standard for Information technology – Telecommunications and
information exchange between systems – Local and metropolitan area networks – Specific
requirements – Part 3: Carrier sense multiple access with collision detection (CSMA/CD)
access method and physical layer specifications
3 Terms, definitions, symbols, abbreviations and conventions
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
...