Tuesday 2 October 2012

2012 successful update of the International GSM-R Overlay Network

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GSM-R is the railway digital radio system in Europe – a main component of the ERTMS – enforced by European law. 154,000 km of track are planned to be covered with GSM-R, of which more than 70,000 km are already in operation.

As for the GSM-R mobile stations statistics in Europe, over 40,000 cab radios, 2,500 EDORs (ETCS Data Radio) and more than 120,000 handhelds are reported to be activated.
These figures show GSM-R’s increasing importance in international train traffic. As an example, this is reflected in an expanding number of international trains on the ETCS L2 equipped part of Corridor A from Rotterdam-Genoa. These trains can only operate when GSM-R roaming services are continuously available.
All GSM-R networks are interconnected in order to facilitate borderless GSM-R usage for all train operators. This interconnection network is called the ‘international GSM-R overlay network’.

The GSM-R network operators coordinate network development, roaming services and harmonisation of GSM-R border crossing in the UIC Working Groups for GSM-R Network Management (NMG) and European Network Integration for Railways (ENIR).
As seen on the map, 12 European railways are interconnected, with 25 direct interconnections and more than 26 end-to-end roaming agreements in operation.
Since GSM-R network implementation in Europe is a continuous process, each new implementer, when activating its network, expects that roaming will be possible. This results in an expanding interconnection network with regular updates of GSM-R signalling & traffic routing facilities.

The NMG/ENIR have adopted the strategy of a yearly upgrade of the interconnection network, in order to include “newcomers” in this network and to make it possible to interconnect with a second geo-redundant node to archive a higher availability.
In order to carry out these upgrades in a well prepared and coordinated way, the Common Design Document (CDD) has been defined. This also covers the routing guidelines to build the individual Routing Data Sets (RDS) – establishing the main and alternate routes for the international GSM-R networks interconnection – based on the current physical network status. The RDS databases are calculated and generated by DB Systel GmbH, and are part of the UIC GSM-R Network Management Activity deliverables.

Changing an international RDS update (operation named “Big Bang”) has to be well synchronised in all GSM-R networks. With this approach the outage of routing facilities and impact for GSM-R users is minimised. In case of failing the update process in one country could affect GSM-R roaming facilities in all GSM-R networks, with impact on train operation. Hence, during the update process, a central coordinator is monitoring the progress.

This year the “Big Bang” took place on 23 September 2012, 4 am, CEST (Central European Summer Time). The whole operation was successful and on schedule, thanks to perfect preparation and coordination, with just some minor issues which were solved within a few days. There was no impact on train operation at all.

This operation is considered to be a great achievement. It demonstrates that the “Big Bang” approach is the right one and that the GSM-R networks are proven to be integrated and well managed all over Europe, the basis of the required interoperability.

For further information please contact Dan Mandoc, Railway Telecoms – ERIG Chairman: mandoc@uic.org, Dirk Brucks, Chairman ENIR: Dirk.Brucks@deutschebahn.com
and Chiel Spaans, Chairman NMG: Chiel.Spaans@prorail.nl

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