LRE architecture
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 LRE architecture 

WP2 Facilitating the take-up of a European Learning Resource Exchange

The LRE is a service that provides the means to unlock the educational content hidden in digital repositories across Europe and share it among all partners of the LRE and their users. The service is offered to actors providing digital content: Ministries of Education, regional educational authorities, commercial publishers, broadcasters, cultural institutions and other non-profit organisations who are offering extensive but heterogeneous catalogues and repositories of online content to schools.

From a technical standpoint, the LRE consists of an infrastructure based on a brokerage system to which independent systems (e.g., learning resource repositories, educational portals, learning (content) management systems) connect to share learning resources in a federated way. This architecture appears to be a good base on which collections of learning resources are made discoverable. It provides a good balance between trust and autonomy; it is decentralised enough to allow content providers to manage their collections autonomously, and secure enough to ensure the trust necessary when dealing with content for sensitive groups like pupils.

The LRE architecture

The LRE architecture

The figure above shows the LRE architecture. The backbone of the federation is a brokerage system, named “Limbs Is My Brokerage System” (LIMBS), to which repositories of learning resources and educational portals connect thanks to a client java library (depicted as a grey bar) that encapsulates the different networking protocols behind standard application programming interfaces (APIs). LIMBS and its client are released under the Lesser Gnu Public License (LGPL). The decision to open up the code of the brokerage system was motivated by the following considerations:

  • Foster adoption: An open source brokerage system guarantees the members of the federation that their integration efforts will not be lost. It gives them the possibility to influence the solution that they adopt and enough control over it to ensure its continuation.
  • Foster development: The involvement of a larger community of developers and public scrutiny of the source code shortens development time and improves the quality of the code and documentation produced. Moreover, the community helps to make sure the developments are in line with users’ requirements.
  • Promote the federated model outside the e-learning community, by encouraging the adoption of LIMBS by other communities (e.g., digital libraries).


Among the open source licences considered to release the code of LIMBS, LGPL was chosen because it allows both commercial systems and pure open source systems to use the client and join the federation.

The LRE Today

The current version of the LRE is connected to:

  • Repositories of resources from different EUN projects (myEurope, Insafe, Insight, Xplora, eTwinning, Celebrate),
  • A harvester that centralises metadata from 3 Austrian repositories,
  • The repository of the Polish portal Scholaris,
  • Trubar, a Slovenian repository hosted by the University of Ljubljana,
  • An Hungarian repository hosted by Apertus
  • An Estonian repository hosted by Tallinn University on behalf of the Tiger Leap foundation, and
  • A Lithuanian repository managed by the Ministry of Education.

By the end of of the project, about 20 learning content repositories were available in the LRE federation.