In Pays de la Loire, ielo dark fiber supports higher education and research: insights from SIEN

Paris, 22 October 2026– Accessing computing resources remotely, transferring large volumes of data between institutions or attending lectures delivered from another city: all these activities rely on infrastructure capable of transporting growing volumes of data quickly and reliably.

Since 2023, the Nantes–Angers dark fiber link, provided by ielo, a neutral and independent nationwide network infrastructure operator, has formed one of the key routes of the Pays de la Loire Regional High-Speed Network for Higher Education and Research (RRTHD-ESR-PDLL).

Shared infrastructure across Pays de la Loire

Operated by the Service Inter-Établissement Numérique (SIEN), established by Nantes Université, the University of Angers and Le Mans Université, the regional network serves eight university cities: Nantes, Angers, Le Mans, Cholet, Saumur, Saint-Nazaire, La Roche-sur-Yon and Laval.

It connects participating institutions to RENATER, France’s national research and education network, as well as to regional digital resources. Its purpose is to facilitate the sharing of resources essential to higher education and research, while ensuring consistent service levels, a coherent network architecture and comprehensive coverage across the academic region.

120 km of dark fiber to retain control over network infrastructure

To build an infrastructure capable of evolving over the long term, SIEN opted for dark fiber. Following a public tender process, ielo was selected to provide and maintain 120 km of dark fiber between Nantes and Angers, a key route within the regional network.

To deliver this service, ielo draws on its backbone network spanning more than 12,000 km along France’s major motorway corridors, complemented by over 22,000 km of metropolitan networks.

Unlike a managed bandwidth service, this solution gives SIEN access to dedicated passive optical infrastructure provided and maintained by ielo, over which it deploys its own transmission equipment. SIEN’s teams therefore retain control over network capacity and the evolution of their network architecture.

Using advanced optical transport technologies, including coherent DWDM and OTN, SIEN can now operate at up to 400 Gb/s per wavelength on this route, supporting bandwidth-intensive digital applications.

“This project is a clear illustration of ielo’s role: providing our customers and partners with optical infrastructure they can truly use as their own. Whatever the required service model – shared bandwidth (LAN-to-LAN), dedicated bandwidth (Wave) or dedicated infrastructure (dark fiber) – ielo delivers the infrastructure its customers need, giving them maximum flexibility,” explains Hélios de Creisquer, Chief Technology Officer at ielo.

ielo delivered the service on schedule and in accordance with SIEN’s technical requirements. The operator has in-house expertise covering the key stages of network design, deployment and operation, including network engineering, design and planning teams, field engineers based across 12 Regional Technical Centres, and network monitoring through its Network Operations Centre (NOC).

From route knowledge and infrastructure documentation to the coordination of maintenance interventions, the entire service delivery and operational process is managed by ielo’s teams.

“We chose dark fiber to retain control over our network and ensure we could evolve it as our needs change. On the Nantes–Angers route, the quality of the fiber provided by ielo meets the technical requirements of our architecture, particularly in terms of optical power budget, attenuation and polarisation mode dispersion (PMD). The maintenance and operational support provided by ielo are particularly effective, and its technical support team stands out for its consistently high availability and reliability,” says Thierry Oger, Vice-President for Digital Affairs at the University of Angers and Technical Director of the RRTHD-ESR-PDLL regional network.

Scaling network capacity as digital needs evolve

Artificial intelligence, inter-data centre connectivity, large-scale data storage and mission-critical applications: the RRTHD-ESR-PDLL brings digital resources closer to their users while enabling infrastructure to be shared across the region.

Researchers can remotely access regional computing centres to carry out work requiring significant computing resources, particularly in scientific computing.

The network also facilitates the sharing of teaching resources across university campuses. Since the start of the 2026 academic year, second-year medical students at the University of Angers have been able to attend live lectures delivered from the Faculty of Health in Angers while studying at sites in Le Mans or Laval.

Three years after entering service, the Nantes–Angers route demonstrates the value of dark fiber backed by infrastructure managed and maintained by a network operator. It enables SIEN to scale capacity in line with its needs while combining control over its network architecture with reliable operations.

More broadly, the SIEN project reflects the changing digital infrastructure requirements of major public-sector organisations. Growing data volumes, the sharing of resources across multiple sites and the need for greater network sovereignty are placing increasing demands on capacity, scalability and infrastructure control.

Already working alongside organisations such as RENATER and RECIA in the Centre-Val de Loire region, ielo supports this evolution by bringing its optical infrastructure and network engineering expertise to projects requiring dedicated, scalable and reliably managed optical routes over the long term.

About SIEN

The Service Inter-Établissement Numérique (SIEN) was established in early 2022 to support higher education and research institutions across Pays de la Loire.

Its mission is to enable the regional sharing of network infrastructure, data centre infrastructure and application services.

Hosted by Nantes Université, its founding members are Nantes Université, the University of Angers and Le Mans Université.

SIEN works in direct partnership with GLICID, the regional high-performance computing centre serving higher education and research institutions.