RENATER and the CNRS are preparing to transfer data from the HL-LHC

Designed to validate the operation and capacity of the network and software infrastructure required to process the data generated by the future HL-LHC (High Luminosity Large Hadron Collider), an initial large-scale test was carried out globally at the end of February. In France, the National Telecommunications Network for Technology, Education and Research (RENATER) and the IN2P3 Computing Centre (CNRS – National Institute for Nuclear and Particle Physics) have confirmed that the national network infrastructure is capable of handling the expected data throughput.

The High-Luminosity Large Hadron Collider (HL-LHC) is a major upgrade to CERN’s Large Hadron Collider (LHC)[1], the world’s largest particle accelerator, designed to test the Standard Model of particle physics. Whilst the LHC has, for example, already led to the discovery of a new elementary particle, the Higgs boson, the HL-LHC project aims to push the LHC’s performance to its limits in order to increase the potential for discoveries from 2029 onwards. The detectors installed on the collider will therefore undergo significant upgrades, resulting in the generation of even more data.

The LHC’s data processing infrastructure comprises several hundred sites spread across the globe and is organised into several tiers. At the heart of this computing grid, CERN distributes the data to fourteen international Tier 1 centres, which in turn feed a second tier (Tier 2) comprising around 160 sites spread across the globe.

With this development of the LHC, it is essential to adapt the data transfer capacity between the various sites of this computing infrastructure in order to handle the significant increase in data generated by the HL-LHC. Known as the ‘data challenge’, the test carried out at the end of February by all first-tier sites aimed to validate the software and the performance of the data storage systems, and to test the various inter-site network links deployed around the world, whether dedicated to LHCONE, LHCOPN[2], or shared with other uses

In France, the RENATER network provides this transport infrastructure to CC-IN2P3, a major player in scientific computing for the analysis of data from large-scale physics experiments and a Tier 1 site for the LHC. To ensure the success of this data challenge, in early 2024 RENATER increased CC-IN2P3’s connectivity dedicated to the LHC from 200 to 400 Gbit/s. RENATER’s connectivity to the European GÉANT network has also been upgraded to a total capacity of 800 Gbit/s.

Whilst the results of the data transfer tests conducted during the LHC experiments are currently being analysed, preliminary observations of network performance during the exercise have already revealed sustained data rates of 200 Gbit/s on LHCOPN and 200 Gbit/s on LHCONE, running in parallel for several hours – a very promising sign for the future.

This optimal utilisation of the dedicated network links for LHC experiments – which currently accounts for just 25% of the capacity targeted for the HL-LHC by 2029 – is excellent news for the rollout of this infrastructure in the coming years.

“As the demands of the Institute’s major scientific programmes grow, CC-IN2P3 must ensure the highest possible quality of data transfer, which requires a steady increase in connectivity speeds”, explains Pierre-Étienne Macchi, Director of CC-IN2P3. “This test was therefore an important first step in the evolution of the performance of the HL-LHC data processing infrastructure.”

Boris Dintrans, Managing Director of GIP RENATER, explains: “RENATER has been serving the French scientific community and helping to promote its reputation for over 30 years. As part of the preparations for the computing infrastructure required to process future HL-LHC data, this data challenge has enabled us to validate, together with our colleagues at the CNRS, the capabilities and robustness of our network to best support this world-class project.”

[1] Based in Geneva (Switzerland), CERN is the European Organisation for Nuclear Research.

[2] LHCOPN connects CERN with the first-tier processing centres, whilst LHCONE extends this connectivity to second- and third-tier sites.