HPC In Focus Magazine Network

GÉANT and the NRENs ready for the demands of EuroHPC

On 21 September 2022, Sebastiano Buscaglione, Senior Network Architect and member of the GÉANT Network Evolution team, observed a significant increase in traffic on one of GÉANT’s backbone trunk links between Geneva and Milan.

Upon investigation, he discovered that the traffic was coming from ARNES, the Slovenian NREN, which is connected to a GÉANT router in Ljubljana, Slovenia. A review of their traffic graph revealed a sharp increase in traffic from 20Gbps in May 2021 to over 150Gbps in September 2022.

Most of the traffic was going over the LHCONE VRF (virtual routing and forwarding) and the increase in traffic was sudden, starting around May 2021, as shown in the graph below:

Slovenian NREN traffic graph
Slovenian NREN traffic graph

We found out the reason for the sharp increase while attending the LHCONE meeting in October 2022 at CERN. During a presentation on behalf of the ATLAS experiment, David Cameron of the University of Oslo presented the following graph:

ATLAS Compute Resource Usage – last 2 years
ATLAS Compute Resource Usage – last 2 years

The ATLAS experiment – a collaboration involving 181 institutions across 42 countries and therefore one of the largest collaborative projects in scientific history – significantly increased its use of High-Performance Computing (HPC) around the time the team observed an increase in traffic, as shown in the graph above. The circle in the graph illustrates the start of a significant and sustained increase in the usage of HPC resources, represented by the light blue colour.

According to David Cameron, the experiment began using the Vega EuroHPC, a Petascale supercomputer located in Slovenia, and ATLAS was one of the first users of this facility – in this case by collaborators primarily in the Nordic region.

Research and Education networks such as GÉANT, together with NORDUnet and the NRENs, play a critical role in enabling researchers to access and utilise advanced facilities like the Vega EuroHPC supercomputer. In his presentation, David Cameron emphasised the importance of the network in supporting the successful operation of the ATLAS collaboration, describing it as a rock-solid, highly reliable building block”.

He further added that the network has been a key element in the distributed computing infrastructure and has performed exceptionally well, however we must ensure that it continues to do so in the future. The slides from Cameron’s presentation are available online.

As the use of advanced research facilities increases and new users begin to utilise them, it is expected that there will be a corresponding increase in traffic demands on research and education networks. These networks, including GÉANT, play a crucial role in supporting the research and education community in accessing and utilising valuable resources.

Indeed, as we see new supercomputers coming online and being built in Europe as part of the EuroHPC initiative, this scenario will become more commonplace: that of advanced supercomputers downloading data from remote locations, very likely interconnected by Europe’s NRENs, in order to feed their computation.

To meet these evolving needs of its users, GÉANT is upgrading all layers of its network. This includes the expansion of the GÉANT fibre network, which is set to triple in length, bring a five-fold increase in speed, and connect roughly double the number of countries compared to 2018. Additionally, the optical line system is being replaced with a disaggregated system, which allows for a more cost-effective transmission network. The tender for the renewal of the packet layer will be concluded in early 2023, with the rollout of the next-generation GÉANT packet layer beginning at the end of 2023. To learn more about these efforts, you can check out our previous blog post “The next generation GÉANT network – a revolution in technology and funding”.

Further reading

GÉANT CONNECT 42 - A new era for digital innovationThis article is featured on CONNECT42, the latest issue of the GÉANT CONNECT Magazine!

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