Can you imagine a supercomputer powerful enough to make accurate predictions of high-impact weather up to two weeks ahead, of large-scale patterns up to four weeks ahead, and even of global-scale anomalies up to a year ahead?

The new High-Performance Computing Facility (HPCF) of the European Centre for Medium Range Weather Forecast (ECMWF) is developed to do just that! A very ambitious goal that will only be reachable with the right level of computing power capability.


High-performance, low power, and scalable computer architectures are vital for the future of numerical weather predictions and the ECMWF’s HPCF is at the core of the centre’s operational and research activities.

For over 40 years, the data centre has been located in Reading, UK, but in June 2017 ECMWF Member States approved the proposal by the Italian Government, and the Emilia Romagna Region, to host the new data centre in Bologna, Italy. The move will bring much needed flexibility for future growth, allowing for the next generation of supercomputers that are expected to bring a tenfold increase in computing power.

The new data centre is being built on the site of the new “Tecnopolo di Bologna” campus, where unused buildings and the grounds of a former tobacco factory are being redeveloped. It is scheduled to be running from mid-2022, and represents a unique greenfield deployment opportunity to develop an infrastructure that is flexible enough to quickly adapt to ever-changing computing and telecommunications requirements.

However, this important relocation means moving the enormous amounts of data hosted in Reading to the new Bologna data centre, a task made possible by dedicated connectivity on the academic internet formed by the National Research and Education Networks and the GÉANT backbone.

ECMWF’s new data centre is hosted at the Tecnopolo di Bologna, Italy. This picture was taken at the inauguration in September 2021. © ECMWF.

From a technical perspective, the new network design will be state-of-the-art for medium and large-scale data centres with:





Considering weather forecast and predictions, the new supercomputer is expected to:

↳ Significantly improve forecasts of near-surface temperatures and winds;

↳ Allow better description of near-surface temperature in snow-covered areas;

↳ Issue extended-range forecasts daily rather than twice-weekly, which in turns will allow a better description of extreme events monthly;

↳ And finally, in the long-term, combining advanced high-performance computing, big data and AI methodologies will allow to create a digital twin of the Earth with a breakthrough in realism.


ECMWF’s new HPC will rely on long distance data transfers for operations during the migration of the archive system. GÉANT was therefore brought in to conduct a series of end-to-end network performance tests and simulations which were done between August 2020 and March 2021.

Testing long-haul transfers is a vital aspect in the solution delivery process as they are often less predictable than data transfers over Local Area Networks (LANs). This happens mainly because the data must pass through many devices that are administered by multiple parties and many other data flows are involved. Physics also plays a part, as longer transfer distances introduce a substantial latency. Internet protocol limitations also need to be considered. Therefore, testing is the only empirical way to assess the functionality and performance level of the system as well as its reliability.

To conduct testing in a timely and effective way, ECMWF enlisted the help of Dr Richard Hughes-Jones, end-to-end network performance expert from GÉANT. Dr Hughes-Jones advised on how to best configure the test servers and carried out the bulk of the tests.

The initial tests were carried out with two servers connected directly to each other (“back-to-back”) – this established a “baseline” against which the performance of “real” long-distance connections could be measured. Some tests were also made using GÉANT test servers (the data transfer nodes, DTNs), first in London and then in Paris. These were useful, as they gave an idea of how an increase in latency (c. 9ms London, c. 16ms Paris) would affect the performance.

However, in order to emulate a data transfer with a similar latency like the one between Reading and Bologna, GÉANT configured a bespoke network path, which allowed the traffic from Reading to flow to Paris via an indirect, artificially longer path, traversing routers in Amsterdam, Frankfurt, and Geneva before returning to Paris. This resulted in latency of 38ms, which is quite close to that between Reading and Bologna.

Simulating the path from Reading to Bologna: GÉANT set up alternative routing to Paris based on source and destination addresses: direct route in yellow with a latency of 16.1 ms and a long route in red with a latency of 38.4 ms.

ECMWF's data centre houses ECMWF's new HPC. © ECMWF.


The tests allowed the best tuning parameters for the servers and the network equipment to be established, enabling a quick and efficient running of the final tests between Reading and Bologna, once the last leg of the network circuits went live in November 2020.

The test results gathered were really satisfactory and demonstrated the suitability of both the DTNs and the network.

The results suggested that 25Gbps for a single data flow and 90Gbps for multiple flows should be achievable between Reading and Bologna using the academic internet.

This compares very well to the baseline results of 30Gbps and 100Gbps respectively of the tests on direct routes. The next step forward is to see how the real-world applications would perform once the real transfers start to take place over the upcoming months.

“The collaboration between ECMWF and GÉANT on tuning the end hosts, ensuring good site connectivity and testing the end-to end network performance was excellent and I am really pleased to have been able to help them achieve the performance they require from the academic network.”

Richard Hughes-Jones, Senior Network Advisor, GÉANT



2 Exabytes* a year is already carried at high speed and low latency.

* (That’s 2 BILLION Gigabytes!)


Federating services and architecture plus eduroam, the worldwide WiFi roaming service.


Europe-wide procurement frameworks for tailored, market leading cloud offerings.


40+ NRENs, extensive partnerships, programmes, workshops, task forces and events.

The research GÉANT enables touches almost every aspect of our lives.
Not only that, but its networking technology is shaping the internet of tomorrow.

Find out more on the


Skip to content