Community News Community Programme Magazine Network

Networks and data centres: time to talk about energy efficiency

Words: Gabriel Verdejo Álvarez (/rdlab); Ivana Golub (PSNC); Maria Isabel Gandìa (CSUC); Sebastian Neuner (Belwü); Silvia Fiore and Tony Barber (GÉANT); and Simon Leinen (SWITCH).

Energy efficiency is a hot topic these days and rightfully so, due to both environmental reasons and increasing electricity prices. This is why it was the main topic of the 17th meeting of the Special Interest Group on Network Operation Centres (SIG-NOC) which took place in November 2022 in Paris hosted by the French NREN, RENATER.

Even though awareness of a strong dependency on external energy sources was known and considered before, recent global events caused high increases of energy costs that, together with a growing eco- and green-consciousness, motivated network operators to explore deeper their current modus operandi as well as existing solutions and opportunities to reduce carbon footprints.

The change is visible in several areas, and equipment vendors are providing Management Information Bases (MIBs) with power consumption data which enables network operators to monitor it on a regular basis. Using this opportunity, network operators are taking further steps by analysing existing usage and measuring energy usage per port. They are also considering alternative solutions, such as optimisation of system topology and configuration, lowering network over-provisioning for power savings, interaction with energy network, and also considering lower consumption equipment during a network equipment procurement process.

For these reasons, many NRENs in Europe and beyond are actively working on using renewable energy sources in two domains – electricity and waste heat, and being able to offer generated energy to other organisations.

PSNC logoIn this area, PSNC has evolved from fostering energy efficiency to using sustainable energy systems, through activities and collaborations with other institutions and utilities. For instance, re-using heat generated by the data centre for the office and Campus buildings and working to offer the surplus to the District Heating operator during warmer months. PSNC is also using a photovoltaic installation close to facilities with laboratories, to maximise the use of self-consumption, and locating network nodes in containers that use renewable energy.

Tony Barber, Head of the GÉANT Operations Centre, presented on how GÉANT has included energy efficiency ratings into recent network hardware procurements and how it was able to measure or closely estimate current energy usage. The challenges in measuring exact power usage and the hardware required to do this were discussed along with the differences in AC vs DC usage and why the decision may not be as clear cut as it used to be. By taking a close interest in energy utilisation, GÉANT was able to show how it has doubled the network capacity for a similar power draw achieving an effective 60% net reduction in energy usage. Reducing the carbon footprint and promoting environmental sustainability is a top priority in GÉANT’s corporate responsibility program.

Unexpected consequences

Switch logo newAnother presenter was Simon Leinen, Network Engineer at SWITCH. He shared that halfway through 2022, Swiss authorities pointed out the risk of a nationwide shortage of electrical power for the coming winter(s). Countermeasures included planned four-hour regional outages. Rightfully, many in the local community were concerned how the SWITCHlan backbone could survive such outages! SWITCH’s equipment is mostly hosted at universities, and for decades they have been relying on the power provided to them. After running a survey, a few “soft spots” were identified, where unlucky combinations of regional outages could “partition” the backbone—a situation to avoid. Some of those were addressed by individual member institutions improving backup power; for others, SWITCH procured, tested, and deployed their own battery-based backup solutions.

According to Simon “This all was a significant amount of (unplanned) work that sometimes pushed us out of our comfort zone. On the other hand, our community appreciated the effort and was eager to help.

Intelligence design to reduce power

Sebastian Neuner from Belwü, the data network of the scientific institutions of the German state of Baden-Wuerttemberg, also presented their energy-efficiency initiatives at the meeting in Paris. With energy prices going up, Sebastian’s team was tasked with reviewing their energy footprint and quickly noticed that they were making a lot of assumptions that were not tested or documented, nor were any scientific data available for the current hardware.

As a general rule of thumb, you always need more: space, power, battery run-time, cooling,” says Sebastian. “With more efficient gear and a more efficient design, you can do more using the same resources.

His team decided to run their own lab tests with some brand new 32x 100GE router line-cards that just had arrived. They found that the actual traffic passing through the line-cards could theoretically be up to 23% of the power consumption. This is at maximum packets per second, so in practice the traffic would only make up a single digit percentage of the power. A whopping 70% of energy goes to the line-card itself, without traffic or configured services running, even with the interfaces disabled.

Disabling links between routers during times with low traffic volumes could save between 7% and 10% at the cost of losing redundancy and maybe sending traffic on longer paths. Having a network design where additional capacity is collected on a common line-card that can be powered down while traffic levels are low could save a lot of energy. Switching line-cards on and off is currently very slow and inconvenient, but there are situations like power outages, where this sort of load shedding could be helpful.

Finally, Gabriel Verdejo Álvarez from the Research and Development Lab (/rdlab) from Universitat Politècnica de Catalunya (UPC) shared his team’s institutional experience at the meeting in Paris. He highlighted that, with the increasing energy demands from HPC and cloud services, it is important to focus on energy efficiency rather than simply saving on electricity. According to the Times Higher Education (THE) Impact Rankings, UPC ranked 38th in the achievement of SDG 13 (Climate Action), climbing 33 positions from the previous edition! This is due particularly thanks to the vast educational resources on the topic, including the UPC 2030 Sustainability Campus and the IT efficiency modules that is part of the Engineering studies.

As the attendees of the SIG-NOC meeting could see, increasing costs and the green consciousness have pushed several organisations in the research and education community to investigate and work on energy-related initiatives from different angles. On the one hand, the risk of nationwide power outages and restrictions makes it mandatory to have all the right backup mechanisms in place. On the other hand, optimising energy consumption for the computing and networking areas is becoming more relevant every day. The strategy of the organisations needs to be aligned with reduction of the carbon footprint, as investments may be needed to achieve the final goals and the architecture, the services and the physical devices are involved. From using renewable power sources or re-using the heat generated by the equipment to switching down connections while they are not in use, all the options are open and can help.

Research and education organisations can follow the path to energy efficiency from the ideas and the discussions held during the meeting. For instance: having a set of recommendations for tenders and procurements of network equipment and services to invest in energy-efficient systems, collaborating with other organisations to re-use heat generated by the datacentres, performing measurable actions that have a real impact in power consumption. And, of course, being ready for unplanned network outages!

If you want to learn more about the topic, you can visit the meeting wiki page and download all the presentations.

GÉANT CONNECT Magazine - CONNECT 44. How do GÉANT and the NRENs support Open ScienceThis article is featured on CONNECT 44, the latest issue of the GÉANT CONNECT Magazine!

Read or download the full magazine here



Skip to content