Digital Agenda for Europe
A Europe 2020 Initiative

Energy-efficient networks: green by design

The ECONET project demonstrated technologies that slash the energy used by telecommunications networks by more than half; the interface that brings the technologies together has already been approved as a European standard.
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It is ironic that while information and communication technologies (ICTs) are frequently used to reduce energy consumption – particularly in manufacturing – little attention has been paid to energy consumption within the sector itself.

With telecommunications and internet use climbing rapidly, the sector – once hailed as the answer to many environmental concerns – is now itself a massive consumer of energy. In 2010, Europe’s telecoms operators used the equivalent of 21.4 TWh. This figure is expected to rise to 35.8 TWh in 2020 if nothing changes.

With the Internet of Things expected to increase usage yet further, it is important that energy efficiency becomes pivotal within the network infrastructure, to the extent that it is considered at the design stage. This will not only benefit the environment but also cut costs for operators.

The ECONET project has laid the ground for this to happen. The team had to start from scratch, explains ECONET coordinator Professor Raffaele Bolla of the Telecommunication Networks and Telematics Lab at the University of Genoa. The three-year project developed a coordinated set of approaches to dynamically adapt a network’s capacity and resources to traffic loads and requirements.

The team did this by designing a more efficient power management interface that can be adapted to the type of equipment and technologies used by various network operators. The interface was approved as a standard by the European Telecommunications Standards Institute (ETSI) in March this year. “It’s very rare to find a project able to standardise its results during the project itself,” says Bolla proudly.

Another key achievement was demonstrating that using all of the techniques developed within the project together can reduce energy consumption for telecommunications by more than 50% – and actually up to 70 or 80% depending on the device used and network set-up.

“It was not so clear at the beginning of the project that it really would be possible to reduce energy consumption by 50% – there is often a difference between theory and practice!” says Bolla. But the team has shown that it is possible, without question, to shrink a network’s environmental impact.

ECONET’s impressive results came out of research in three key areas:

  • green technologies for the network device data plane (standby and dynamic power saving);
  • green strategies for the control plane;
  • the green abstraction layer.

“It’s very rare to find a project able to standardise its results during the project itself.”

Powering down

Smart standby and dynamic power-saving techniques can lead to big reductions in energy use. The first would allow parts of the network to switch to a very low energy consumption mode when unused so that only very basic functions are performed.

Dynamic power saving allows network devices to make a trade-off in real time between energy needs and processing capacity while meeting traffic and quality of service requirements. This would clear the way for operators to set novel traffic-handling policies and queuing disciplines able to exploit active and idle hardware transitions.

A number of heterogeneous, energy-aware hardware technologies – such as switches, routers and home-gateways – are already available on the market. The ECONET team looked into how their power management features could be exploited in device architectures while respecting network operational constraints.

For example, a device usually has an embedded switching capability that is set at maximum system capacity. When the system is only dealing with a partial load, parts of the switching logic can be powered off to reduce power consumption without affecting overall performance.

Adapting to traffic

Using the findings from the network device data plane research, the team turned to the design of local and distributed frameworks for energy-efficient and flexible network operation. Network administration and management was also a key focus. The goal was dynamic, scalable, ad-hoc and optimised resource allocation that balances the trade-offs between energy consumption and network performance, as well as differentiated performance, fault-tolerance and robustness levels.

A non-negligible part of the work focused on cooling systems, which account for around 35% of a network’s energy use. The team used data gleaned from monitoring heat dissipation in network equipment to develop ways of reprogramming cooling systems to save energy.

Next steps

ECONET next brought the control plane and data plane together in what the team calls its ‘third axis’ – the Green Abstraction Layer – to develop the now-standardised general purpose interface for controlling novel green capabilities and functionalities. The interface hides the interaction between these capabilities and hardware technologies, on the one hand, and energy-aware and control and monitoring frameworks, on the other.

Already recognised by ETSI as standard ES 203-237, the interface will now be presented by the project team to another body – the International Telecommunication Union – Telecommunication standardisation sector (ITU-T) – for guidance on additional developments.

The challenge is then to raise awareness of the technologies and techniques developed within the project to encourage take-up. Acceptance as a standard should help, and the team is planning a new project to both promote ECONET’s results and the idea that energy efficiency should be at the heart of research in this field.

Bolla’s target audience is quite extensive, ranging from the research and development community to customers such as telecoms providers and private users. Industry and politicians are also important – in addition to the long-term energy and cost savings, they need to understand the short-term advantages of switching to the new technologies.

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