The Project

Duration: October 2010 – December 2013

Funding scheme: Collaborative Project

Total cost: € 9.96 m

EC Contribution: € 6.16 m

Contract number: INFSO-ICT-258454

The Partners
ECOnet social

Green Technologies for Network Device Data Plane

The starting basis for ECONET will be a heterogeneous set of energy-aware hardware technologies available on the market and generally employed to build current network equipment (e.g. FPGA, ASICs, network/packet processors, multi-core COTS processors and NICs). The project will explore how to effectively exploit and adapt their power management features and capabilities in device architectures in order to meet network operational constraints.
Power consumption
Fig 1: Estimate of power consumption sources in a generic platform of IP router.

To this end, this research axis will focus on the data-plane of network equipment, since this usually include the most energy starving HW elements, with a weight equal to 54% vs. 11% for the control plane and 35% for power and heat management (Fig. 1).

Starting from this basis, the ECONET project will introduce, explore and develop two main kind of network-specific energy-saving capabilities, i.e. dynamic power scaling and smart standby, respectively (Fig. 2).

The first type of mechanism will allow network devices tuning dynamically the trade-off between energy profile and processing capacity of internal processing blocks/engines, while meeting the actual traffic load and QoS constraints. This will directly impact:
  • The design of novel traffic handling policies and queuing/shaping disciplines, which will be able to effectively exploit active/idle HW transitions;
  • The development of green extensions for L2 protocols.

In detail, focusing on transport/core devices, modular systems are usually built with embedded switching capability that is tuned for maximal system capacity. When the system is under partial load, then parts of the system switching logic can be powered off or throttled in order to reduce overall system power consumption without an impact on the overall performance.

For example, MLX modular switches system architecture relies on line cards and spine cards. The spine cards provide the switching capability between all the line cards. The spine cards power can be adjusted when the system is under partial load by either throttling speed/power of the spine cards or by powering on/off complete spine cards according to the load. With these mechanisms the overall system power can be adjusted. This can be controlled using interfaces, defined by the ECONET consortium, to overall management of power of each system and of the overall network. Further performance/power trade-offs can be also made available through the abstraction layer.
Green enhancements
Fig 2: Green enhancements and capabilities at the device data-plane.

As far as the link protocols are concerned, among the other efforts in this field, the ECONET consortium will study green extensions for lossless Ethernet (i.e., 802.1Qau, 802.1Qaz and 802.1Qbb). The properties of such protocols can contribute to power reduction/saving across the network by maintaining smaller buffers and avoiding energy investment on retransmissions. Part of the ECONET project can include research of applying lossless techniques to the power saving schemes in the ECONET network equipment.

The second typology of mechanisms will allow putting currently unused parts of a network devices (such as redundant network interfaces, unused network terminations, etc.) into very low energy consumption modes, where only some basic functionalities are performed (e.g. heart-beating message reply).
The development of such network-specific low-energy modes is a fundamental key factor for disruptively reducing the carbon-footprint in different network scenarios, since it will allow switching some portions of the network (links, part of network devices, entire network devices) to a sleep mode in a smart and effective way.
The key advantage of such solution with respect to a simple switching-off consists in reduced recovery times as well as in the possibility of avoiding useless signalling storms of routing protocols at each active/sleep transition of links or nodes.

In this respect, on the network access side, today most operators do not use low power mode available on ADSL systems as entering and leaving this mode risks de-synchronizating other lines in the bundle. The resulting re-training of the lines needs tens of seconds, which is not accepted by users.
Although optical technologies will not have these problems, millions of DSL lines will stay in place or many years. Also with the mixed opto-electrical technologies like FTTC the last 100 meters remain copper lines operated with VDSL. This technology offers more bandwidth at the expense of more power. It is even more important to save power with VDSL.

Also in VDSL the crosstalk is higher, especially for the high frequencies. A special effort of the ECONET project will be devoted to these aspects, and contributions will be focused on DSM mechanisms for VDSL systems (DSLAMs and home gateways). For example, LQDE will bring in one or more prototype systems with at least 16 DSL lines, which support echo cancellation in up- and downstream direction.

The idea exists that in a fully equilibrated DSM bundle there is virtually no crosstalk. Hence a line of the bundle could be switched off and on again without disturbing the other lines.

Private area
  • GAL definitely approved as ETSI standard
  • Memberhip voting phase and publication of the GAL standardization
  • ETSI EE Technical Board (TB) approval for GAL standardization
  • ECOnet contributed with the official code of conduct on energy consumption of broadband equipment version 5.0