Green Networks: Improving the Energy Efficiency of ICT

Prof. Ken Christensen
Department of Computer Science and Engineering, University of South Florida, Tampa, Florida, USA

25 hours, 6 credits

May 24 - May 28, 2010

Area della Ricerca di Pisa, National Research Council, via G. Moruzzi 1, Pisa, room 7, entrance 3

Contacts: Dott. Marco Conti

This activity is part of the Pisa International School on the Next Generation Internet.



ICT is a direct contributor to more than 2% of global CO2 emissions, and this is expected to double in the near future. Networks are a large part of the overall energy consumption of ICT. Energy consumption of networks is both direct (from network links and equipment) and induced (from hosts forced to remain in a higher power state to maintain connectivity). In this series of lessons, we will cover the energy consumption of ICT, explore current research in reducing both direct and induced energy consumption of networks, briefly explore future directions where networks can enable the reduction of energy consumption in other sectors of the economy, and review ongoing green network standards, initiatives, and products. It will be seen that green networks offer the researcher a range of modeling and systems problems. The primary focus of this course will be on the Internet and the network equipment and hosts that connect to it where large savings can be achieved (as such, energy issues specific to cellular networks and wireless ad hoc and sensor networks are not covered).


  • Introduction and motivation (2 hours)
  • Energy consumption of ICT and networks (data centers, core, and edge)
  • Goal of energy-proportional computing
  • Overview of dynamic power management (3 hours)
  • Time scales, mechanisms, and policies
  • Prediction of idle periods
  • Reducing direct energy consumption (8 hours)
  • Energy Efficient Ethernet (including modeling)
  • Power management of switches and routers
  • Traffic shaping
  • Reducing induced energy consumption (6 hours)
  • Proxying to enable host sleeping
  • Green P2P and nano data centers
  • Indirect energy savings from networks (2 hours)
  • Smart grid
  • Major initiatives and commercial products (2 hours)
  • EPA Energy Star
  • Climate Savers Computing and others
  • Verdiem Surveyor, Cisco Energywise, Avaya Go Green, and others
  • Summary and future directions (2 hours)