How fast can it wake up? Putting Link Sleeping into Practice

The Internet consumes a few percents of the world-wide energy today, and the trend is rapidly increasing. This observation was made already two decades ago [1]. It triggered researchers to explore ways to reduce the energy consumed by networks. The basic principle is well-understood: it’s called duty-cycling. That is, turn off parts of a system you don’t need whenever possible. This is how phones and other connected devices manage to run through the day with small batteries.

The theory of duty-cycling in networks was explored in [2] and other following works. But there is a practical caveat: duty-cycling requires turning off parts quickly and efficiently. The authors of [2] assumed a router’s linecard could be switched on or off in 1 $\mu s$; today, it takes in the order of minutes [3]. In addition, traditional routing protocols are not designed to handle parts of the networking shutting off regularly; they treat each link down as a failure and consequently trigger expensive routing updates. Researchers adaptations such as GRiDA [4] or GOSPF [5]; however, those protocols are complex because they try to “tape a broken arm.” Rather than fixing the existing protocols, we need a routing protocol design that take node and link duty-cycling as a first-class citizen.

This thesis aims to address those problems. Specifically,

  • Rethink the hardware design of network linecards to shorten its wake-up time; that is, the transition from a low-power mode to an active one. How low-power can we get? How fast can it wake up?
  • Rethink the routing protocols starting from the hypothesis that links, linecards, and possibly entire nodes will regularly turned off. How and how much energy can we save while maintaining routing performance.


  1. Gupta M, Singh S. Greening of the internet.
    SIGCOMM ‘03
  2. Nedevschi S, Popa L, Iannaccone G, Ratnasamy S, Wetherall D. Reducing Network Energy Consumption via Sleeping and Rate-Adaptation.
    NSDI ‘08
  3. Pan T, Zhang T, Shi J, Li Y, Jin L, Li F, et al. Towards Zero-Time Wakeup of Line Cards in Power-Aware Routers.
    ToN ‘16
  4. Bianzino AP, Chiaraviglio L, Mellia M, Rougier JL. GRiDA: GReen Distributed Algorithm for energy-efficient IP backbone networks.
    Computer Networks ‘12
  5. D’Arienzo M, Romano SP. GOSPF: An energy efficient implementation of the OSPF routing protocol.
    Journal of Network and Computer Applications ‘16