To switch on or off: A simple case study on energy efficiency in IP-over-WDM networks

In this paper, we present a simple case study on energy efficiency in IP-over-WDM networks with dynamic circuit capability and compare two different load adaptive schemes, referred to as switch-on and switch-off. While the switch-off technique was already proposed for energy conservation, the switch-on approach is a new paradigm which is based purely on one-time implementations of dynamic circuit capability. Our results show that both approaches can significantly reduce the power consumption and decrease the necessary totally installed capacity, but unlike the switch-off scheme, the switch-on scheme does not affect the path redundancy in the network. Furthermore, switch-on can reduce the number of routing reconfigurations required in the network. While this seems ideal, our results also show that the switch-on scheme uses a large number of small capacity interfaces which may not be suitable from a network planning perspective as it might require frequent capacity upgrades, which alone is an interesting avenue for future research.