After the big Internet growing of the past decade, in the current decade a considerable effort is spent to reduce the Internet energy consumption. Actual Internet topologies have space to power off some links and devices in order to reduce energy consumed in off-peak periods still guaranteeing connectivity among terminals. In this paper we propose a methodology to identify less used links in the network in order to have the capability to switch off these network interfaces for energy saving purposes. We describe four different algorithms able to identify this set of links and we show the tradeoff between complexity, and the consequent execution time, and efficiency in powering off a great number of links. We find that, by using our solutions, it is possible to switch off a big percentage of links still keeping the network load under suitable thresholds and still guaranteeing topological characteristics of the resulting network topology.