1. An energy efficiency method in a discovery node, comprising: measuring a level of utilization of a network link supported by said discovery node; controlling, via an energy efficiency control policy operating in said discovery node, an operating state of components in said discovery node that support said network link, said energy efficiency control policy receiving as a first input said measured level of utilization of said network link; transmitting, from said discover node, discovery traffic to each of a plurality of network nodes; generating a measure of current network performance for each of said plurality of network nodes based on messages received from said plurality of network nodes in response to said transmitted discovery traffic; and adjusting an effect of said energy efficiency control policy on said components in said discovery node based on a second input based on said generated measure of current network performance for each of said plurality of network nodes.