PALS: Saving Network Power With Low Overhead to ISPs and Applications

Power saving in the network infrastructure has received great attention in recent years. Power-aware traffic management is proposed in many works, in which a subset of routers/links are preferentially used to carry traffic while other links are activated only when traffic load is high. However, it remains challenging how to minimize the overhead to both ISPs and applications, which is important to the successful deployment of power-aware traffic management in a real network. This paper presents PALS, a new Power-Aware Link State routing based traffic management protocol. Compared with previous solutions, PALS remarkably reduces the overheads to ISPs and applications by the following innovations. First, PALS minimizes the forwarding table expansion due to dynamic power-aware routing, by using destination based routing instead of pairwise routing (e.g., MPLS). Second, PALS limits packet reordering for applications, by never splitting traffic between an IE (ingress-egress) router pair to multiple paths. Third, PALS significantly reduces the computation complexity of the power-aware routing algorithm, by running a simple path selection algorithm at each ingress router with the knowledge of local traffic information as well as global link utilization, which are much easier to obtain than global traffic matrix required by the state-of-the-art solutions (e.g., Zhang , IEEE ICNP 2010). Extensive simulations and testbed experiments show that, although bearing the simplicities to minimize the overhead, PALS saves satisfactory network power, with quick response to traffic variance and negligible impact on the packet delivery performance for applications.