Closing the gap among IP and per-flow green routing solutions. The tunneling approach

This paper proposes a novel energy-aware adaptive routing solution to face the energy consumption problem in IP networks, exploiting the IP over IP tunneling technique. The problem of minimizing the number of used links by configuring a set of tunnels, referred to as energy minimized tunneling (EMT), is modeled as an integer linear programming problem. The general EMT problem is then slightly modified by adding a set of constraints to make it more applicable to real networks scenario. With respect to previously proposed solutions, the EMT formulation exploits IP tunneling to change traffic routing assuring three main features: 1) no modifications to both data and control planes of current IP routers, so representing a feasible short-term solution for actual IP networks; 2) no need of IP routing protocols convergence to modify the routing paths, so avoiding routing instabilities; and 3) performance comparable with flow-based solutions requiring the deployment of a connection-oriented protocol. We propose a practical solution, called Virtual Interface oN Off (VINO), that exploits the tunnel aggregation mechanism in order to reduce EMT operational complexity. VINO works in two steps and it is based on the preconfiguration of a limited set of (virtual) tunnel interfaces along with a set of static routes on IP routers; thus, these virtual interfaces are dynamically activated and deactivated according to traffic variations. The performance analysis carried out demonstrates that VINO is able to outperform IP green routing solutions proposed in the literature, in terms of energy efficiency.