Energy-minimised virtual topology design in IP over WDM backbone networks

As the Internet expands in terms of users and exchanged traffic, the energy consumption of the network is rapidly increasing and is becoming a very important issue. In backbone internet protocol (IP) over wavelength division multiplexing networks, it is possible to reduce the energy consumption by properly designing the IP topology and routing the traffic on it. The present study faces such a problem and proposes a novel heuristic algorithm derived from the `multi-hop grooming` strategy. The proposed algorithm is based on an innovative approach as it starts considering the solution given by the `single-hop grooming` strategy and then tries to eliminate unnecessary links by iteratively rerouting traffic flows. To achieve such an objective, a load-dependent cost function is used in the shortest path routing algorithm to compute link weights. Results obtained through simulations show that the proposed solution outperforms other algorithms proposed in the literature and performs close to the optimal solution. Moreover, besides showing a good performance in terms of energy efficiency, the proposed algorithm is also able to limit the maximum path length, saving a considerable amount of bandwidth and limiting the delay experienced by packets in the network.