Joint Scheduling and Routing for QoS Guaranteed Packet Transmission in Energy Efficient Reconfigurable WDM Mesh Networks

The explosion of Internet traffic calls for quality of service (QoS)-guaranteed packet transmission in wavelength division multiplexing (WDM) networks with high energy and bandwidth efficiency. Conventional routing and wavelength assignment (RWA) algorithms focus on circuit switching, which does not well meet this requirement due to the bursty nature of IP traffic. Based on a novel traffic matrix decomposition technique, we study the joint design of traffic scheduling and routing in a reconfigurable WDM optical network to improve energy and bandwidth efficiency. Specifically, every node in the network is equipped with a set of parallel tunable lasers, each with a reconfiguration overhead. A dynamic matrix is adopted to model the traffic among the nodes and is decomposed into a set of transmission configurations (i.e., traffic scheduling). The configurations are then fulfilled by tuning the parallel lasers and routing the scheduled traffic under the topology constraint, to achieve loss-free packet transmissions with bounded delay (i.e., QoS guarantee). We reveal that a tradeoff exists between the packet delay and the required number of tunable lasers. The latter is then minimized under a given packet delay to save energy. As far as we know, this is the first work to adopt traffic matrix decomposition in WDM networks to save energy. The proposed framework is validated by extensive simulation studies.