Minimize Penalty Fees During Reconfiguration of a Set of Light-Tree Pairs in an All-Optical WDM Network

Multicast connections are efficient for applications such as telemedicine, distributed computing, and distance learning in an all-optical WDM network. To re-optimize the use of network resources such as wavelength channels in the all-optical WDM network, the network operator uses the reconfiguration operation, which affects certain multicast connections. Note that during reconfiguration, a pair of light-trees contributes to the identification of each multicast connection. A light-tree is a path used to transmit an optical flow of a multicast connection. However, the interruption of the flow during reconfiguration of a pair of light-trees may result in the operator having to pay a penalty fee. Thus, the problem studied here is to reconfigure a set of light-trees pairs while minimizing penalty fees. Existing methods focus on reconfiguration that aims to minimize flow interruptions. However, minimizing flow interruptions does not induce the minimum total penalty fees because the penalty fees due to flow interruptions are not always the same for all multicast connections. Therefore, we propose a method that considers the fact that the penalty fees are not the same for all multicast connections to minimize the penalty fees during reconfiguration. The experimental results confirmed the effectiveness of the proposed method.