In Routing Protocol for Low-Power and Lossy Networks (RPL), a node with relatively high traffic compared to its neighbors is called a hotspot node. Any node in RPL can be targeted for attacks such as packet drops and misleading packets, but hotspot nodes are more prone to these attacks because of their traffic nature. These attacks will reduce the efficiency of the network by increasing the packet loss and end-to-end delay. In this paper we get the impression from game theory and propose a strategic defensive mechanism (SDM) for the attacks on hotspot nodes. The SDM dictates the Intrusion Detection and Prevention System (IDPS) to take Prevent Before Attack (PBA) and Defense After Attack (DAA) in a strategic manner. Our simulation results show that PBA strategy has better working condition when the number of attacks on a network is relatively high. The results also reveal that an energy-efficient encryption algorithm is required for the further improvement of this scheme.
