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In software-defined networking (SDN), the control plane is separated from the switching plane (i.e., data plane). The logically centralized control plane is implemented by physically distributing several controllers throughout the network for scalability and resilience. The problem of finding the number and location of the SDN controllers is known as the controller placement problem (CPP). In this paper, we consider the following robust CPP problem variant. For a given maximum switch-controller (SC) delay and a given maximum controller-controller (CC) delay in the regular state, we aim to find a CPP solution that maximizes the network robustness for a given number of malicious node attacks. First, we guarantee that if all but one controller nodes are shutdown, there is still a switching path from any switch to the surviving controller. We propose an ILP based method aiming to enumerate all such solutions. Then, for …