A Hybrid Fault-Tolerant Software-Defined Networking Architecture for Reliable Operation of Critical Infrastructure Networks

Abstract

Critical infrastructure networks such as power grids, industrial control systems, and transportation platforms require highly reliable and resilient communication frameworks to ensure uninterrupted operation. Software-Defined Networking (SDN) has emerged as a promising paradigm for managing such networks due to its centralized control, programmability, and global network visibility. However, the separation of control and data planes in SDN introduces reliability challenges, particularly the risk of controller failures, control-plane bottlenecks, and delayed recovery from network faults, which are unacceptable in mission-critical environments. This study proposes a fault-tolerant SDN architecture designed to enhance the reliability and operational continuity of critical infrastructure networks. The architecture integrates a distributed controller framework with state replication, proactive failure detection, and fast data-plane recovery mechanisms to mitigate the impact of controller, link, and switch failures. A hybrid recovery strategy is adopted, combining local fast rerouting at the data plane with coordinated control-plane failover to minimize service disruption and recovery latency. The proposed architecture is evaluated through simulation under multiple fault scenarios representative of critical infrastructure environments. Performance metrics such as recovery time, packet loss, throughput, controller failover latency, and network availability are analysed and compared with conventional single-controller SDN architectures. Results demonstrate significant improvements in fault recovery speed, service availability, and resilience under both control-plane and data-plane failures. The findings highlight the potential of fault-tolerant SDN architectures as a viable solution for enhancing the reliability of critical infrastructure networks.