Fidelity-oriented routing in SDN-managed quantum networks

The paper examines an approach to increasing the stability and efficiency of hybrid quantum-classical networks by integrating the quantum fidelity metric into dynamic routing mechanisms of software-defined networks (SDN). The relevance of the study is determined by the necessity to account for specific characteristics of quantum channels, particularly stochastic degradation of quantum states under noise and external interference, which standard classical protocols ignore and known quantum routing algorithms insufficiently formalize. Despite existing fidelity-aware path selection methods, existing approaches predominantly rely on deterministic models or overlook dimensional consistency when aggregating heterogeneous metrics, limiting their suitability for dynamic adaptation in SDN-controlled architectures. The study aims to develop a theoretical-model approach to multi-criteria dynamic routing in SDN-managed hybrid quantum-classical networks, overcoming methodological limitations of known fidelity-oriented algorithms through parameter normalization, integration of a stochastic channel degradation model, and adaptation to centralized control. Methods of mathematical modeling, graph theory, and multi-criteria optimization were employed. A normalized route evaluation model is proposed, where delay, bandwidth, failure probability, and quantum fidelity are scaled to a single dimensionless range, ensuring physical correctness of the additive efficiency function. Algorithmic implementation is based on an SDN controller that dynamically adapts data transmission topology using predictive channel state estimation. Simulation results demonstrate a statistically significant increase in average integral routing efficiency and reduced indicator variability compared to classical approaches, confirmed by confidence intervals and the t-test. The obtained results have both theoretical and practical significance, serving as a foundation for designing future resilient telecommunication architectures.