Survivable Entanglement Path Provisioning for Quantum Networks Under Link Failures

Quantum networks establish end-to-end quantum communication by utilizing probabilistic quantum processes, including entanglement distribution between remote nodes and entanglement swapping at repeater nodes. While previous studies have aimed to maximize the number of entanglement connections under the probabilistic nature, physical link failures provide an additional challenge to ensuring consistent entanglement connections. To address this issue, a path provisioning model should be designed to maintain a high entanglement path success probability even in the presence of link failure. This paper proposes a survivable provisioning model to find link-disjoint entanglement paths in quantum networks, considering both link-level transmission success probabilities and node-level entanglement swapping success probabilities. The objective of the proposed model is to maximize the entanglement path success probability for survivability under link failure. We formulate this model as an integer linear programming problem. We prove that the decision version of the entanglement link-disjoint path finding problem in the proposed model is NP-complete. The numerical results indicate that the proposed model achieves up to 11.8% higher survivability than baseline algorithms. While the proposed model incurs longer computation time than the baselines, the required time is still within a feasible range; in our experiments, the maximum computation time is 4.1 seconds. Network operators perform path provisioning in advance of service initiation.