Efficient ordering policy for secret key assignment in quantum key distribution-secured optical networks

Abstract

Quantum key distribution (QKD) is a promising solution to protect data transmission in optical networks against security breaches. Hence, several studies have paid attention on integration of QKD with the existing optical networks. Meanwhile, blocking is a challenging issue for QKD lightpath requests (QLRs) due to limited number of network resources (wavelengths and time-slots) in existing optical networks. In QKD-secured optical networks, the blocking increases with increase in the number of QLRs as well as with the modifications of secret keys for enhancing the security level of QLRs. Hence, the blocking affects the QLRs of different security levels, especially the QLRs of high and moderate security levels. Thus, the prioritization of QLRs based on the security level is essential for reducing the impact of blocking in such networks. In this paper, we propose a secret key assignment priority ordering policy (SKA-POP) for routing, wavelength and time-slot assignment (RWTA) to improve the success probability of QLRs. In the proposed SKA-POP, the resources during assignment and re-assignment are allocated based on the proposed priority criteria. The performance of the proposed SKA-POP is analyzed in terms of the success probability and the probability of secret key update failure (PSKUF). Simulations performed on two different network topologies, namely, NSFNET and UBN24, indicate that the proposed SKA-POP performs better than the non-priority based RWTA (NP-RWTA), priority order-based RWTA (POB-RWTA), partial-priority based RWTA (PP-RWTA), and a version of SKA-POP, i.e., SKA-POP with the longest route first (SKA-POP-LRF) schemes, when the number of QLRs (traffic load) increase in the network. © 2021 Elsevier Inc.