An On-demand Routing Scheme with QoS Provisioning for QKD Networks

As an emerging technology, Quantum Key Distribution (QKD) can provide information-theoretically secure keys for cryptographic purposes and it attracts worldwide attention. To extend its service capabilities from point-to-point communication to arbitrary remote communication parties, large-scale QKD network construction is underway. However, the dynamic and limited available resources of QKD networks remain a major obstacle to routing design. Numerous studies aim at designing routing schemes to maximize the overall network performance. While these routing schemes efficiently support end-to-end key relaying, their effectiveness diminishes when addressing diverse Quality of Service (QoS) requirements. In this paper, we propose an on-demand routing scheme with QoS provisioning to enhance end-to-end key relaying rates. Our scheme operates in two phases: an on-demand resource probing phase to dynamically update global network resource information and a routing decision phase that leverages a maximum flow model to optimize key relaying while satisfying rate-demand constraints. Simulation results on the SimQN platform demonstrate that the proposed scheme significantly improves end-to-end key relaying through-put and delay, providing effective QoS support for rate-demand QKD applications.