Quality of Service Evaluation over a 496 km Quantum Key Distribution Network

Quantum key distribution (QKD) technology has remarkably developed, and some countries are in the stage of preparing quantum cryptography communication services beyond the PoC. To ensure the stability of QKD network operation telecommunication service providers and engineers need to verify the quality of service (QoS). To do this, we built a quantum cryptography communication network testbed for 496km distance with nine trusted relay nodes in Korea, to evaluate the QoS of the quantum cryptography communication network. Also, we apply four QoS parameter values defined which are quantum key response delay, quantum key response delay variation, quantum key loss rate, and availability. By measuring each parameter in a real quantum cryptography communication network, we show that this method is valid to evaluate QoS, and it is expected to contribute to the realization of quantum cryptography communication services.