Mariko Honda

We considered research and development aimed at improving the operability and scalability of large-scale QKD net-works (QKDNs) by introducing hierarchical control architecture. This paper focus on a distributed-control QKDN within such a hierarchical large scale QKDN and presents the design and implementation of a QKDN controller (QKDN-C) that selects appropriate key relay routes in response to control instructions from an orchestrator (QKDN-O). In particular, it describes a method for distributed key relay and routing table management, in which the routing tables of individual key managers (KMs) are dynamically updated on instructions from the QKDN-O. It also shows that, in a hierarchically structured QKDN, coordinated operation between the QKDN-O and distributed QKDNs enable key re-laying to be realized over optimal routes.