MadQCI: a heterogeneous and scalable SDN QKD network deployed in production facilities

TL;DR

MadQCI presents a flexible, scalable, and real-world deployable heterogeneous SDN QKD network that integrates multiple technologies and supports commercial telecommunications infrastructure.

Contribution

This work introduces a disaggregated, adaptable QKD network architecture deployed in production facilities, enabling real-world scalability and integration with existing telecom systems.

Findings

Successful deployment of multiple QKD systems from various manufacturers

Demonstrated network flexibility with different link technologies

Continuous operation over nearly three years in a real-world environment

Abstract

Current quantum key distribution (QKD) networks focus almost exclusively on transporting secret keys with the highest possible rate. Consequently, they are built as mostly fixed, ad hoc, logically, and physically isolated infrastructures designed to avoid any penalty to the quantum channel. This architecture is neither scalable nor cost-effective and future, real-world deployments will differ considerably. The structure of the MadQCI QKD network presented here is based on disaggregated components and modern paradigms especially designed for flexibility, upgradability, and facilitating the integration of QKD in the security and telecommunications-networks ecosystem. These underlying ideas have been tested by deploying many QKD systems from several manufacturers in a real-world, multi-tenant telecommunications network, installed in production facilities and sharing the infrastructure with commercial traffic. Different technologies have been used in different links to address the variety of situations and needs that arise in real networks, exploring a wide range of possibilities. Finally, a set of realistic use cases have been implemented to demonstrate the validity and performance of the network. The testing took place during a period close to three years, where most of the nodes were continuously active.