Switching Coordinator: An SDN Application for Flexible QKD-Networks

TL;DR

This paper presents a framework integrating SDN with QKD networks, enabling real-time monitoring and dynamic control to optimize cryptographic resource allocation and network resilience.

Contribution

It introduces a novel SDN application for QKD networks that provides real-time visibility and adaptive control for enhanced performance and security.

Findings

Effective real-time monitoring of QKD network metrics.

Dynamic network reconfiguration improves resilience.

Optimized resource allocation enhances performance.

Abstract

A monitor and control framework for quantum-key-distribution (QKD) networks equipped with switching capabilities was developed. On the one hand, this framework provides real-time visibility into operational metrics. Specifically, it extracts essential data, such as the switching capabilities of QKD modules, the number of keys stored in buffer queues of the QKD links, and the respective key generation and consumption rates along these links. On the other hand, this framework allows software-defined networking (SDN) applications to operate on the collected information and address the cryptographic needs of the network. The SDN applications dynamically adapt the configuration of the switched network to align with its changing demands, e.g.,~prioritizing key availability on critical paths, responding to link failures, or reallocating generation capacity to prevent bottlenecks. This contribution demonstrates that the combination of switched QKD, centralized control, and global optimization strategies enables efficient, policy-driven operation of QKD networks. The cryptographic resources are allocated to maximize performance and resilience while remaining aligned with the specific policies set by network administrators.