Cisco and IBM have announced a joint research effort aimed at creating large-scale quantum networks that could eventually support a full “quantum internet.” Their long-term goal is to link many fault-tolerant quantum computers so they can work together on workloads involving hundreds of thousands of qubits. The companies hope to show an early proof-of-concept within the next five years, even though much of the required technology still needs to be invented.

As part of the partnership, the two vendors will explore both hardware and software needed to interconnect multiple quantum systems. Their initial experiment focuses on entangling qubits that sit inside different cryogenic setups. To make this possible, Cisco and IBM expect to develop new components such as microwave-to-optical transducers and a supporting software layer.

Cisco’s Vijoy Pandey said the challenge is not only building bigger quantum processors but also connecting them in a way that lets them function as one distributed system. IBM continues to advance its processor roadmap, while Cisco is working on the networking technologies that would allow these processors to scale out. Together, the companies plan to build the hardware links, distributed computing tools, and network control needed for coordinated quantum workloads.

IBM is also developing a Quantum Networking Unit, or QNU. This interface is meant to support research into microwave-based connections between quantum devices. IBM recently began working with the SQMS Center at Fermilab to entangle quantum computers located in separate cryogenic environments, connected through a microwave quantum link. The QNU concept could eventually support multiple quantum processors connected through a common network.

Cisco and IBM also want to push beyond short-range links. They aim to test how qubits might be transmitted across longer distances, such as between separate buildings or even across different data centers. This work includes studying optical photons, designing microwave-optical converters, and figuring out how these technologies could fit into a full quantum network.

Cisco is designing a software framework that can dynamically reconfigure network paths. The idea is to route entanglement to any pair of QNUs on demand, depending on what a quantum algorithm needs. The companies are also considering a bridge system made of new hardware and open-source software that could connect many IBM quantum processors inside a data center, then eventually across multiple facilities.

If successful, this approach could lead to large, distributed quantum computing clusters and, over time, a foundational layer for a future quantum internet. According to Cisco and IBM, these networks could begin to take shape toward the end of the 2030s