Cisco quantum controller schedules entanglement on demand

Cisco has unveiled a Quantum Network Controller, a research prototype that lets applications request entanglement from a quantum network without dealing with the hardware that produces it. The application says what it needs, and the network handles delivery.

Entanglement is a linked quantum state shared between distant points, and it is the resource quantum networks exist to distribute. Today, operators configure the equipment that creates it one device and one link at a time.

A scaling problem

Individual quantum processors still have fewer qubits than real workloads demand, so extra capacity has to come from connecting several machines. Those connections have so far been built point to point, which has kept quantum networks limited to a few nodes.

Anyone who wants a larger network for computing, security or sensing runs into a scheduling problem too big to handle manually. Someone has to decide who receives entanglement, at what quality, in what order and with what timing.

The numbers grow fast. Connecting a thousand nodes point to point would require close to 500,000 dedicated links. Cisco's Universal Quantum Switch, another research prototype announced earlier this year, is meant to replace those links with a single shared fabric. The new Controller is the software that schedules work across that fabric.

How it works

The Controller sits on top of a hardware abstraction layer and exposes one interface for each category of device: sources, switches, detectors and timing systems. Equipment from different vendors in the same category connects the same way.

An application specifies the endpoints, rate, fidelity and timing it requires. It does not need to know how the hardware delivers the result. Cisco calls this model Entanglement-as-a-Service.

Monitoring works differently than in classical networks. Reading a quantum state destroys the information it holds, so the Controller cannot inspect traffic the way a conventional monitoring tool would. Instead, it measures link quality statistically. When performance drifts, it applies predefined tuning, retries or reinitialization, and only alerts a human if that self-correction does not work. It keeps checking the link while an application is using it and takes the hardware back once the job is finished.

Field results

In February 2026, Cisco software coordinated multi-node entanglement distribution and swapping with partner hardware over 17.6 kilometers (about 11 miles) of deployed commercial telecom fiber in New York City. Polarization fidelity, a rough measure of how closely the delivered states matched the intended ones, was above 99 percent at room temperature. That test took place eight months before the Controller was announced.

The compiler comes first

The first native application for the Controller is an updated Network-Aware Quantum Compiler. It divides a quantum program across processors, calculates how much entanglement the network has to supply and between which nodes, and passes that request to the Controller.

The Compiler has no privileged access, which means a third-party compiler would use the same interface. Security and coordination applications named Quantum Alert and Quantum Sync are designed to request entanglement in the same way. On the hardware side, equipment from Brooklyn-based Qunnect and Swabian Instruments connects beneath the abstraction layer.

"Nobody has to keep a hand on every part anymore; we can now treat the quantum network as a system that delivers a service - whether it is to the application developer, to the operator, or to the hardware device vendor," wrote Vijoy Pandey, senior vice president of Outshift by Cisco.

Our Take

This is still a research prototype, and the tested setup was small. Even so, the approach is familiar to anyone who has watched classical networking mature. Cisco is pairing a shared switching fabric with a vendor-neutral control layer, which suggests quantum networks may be heading toward the same software-defined model.

For security teams, the defensive side of the quantum transition is still the pressing work. Projects like post-quantum signatures in OpenSSH show that effort is under way, while surveys keep finding that firms are unready for quantum threats.

It is worth watching whether Quantum Alert and Quantum Sync move beyond design. Another open question is whether other vendors adopt the Controller's interfaces, or whether competing standards emerge.