Networking infrastructure vendor Cisco Systems, through its Outshift division, has released two software research prototypes targeting multi-node quantum network operations: the Cisco Quantum Network Controller and version 0.2.0 of its Network-Aware Quantum Compiler.
Building on the architecture of Cisco’s Universal Quantum Switch, the control plane establishes an Entanglement-as-a-Service (EaaS) abstraction layer. This framework enables compilers, application layer routines, and security protocols to request on-demand entanglement across multi-vendor QPU hardware without direct configuration of optical paths, physical device triggers, or timing parameters.
1. Cisco Quantum Network Controller Architecture
The Quantum Network Controller implements a software-defined control plane configured for the probabilistic and non-cloning characteristics of quantum states. Architectural components include:
| [ Cisco Quantum Network Controller Architecture ] | ||
|---|---|---|
| Software Layer | Technical Mechanisms & Abstraction | Operational & Network Functions |
| • Northbound API | • Entanglement-as-a-Service (EaaS) endpoints • Declarative intent interface | • Exposes rate, fidelity, and timing requests for compilers, sensing apps, and security protocols (Quantum Alert, Quantum Sync) |
| • Protocol Engine & Scheduler | • Stateful entanglement distribution, swapping & teleportation • Closed-loop telemetry & auto-retry logic | • Manages finite qubit coherence lifetimes, compensates for probabilistic Bell-pair generation failures, and reclaims idle network links |
| • Hardware Abstraction Layer (HAL) | • Southbound driver adapters • Standardized device category schemas | • Normalizes telemetry and control across multi-vendor sources, switches, detectors, and time taggers (including hardware from Qunnect and Swabian Instruments) |
Because quantum states cannot be inspected without state collapse, the Controller uses closed-loop statistical telemetry to monitor link health, executing predefined tuning or re-initialization when performance degrades. In a prior multi-node deployment across 17.6 kilometers of commercial telecom fiber in New York City, the software stack demonstrated polarization fidelity above 99% at room temperature using third-party hardware.
2. Network-Aware Quantum Compiler v0.2.0 & Distributed QEC
The Network-Aware Quantum Compiler v0.2.0 integrates circuit compilation, qubit partitioning, and distributed quantum error correction (dQEC) against physical network parameters. The compiler factors optical switch delay, fiber attenuation loss, communication qubit constraints, and inter-QPU surface code lattice surgery directly into the compilation workflow. Features include:
| [ Cisco Network-Aware Quantum Compiler v0.2.0 Key Features ] | ||
|---|---|---|
| Compiler Module | Algorithmic Implementation | Systemic Impact & Metrics |
| • Capacity-Constrained Partitioning | • Graph-cut strategies: Kernighan–Lin, METIS, and temporal window-based partitioning | • Minimizes inter-QPU remote gates by keeping heavily interacting qubits co-located within physical QPU boundaries |
| • Distributed QEC & Lattice Surgery | • Surface code patch layout & inter-QPU seam stabilizer measurement modeling | • Schedules repetitive inter-QPU Bell-pair generation required to execute lattice surgery across separate QPU modules |
| • Total Logical Error Rate (TLER) | • Unified analytical error model tracking local gates, network Bell-pair decay, memory idling, and magic state factories | • Provides architects with a single quantitative metric to evaluate network topology and code distance trade-offs prior to physical execution |
Review the full technical release on the Cisco Executive Platform here, examine architecture details on the Outshift Quantum Controller Blog here, and inspect the compiler SDK documentation on the Outshift Compiler Portal here.
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