NetFridgeS: Enabling Dynamic Frequency Scaling on Network Switches through Carbon-Aware Routing#

Zhukun Wang; Noa Zilberman (University of Oxford)

• Why: Switches run at max pipeline clock 24/7 because nobody can afford a drop, while traffic is strongly periodic. Energy and carbon are becoming first-order DC fabric constraints (power delivery, PUE targets), and this is a concrete mechanism, not a positioning paper.
• What: Dynamic frequency scaling for high-performance switch pipelines, prototyped on FPGA across three pipeline architectures: sub-microsecond frequency switching, and an average energy saving of 77.74% at minimum throughput. Combined with carbon-aware routing over real topologies: up to 22.11% lower energy consumption and 27.76% lower carbon emissions vs. current deployments (from abstract only).
• How: Carbon-aware routing forecasts network utilization and adjusts pipeline frequency ahead of demand, so the pipeline slows down when and where traffic forecasts permit — solving the "must not drop packets" objection by tying frequency to predicted load rather than reacting after drops.
• Where applicable: Switch silicon design and fabric operations. The prototype is FPGA-based; merchant-silicon switches don't expose pipeline DVFS today, so near-term this is a signal to silicon vendors (and a design input) rather than a deployable feature. The forecasting-based approach is general.