Physical Network Design at Scale + 3 min Q&A#

Richard Cziva (Meta), Brandon Premo (Meta)

• Why: Physical network design — placing thousands of devices and planning millions of fibers under failure-domain constraints — has been stubbornly manual, and AI demand makes that manual process the bottleneck. Loom is a concrete, deployed system that compressed end-to-end design from months to hours. Squarely in the PM's physical-datacenter plus automation interests.
• What: Loom, Meta's system for automating the end-to-end physical network design pipeline, orchestrating two components: Planogram, which places network devices across the physical floorplan subject to dimensional and failure-domain constraints, and a fiber design component that generates end-to-end fiber connectivity across the variety of connectivity patterns driven by physical constraints. Together they cut design time from months to hours and produce more complex, more efficient designs with fewer resources. (from abstract only)
• How: Constraint-based device placement plus automated fiber connectivity generation, orchestrated as a pipeline — cleanly decomposing "where devices go" from "how everything gets cabled."
• Where applicable: Built against Meta's floorplans, fabric families, and failure-domain rules — the constraints are Meta-specific — but the decomposition (constrained placement plus automated fiber path design) transfers to any large operator and is a strong candidate pattern for vendor tooling roadmaps.