How to Build an NVIDIA Spectrum-X Ethernet Fabric for an AI Factory

This article provides a comprehensive guide to building an NVIDIA Spectrum-X Ethernet fabric for AI factories, emphasizing that it requires a coordinated transport system rather than a conventional Ethernet refresh. It covers key design principles such as separating compute, storage, and management networks; using routed leaf-spine topologies with adequate uplink capacity; aligning GPU network interfaces into predictable rails; treating RoCE as an end-to-end system with ECN, PFC, and congestion control; leveraging BGP and ECMP with adaptive routing; validating cabling and traffic balance; and monitoring via NetQ and telemetry. It also stresses the importance of designing for maintenance and failure domains before production deployment.