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Virgo: scale-out data center network for AI#

@Scale: Networking 2026 digest Program Core pick 25 August 2026

Abstract

Jeongkeun "JK" Lee (Google)

  • Why: Google splitting AI east-west traffic onto a purpose-built fabric — separate from Jupiter, which is retained for north-south — is a major architectural datapoint. Virgo will carry production ML traffic for Google Cloud's A5x bare-metal instances (NVIDIA Vera Rubin NVL72) and is a building block for next-gen TPUs, so its design choices will be exercised at frontier scale.
  • What: Virgo, a dedicated accelerator-to-accelerator east-west fabric optimized for massive horizontal scale, engineered for deterministic latency and maximum resilience to deliver high goodput for ML workloads. Design principles: resilience, observability, deployability, and multi-building scale. (from abstract only)
  • How: Optimized for the traffic shape of ML workloads (tightly coupled horizontal collectives) rather than general datacenter traffic; deterministic latency and resilience are stated design goals, but the mechanisms are not detailed in the abstract.
  • Where applicable: Google production and Google Cloud A5x instances; multi-building scale implies campus-scale cross-building connectivity. Google-specific build, but the split of "dedicated AI scale-out fabric beside the general-purpose fabric" mirrors choices at Meta and OpenAI and is an industry-direction signal.