Dragonfly worst-case diameter on minimal routes, in router hops. Separately, Google says its dragonfly-inspired TPU 8i Boardfly cuts a 1,024-chip pod from 16 chip-to-chip hops (8x8x16 torus) to 7 (announced April 2026).

Name: Dragonfly worst-case diameter on minimal routes, in router hops. Separately, Google says its dragonfly-inspired TPU 8i Boardfly cuts a 1,024-chip pod from 16 chip-to-chip hops (8x8x16 torus) to 7 (an…
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≤3 hopsobserved

Value kind	observed — Reported measurements, counts, and specifications keep the precision and scope stated by their source; an exact specification is not treated as a range.
Caveat	The Boardfly hop figure is Google's own (vendor claim) for a product announced but not yet generally available. Boardfly counts chip-to-chip hops, not switch hops.
As of	2026-04
Source	Google Cloud, TPU 8t and TPU 8i technical deep dive (2026-04-22)
Review	checking…review by 2027-01-31 · standard cadence
Recorded changes	last 2026-10-16 · 3 revisions tracked
Claim id	dragonfly-worst-case-diameter-google-ocs-cuts-a

Where the guide uses it

8.5 Scale-Out Topology, Sizing & Oversubscription

← Full numbers register — every date-stamped figure in the guide, with revision history.