Part of the day: Scale-up fabric

Assembled by the nightly build from this catalog’s own entry for Scale-up fabric (3.01, Layer 3 — Networking & interconnect). The tables below are rebuilt every night; first published 2026-09-04, refreshed 2026-09-24.

The fabric linking GPUs to each other inside a single rack or pod, separate from the switching fabric that connects racks to each other.

Scale-up fabric is the shortest, highest-bandwidth network in the data center: it lets GPUs inside the same rack or pod address each other’s memory directly, rather than going through the scale-out switch fabric (3.02, 3.03). It sits upstream of the copper spine and backplane cartridges (3.10) that physically wire it together and, at higher speeds, of the optics and co-packaged approaches (3.04, 3.08) being evaluated as a copper replacement. AI training and inference workloads that split a single model across many accelerators depend on this fabric scaling in lockstep with GPU count, since it sets the ceiling on how large a tightly coupled GPU domain can get. An investor should watch whether a proprietary approach keeps its lead over open alternatives being pushed by a wider industry consortium, since that split determines how concentrated the supplier base for switch chips, cables, and connectors stays as pod sizes grow.

AI delta: Larger AI models split across more GPUs per training or inference job, which raises the bandwidth and reach demanded of the scale-up fabric linking them inside a rack or pod.

Who makes it

The full entry — sub-categories, news, videos and sources — lives on the Scale-up fabric page.