What's actually in an AI rack — and who sells it
A layer-by-layer walk through a modern AI training rack, and the vendor competing at each layer. Written from the lab side.
Most people who sell into AI infrastructure have never opened a rack. I spent a summer in a hardware lab doing exactly that, and the thing that struck me was how many separate companies have to agree on a standard for one cabinet to work at all.
This is a walk through the rack from the bottom up, and the commercial question sitting on top of each layer.
The rack itself
TODO — Open Rack V3. What the OCP spec standardizes and why it exists. The short version: hyperscalers got tired of every vendor shipping a different mechanical standard, so they wrote one.
Your angle: you sourced one. Write about what is hard to find, what the lead times look like, and who the actual suppliers are.
Who sells it: TODO
Commercial read: TODO — when the mechanical layer is standardized, differentiation moves up the stack. That is worth saying out loud.
Power delivery
TODO — the busbar. Why DC bus distribution replaced per-server PSUs, what changes at 48V, and what a power shelf does.
Who sells it: TODO
Commercial read: TODO
Thermal
TODO — this is your strongest section because you commissioned a CDU. Cover why air cooling runs out of room, what a coolant distribution unit actually does, and what the failure modes are that nobody mentions in the marketing.
Who sells it: TODO
Commercial read: TODO — the switch to liquid changes who the buyer is inside the customer. That is a real GTM consequence, not a technical footnote.
Compute
TODO — GPU and accelerator trays. Keep this shorter than you want to. Everyone writes about this layer and you have less to add here than anywhere else.
Who sells it: TODO
Commercial read: TODO
Connectivity
TODO — the interconnect layer. PCIe and CXL retimers, Ethernet, optics, and why moving data between accelerators became the bottleneck.
Be careful here. This is the layer your employer works in, so keep strictly to public material and do not editorialize about competitors.
Who sells it: TODO
Commercial read: TODO
Networking and cabling
TODO — top-of-rack switching, DAC versus AOC versus optical, and the part everybody underestimates, which is that somebody has to physically route all of it.
Who sells it: TODO
Commercial read: TODO
What I took from this
TODO — three or four sentences. The honest conclusion, not a summary.
The version I would defend: the hard part of this market is not any single component, it is that the buyer has to integrate six vendors who each think they are the important one. Whoever makes that integration easier wins the account.