Field notes
The unglamorous truth of big AI: the network decides how much of your billion-dollar cluster you actually get to use. The war to follow is copper empire versus open Ethernet — NVIDIA's private fabrics against everyone else's shared standard.
Start with these three
N&
NVLink & NVSwitch
NVIDIA's deepest moat, cast in copper. The reason 72 GPUs can act as one.
UE
Ultra Ethernet
The industry's collective answer, published as one open spec in 2025.
8&
800G & 1.6T Optics
Where the money quietly goes — clusters consume these by the hundred thousand.
Interconnects & fabrics
9
N&
NVLink & NVSwitch
NVIDIA's scale-up fabric: what makes 72 GPUs one computer.
IN
InfiniBand
The low-latency training fabric NVIDIA acquired with Mellanox.
8&
800G & 1.6T Optics
The pluggable transceivers AI clusters consume by the hundreds of thousands.
CP
Co-Packaged Optics
Light brought onto the switch package — the next power saver.
PE
PCI Express
The universal socket: how accelerators, NICs and CPUs meet.
R(
RoCE (RDMA over Ethernet)
The transport trick that lets ordinary Ethernet move GPU memory.
SX
Spectrum-X Ethernet
NVIDIA's answer to losing Ethernet: an AI-tuned Ethernet of its own.
UA
UALink
The open scale-up standard: everyone-but-NVIDIA's answer to NVLink.
UE
Ultra Ethernet
The industry consortium rebuilding Ethernet for AI — 1.0 spec shipped 2025.
Networking companies
14
AN
Arista Networks
The Ethernet switch leader of the AI back-end network.
AM
Amphenol
Connectors and cable assemblies in every server, switch and rack.
AL
Astera Labs
PCIe retimers and CXL connectivity inside nearly every AI server.
CA
Celestial AI
The Photonic Fabric: optical links from any chip to any memory.
CI
Ciena
Coherent optics linking AI data centers across cities and oceans.
Cisco
The networking incumbent pushing its own silicon into AI fabrics.
CO
Coherent
One of the largest makers of the optical transceivers AI clusters consume by the million.
CO
Corning
The fiber-optic cable itself — glass demand doubled by AI campuses.
CT
Credo Technology
Active electrical cables — the copper that wires racks together.
FA
Fabrinet
The contract manufacturer behind NVIDIA's optical transceivers.
LI
Lightmatter
Photonic interconnect — moving light into the chip package itself.
LU
Lumentum
Lasers and photonics for the optical layer of AI networks.
Nokia
Optical transport and data-center routing — with NVIDIA as a 2025 investor.
TC
TE Connectivity
The other connector giant wiring AI racks and power paths.
Cisco
The networking incumbent pushing its own silicon into AI fabrics.
CO
Coherent
One of the largest makers of the optical transceivers AI clusters consume by the million.
CO
Corning
The fiber-optic cable itself — glass demand doubled by AI campuses.
CT
Credo Technology
Active electrical cables — the copper that wires racks together.
FA
Fabrinet
The contract manufacturer behind NVIDIA's optical transceivers.
LI
Lightmatter
Photonic interconnect — moving light into the chip package itself.
LU
Lumentum
Lasers and photonics for the optical layer of AI networks.
Nokia
Optical transport and data-center routing — with NVIDIA as a 2025 investor.
TC
TE Connectivity
The other connector giant wiring AI racks and power paths.