AI interconnects & optics

AI clusters connect GPUs with either InfiniBand or high-speed Ethernet. Both push the optics to the fastest modules in production.

InfiniBand vs Ethernet (RoCE)

Both are valid choices; many large clusters use InfiniBand, while Ethernet+RoCE is growing quickly for AI at scale.

Rates and modules

• 400G — QSFP-DD or OSFP, built from 4×100G or 8×50G lanes.
• 800G — OSFP or QSFP-DD800, typically 8×100G lanes.

The rate and lane count set the form factor; InfiniBand generations and their per-lane rates are in InfiniBand speeds.

Reach types

Inside a rack, short DR/SR optics or direct-attach and active cables dominate; between rows, FR/LR single-mode optics carry the longer hops. High density means a single switch can host hundreds of these modules.

Whatever the reach, these modules carry standard managed memory — CodingBox reads their identity and DDM to verify a link before it joins the fabric.