The optics industry measures progress in generations of port speed. Each generation doubles throughput per port and requires substantially more sophisticated signal engineering.
Optics speed roadmap — click a generation
Each generation maps to specific DGX hardware and form factors
Fiber plant: OM4 supports 400G, 800G, and 1.6T — only transceivers and switch ports change between generations. Plan fiber for 10 years. Plan transceivers and switches for a 3-year refresh cycle.
The current landscape, as of 2026:
400G per port -- the H100 DGX baseline. Every ConnectX-7 NIC on a DGX H100 node runs at 400G. Every OSFP port on the SN5600 leaf switch runs at 400G. This generation is mature and widely deployed. Supply is stable, costs are falling. 400G pluggable optics are the anchor of every AI cluster in production today.
800G per port -- the B200 and GB200 (Blackwell) era. These next-generation DGX systems expose 800G on their NIC ports, requiring switches with 800G QSFP-DD or OSFP ports on the downlink side. 800G is ramping fast. According to Dell'Oro Group's 2025-2026 forecasts, 800G is the fastest-growing segment in the AI networking market. Nearly all hyperscalers have moved or are moving to 800G as their baseline for new deployments.
1.6T per port -- early ramp beginning in 2026. The technology was demonstrated at industry events in 2025. Volume production is limited to select NVIDIA and hyperscale deployments, with broader availability expected through 2026-2027. 1.6T is based on 8 x 200G lanes using the 448G PAM-4 standard, and uses a new form factor -- OSFP-XD (OSFP Extended Density). The Open Compute Project has standardised OSFP-XD as the primary 1.6T carrier.
3.2T per port -- demonstrated in 2025, commercial deployments expected by 2026-2027. Uses 16 lanes at 200G each. This generation requires infrastructure built to OSFP-XD density and is primarily relevant for planning longer-term cabling plant investments.
The mapping between DGX generations and optics generations is direct:
| DGX generation | GPU | NIC per GPU | NIC port speed | Switch port |
|---|---|---|---|---|
| DGX A100 | A100 SXM4 | ConnectX-6 | 200G HDR IB | 200G |
| DGX H100 | H100 SXM5 | ConnectX-7 | 400G NDR IB or 400GbE | 400G OSFP |
| DGX H200 | H200 SXM5 | ConnectX-7 | 400G | 400G OSFP |
| DGX B200 (Blackwell) | B200 | ConnectX-8 | 800G | 800G OSFP |
| B300 era (projected) | B300 | ConnectX-9 | 1.6T | 1.6T OSFP-XD |
The implication for infrastructure decisions: if you are installing a cabling plant today, the fiber runs you lay and the patch panel infrastructure you build will serve multiple optics generations. The physical fiber is not the constraint -- OM4 fiber that supports 400G will support 800G and 1.6T with upgraded transceivers. What changes per generation is the pluggable module, the switch port, and the cabling end connector type.
Plan fiber infrastructure for a 10-year lifetime. Plan transceivers and switches for a 3-year refresh cycle.