What Is OSFP? Definition and Key Facts

OSFP (Octal Small Form-factor Pluggable) is a larger 400G/800G pluggable transceiver format with superior thermal headroom, used in AI clusters and coherent DCI links.

Glossary · Updated 2026-10-23 · 1 min read

OSFP (Octal Small Form-factor Pluggable) is a pluggable optical transceiver form factor designed for high-speed networks from 400G upward. Like QSFP-DD it uses eight 50 Gb/s PAM4 electrical lanes at 400G, but in a noticeably larger body with an integrated heatsink.

Key facts:

Dimensions: roughly 22.6 mm wide, 108 mm long, 13 mm thick — larger than QSFP-DD.
Density: about 32 ports per 1U panel.
Backward compatibility: none with QSFP-series modules; adapters are required and carry signal-integrity risk.
Power: supports modules up to roughly 25 W, making it the preferred platform for coherent 400G ZR/ZR+ and high-power 800G optics.
Future proofing: the same cage family extends to 800G and 1.6T.

OSFP is common in AI/ML cluster switches and data center interconnect (DCI) equipment where thermal headroom matters more than port density.