1. Background
Entering the 800G era, QSFP-DD and OSFP are the two dominant form factors, each with trade-offs.
2. QSFP-DD
Backward-compatible with QSFP28 (4-channel), extended to 8 channels (PAM4). Mature ecosystem, huge installed base in data centers, broad vendor support.
3. OSFP
Standalone 8-channel design with stronger thermal headroom (supports 800G/1.6T), slightly larger footprint, suited for high-power coherent and future 1.6T evolution.
4. Comparison
- Density: QSFP-DD offers slightly higher faceplate density (compatible with legacy panels).
- Thermal: OSFP is superior for high-power modules.
- Ecosystem: QSFP-DD is more mature; OSFP is future-oriented.
5. Recommendation
Prioritize compatibility/ecosystem: QSFP-DD. Prioritize thermal/future evolution: OSFP. Both support 400G/800G.
