What are OSFP modules and how are they used?
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✓ Best Answer
OSFP (Octal Small Form-factor Pluggable) is a newer optical module standard for 400G and 800G speeds.
OSFP Basics
- 8 electrical lanes at 50/100 Gbps each
- Slightly larger than QSFP-DD (18.35×14.5×107mm)
- Higher power capability (up to 15W native, 25W with cooling)
- Built-in heat sink option
OSFP vs QSFP-DD
| Feature | OSFP | QSFP-DD |
|---|---|---|
| Size | Slightly larger | QSFP form factor |
| Lanes | 8 | 8 |
| Max power | 15W (25W enhanced) | 7-14W |
| Backward compat | No | QSFP+/QSFP28 fit |
| Heat sink | Integrated | External |
OSFP Variants
- 400G-DR4: 500m over parallel SMF
- 400G-FR4: 2km over duplex SMF (WDM)
- 400G-LR4: 10km over duplex SMF
- 400G-ER4: 40km over duplex SMF
- 800G-DR8: 500m over 8-fiber SMF
OSFP Deployment
- Nvidia (Mellanox) prefers OSFP
- Some data center networking vendors use OSFP
- Common in AI/ML clusters (InfiniBand HDR/NDR)
QSFP-DD Adoption
- QSFP-DD has broader ecosystem
- Most cloud DC vendors chose QSFP-DD
- Cisco, Arista, Juniper standardized on QSFP-DD
Technical Trade-offs
- OSFP: Better thermal design, more power headroom
- QSFP-DD: Better port density, backward compatibility
- Choice often driven by vendor ecosystem
800G Future
- Both OSFP and QSFP-DD800 supporting 800G
- OSFP-XD (extreme density) coming
- 1.6T on horizon with 200G/lane technology
Practical Advice
- Match module form factor to switch selection
- OSFP for InfiniBand HDR/NDR fabrics
- QSFP-DD for Ethernet data center switches
- Both will coexist for years
2 Other Answers
14
OSFP wins in AI clusters, QSFP-DD dominates general data center. Different worlds.
10
Thermal capacity matters at 800G. OSFP has advantage there.
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