Most engineers evaluating 800G or 1.6T optical modules focus on reach, power budget, connector types, and interoperability.
However, thermal design is becoming just as important.
As optical module power consumption rises, two thermal architectures have emerged inside the OSFP ecosystem:
- OSFP-IHS
- OSFP-RHS
OSFP-IHS
Integrated Heat Sink (IHS) modules include cooling fins directly on the module.
Advantages:
- Compatible with standard OSFP cages
- Mature ecosystem
- Easy deployment
- Well suited for air-cooled switches
OSFP-RHS
Riding Heat Sink (RHS) modules remove the integrated heatsink and rely on the host platform for cooling.
Advantages:
- Lower profile design
- Better integration with cold plates
- Suitable for liquid-cooled environments
- Higher long-term thermal scalability
A Common Misconception
Many engineers assume IHS and RHS are simply different cooling options.
They are not.
The mechanical design differs significantly.
An RHS module requires a host platform designed specifically for RHS deployment.
Compatibility should always be verified before purchasing transceivers.
Where the Industry Is Heading
The rapid growth of AI infrastructure is pushing thermal management beyond component-level optimization.
Future networking platforms will increasingly rely on system-level cooling strategies where optics, compute, and networking hardware share the same thermal architecture.
Understanding IHS and RHS today can help avoid costly redesigns later.
For a complete technical comparison, deployment examples, and thermal decision matrix, see the original engineering article:
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