Question 1: How do I choose between using OSFP and QSFP-DD for 400G?
Answer: It Depends on your future speed requirements, and your ability to handle the heat.
The two main reasons are:
- Backwards compatibility with QSFP56
- Thermal management
Backwards compatibility:
QSFP-DD ports can accept QSFP56 and QSFP112 transceivers too if needed - but note that this wont work the other way, for a 400G QSFP112 port to take a 400G QSFP-DD transceiver etc.
You can not put any other transceiver form factor into an OSFP port however without special adapters, but you could always use breakout cables if you need to use an OSFP switch with QSFP NICs, with the bandwidth splitting too.
For OSFP you're better set for upgrades towards 1.6T and beyond, with upcoming 16-lane OSFP-XD modules which will be backwards compatible with current OSFP form factors (both flat top and finned I presume)
Thermal management:
OSFPs are physically larger and can come with flat top or finned top form factors. This is partly due to having more space as they were designed around 8 lanes from the start, whereas QSFP-DD are designed to fit 8 lanes in a sort of 4 lane compatible form factor.
This means that with #QSFP-DD, the switch itself must have heatsinks built into the ports to help keep the module cool, but with OSFP, the modules have heatsinks built into them.
In the further, for #OSFPs, they come in slightly shorter flat top form factors which are intended for low port density appliances like servers, as well as finned top form factors for high port density switches.
If you have more questions, please consult the following link：
https://www.univiso.com.cn/contact/
Email: sales1@szuniviso.com
