Hi Morihisa,
We don't support the splitting of the 40GbE adapter port to 4 ports of 10GbE.
What I'm saying is that if you just want to reduce the speed from 40GbE to 10GbE, there are simple ways to do it (e.g. using QSA or 40 to 10GbE cable).
The main target of this cable is to connect 4 10GbE adapter ports to 40GbE switch port.
Could you share with me your setup or problem you need to solve, I will try to help you on that.
Why do you need to split the 40GbE adapter port, what is the application?
Thanks,
Ophir.