The VPI (ConnectX-3 and ConnectX-3 Pro) cards can run InfiniBand on the link layer, while the EN cards cannot.
RDMA is supported on both types (VPI and EN). if you use EN you can run RoCE.
The ConnecX-3 Pro (EN or VPI) can run RoCE v.2 (routable) while the ConnecX-3 cannot.
If you don't need to pass router, you may be good with RoCE v1 setup (not rotatable).
What is your WAN connectivity? is it 10GbE?
What about security?
The SX1036 can be configured as a router as well.
What L2/L3 protocols are you running?
Thanks,
Ophir.