Number of devices per QSFP+ port

Hi,

I am planning to buy a network card for a new academic research server, which will be used in a SFP+ environment. I would like to evaluate the X520-DA2 (SFP+) and the X520-QDA1 (QSFP+).

I wonder if a X520-QDA1 card can be directly linked with two different SFP+ devices simultaneously, using a Direct Attach cable, such as the X4DACBL3, that provides 4x10 GbE connections.

If that is correct, how many network devices/interfaces will be available at OS level.

From the ixgbe driver's README:

"- 82599-based QSFP+ adapters only support 4x10 Gbps connections.

  1x40 Gbps connections are not supported. QSFP+ link partners must be

  configured for 4x10 Gbps."

Does it mean that the card provides four interfaces (i.e, eth0, ... eth3)?

Best,

Topo