2 ways to identify which type of NIC cards are installed on your VxRail and check their connection status.
1 – ESXi Shell
esxcli network nic list
If you wish to gather additional info via esxcli:
esxcli network nic get -n vmnic#
2 – iDRAC
iDRAC -> System -> Overview -> Network Devices
In this example the NIC Type is an Intel X710 10Gb QP. It is always worth refencing the intel support matrix in terms of supported SFP’s, for this particular NIC X710 here is the matrix (thanks @JeremyMerrill for the pointer):