How do the two ports on a fast NIC usually get used?

Hi,

I am working on the client side of RDMA for NFS.
For the OFED connect, the client needs to provide
an IP address to identify which NIC port to use.

I currently have the code working, using
fib4_lookup()/fib6_lookup() to find the address for
the NIC for the subnet.
--> This seems to work ok if only one of the ports
      on the fast NIC that can do RDMA is configured
      for the subnet of the NFS server.

What I am wondering is how people typically use the
two ports that these NICs often have?
--> I doubt RDMA can work if the ports are lagg'd to-gether,
      but I do not know for sure?

Basically, I am wondering if I need to add an NFS mount
option that specifies the NIC's IP address, so that it can
always "find" the correct NIC/port?

Thanks in advance for any info, rick