Certain types of iSCSI adapters depend on the VMkernel networking. These adapters include the software or dependent hardware iSCSI adapters, and the VMware iSCSI over RDMA (iSER) adapter. If your environment includes any of these adapters, you must configure connections for the traffic between the iSCSI or iSER component and the physical network adapters.
Configuring the network connection involves creating a virtual VMkernel adapter for each physical network adapter. You use 1:1 mapping between each virtual and physical network adapter. You then associate the VMkernel adapter with an appropriate iSCSI or iSER adapter. This process is called port binding.
Follow these rules when configuring the port binding:
You can connect the software iSCSI adapter with any physical NICs available on your host.
The dependent iSCSI adapters must be connected only to their own physical NICs.
You must connect the iSER adapter only to the RDMA-capable network adapter.
For specific considerations on when and how to use network connections with software iSCSI, see the VMware knowledge base article at http://kb.vmware.com/kb/2038869.