N_Port_ID Virtualization (NPIV) is a method for virtualizing a FibreChannel Port. With NPIV, one physical FibreChannel port can obtain many N_Port_IDs.
Why is this useful? The reason most people mention is to map one virtual N_Port_ID to one guest operating system in a virtual environment. So, your Xen DOMU or Logical Domain DOMA can have its own N_Port_ID, just as if it were a physical HBA. With this N_Port_ID and the related port and node world wide name (PWWN/NWWN), storage administrators can use existing zoning and LUN masking techniques they've used in the past.
