This enumerated INTEGER reports the I/O port (bus) type of a specific disk, such as fibrechannel, iscsi, or fibrechanneloverethernet. An admin uses it to understand what physical connectivity a given drive uses when planning maintenance or diagnosing a connectivity issue specific to one bus type. Knowing a problematic disk uses fibrechanneloverethernet, for instance, would point the admin toward checking FCoE-specific switch configuration rather than a native Fibre Channel fabric.