Its me here,
http://msdn.microsoft.com/en-us/library/windows/desktop/aa814083(v=vs.85).aspx
Plug and Play Extensions (PnP-X) enable a computer system to discover networked devices and to install them on the local system using Plug and Play (PnP). For more information about PnP-X, see
Windows Rally.
Each PnP-X device has an associated
function instance. A list of PnP-X function instances is stored in the PnP-X association database. If a device has an associated entry marked in the association database and the device is currently online (on the network), the PnP
devnode for the device is marked present on the system, and the associated device is available for use. If a device does not have an associated entry marked in the association database, no PnP
devnode will exist on the system and the device is not available for use.
Best Wishes - Eric