+vif\_type
+ Valid for the Xen HVM hypervisor.
+
+ This parameter specifies the vif type of the nic configuration
+ of the instance. Unsetting the value leads to no type being specified
+ in the configuration. Note that this parameter only takes effect when
+ the 'nic_type' is not set. The possible options are:
+
+ - ioemu
+ - vif
+