This value must contain the interface index of the
outgoing interface. This object may only take the
value of 0 during the create-and-wait row creation
operation if the management station has not yet set
the value of this object. This object cannot be
modified if mplsOutSegmentRowStatus is active(1).
The mplsOutSegmentRowStatus cannot be set to
active(1) until this object is set to a value
corresponding to a valid ifEntry.