The administrative state of PIM on this interface.
When the status of this object is set to 'adminStatusDown', no
PIM messages will be sent or received on this interface. The
TIB state pertaining to this interface is cleared, resulting in
the removal of the associated routes from the MFIB.
When the status of this object is set to 'adminStatusUp', normal
PIM operation will proceed, and multicast state is stored in the
TIB when it is learned.