The LSR can be configured to use either conservative or liberal
label retention mode.
If the value of this object is conservative(1) then advertized
label mappings are retained only if they will be used to forward
packets, i.e. if label came from a valid next hop. If the value of
this object is liberal(2) then all advertized label mappings are
retained whether they are from a valid next hop or not.
Current release of MPLS does not provide support to assign
this MIB object with a value 'liberal'.