Coordinates ifIndex value allocation for entries in the
usdMplsIfMinorTable. A GET of this object returns the next available
ifIndex value to be used to create an entry in the associated interface
table; or zero, if no valid ifIndex value is available. This object
also returns a value of zero when it is the lexicographic successor of a
varbind presented in an SNMP GETNEXT or GETBULK request, for which
circumstance it is assumed that ifIndex allocation is unintended.
Successive GETs will typically return different values, thus avoiding
collisions among cooperating management clients seeking to create table
entries simultaneously.