Coordinate ifIndex value allocation for entries
in usdBridgedEthernetIfTable.
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.