The table is used to get free indexes of tables to create
new entries. The algorithm for free indexes depends on
table's type:
Tuple table - first free index.
Offset table - first free index.
ACE table - last used index + ACE indexes delta.
ACL table - first free index.
Class Map table - last used index + Class Map indexes delta.
Policy Map table - first free index.
Policer Table - first free index.
The ACE indexes delta and Class Map indexes delta are used
to supply QoS MIB user easy insert entry capabilities.
Values of these deltas depend on the MIB implementation.
The 'Get and increment' approach is used in all cases.