Description: This table contains Selector Functions connected to a
Metering Process by the index ipfixMeteringProcessCacheId.
The Selector Functions are grouped into Selection Processes
by the ipfixSelectionProcessIndex.  The Selector Functions
are applied within the Selection Process to the packets
observed for the given Metering Process cache in increasing
order as indicated by the ipfixSelectionProcessSelectorIndex.
This means Selector Functions with a lower
ipfixSelectionProcessSelectorIndex are applied first.
The remaining packets are accounted for in Flow Records.

Since IPFIX does not define any Selector Function (except
selecting every packet), this is a placeholder for future
use and a guideline for implementing enterprise-specific
Selector Function objects.

The following object tree should help the reader visualize
how the Selector Function objects should be implemented:

ipfixSelectorFunctions
|
+- ipfixFuncSelectAll
|  |
|  +- ipfixFuncSelectAllAvail (is the function available?)
|
+- ipfixFuncF2
|  |
|  +- ipfixFuncF2Avail (is the function F2 available?)
|  |
|  +- ipfixFuncF2Parameters (a table with parameters)
...
|
+- ipfixFuncFn...

If a Selector Function takes parameters, the MIB should
contain a table with an entry for each set of parameters
used at the Exporter.