This index is used as a secondary index to uniquely
identify this row. Before creating a row in this table,
the 'jnxMplsLdpEntityIndexNext' object should be retrieved.
That value should be used for the value of this index
when creating a row in this table. (NOTE: if a value
of zero (0) is retrieved, that indicates that no rows
can be created in this table at this time.
A secondary index (this object) is meaningful to some
but not all, LDP implementations. For example
in an LDP implementation which uses PPP would
use this index to differentiate PPP sub-links.
Another way to use this index is to give this the
value of ifIndex. However, this is dependant
on the implementation.