An index to the Loss Measurement Configuration table which indicates
the specific measurement session for the MEP.
jnxSoamPmMepOperNextIndex needs to be inspected to find an
available index for row-creation.
Referential integrity is necessary, i.e., the index needs to be
persistent upon a reboot or restart of a device. The index
is never reused for other PM sessions on the same MEP while this
session is active. The index value keeps increasing until it
wraps to 0. This is to facilitate access control based
on a fixed index for an EMS, since the index is not reused.