This object represents an arbitrary local integer value
used by this agent to identify a particular connection
instance, unique only for the indicated local connection
endpoint.
A particular ptopoConnIndex value may be reused in the event
an entry is aged out and later re-learned with the same (or
different) remote chassis and port identifiers.
An agent is encouraged to assign monotonically increasing
index values to new entries, starting with one, after each
reboot. It is considered unlikely that the ptopoConnIndex
will wrap between reboots.