Select a device implementing PIM-STD-MIB as the target host to create a monitor — the SNMP service should be up and running on it. Click New Monitor, then check SNMP Custom on the Favorites tab, click Next, and confirm the host. On the next page, click Select... to open the built-in SNMP MIB Browser and locate pimNeighborUpTime under the pimNeighborEntry branch of PIM-STD-MIB, selecting the specific row/instance you want to monitor since this is a table column, then select it and click OK. It reports, in TimeTicks, how long this PIM neighbor relationship has been up. On the monitor's Main parameters page you can set the target's SNMP port (default 161), credentials, polling interval, and other settings — see the SNMP Monitor help for details. On the State conditions and Alerting tabs, configure when the monitor should change state and trigger an alert; since this is a TimeTicks-type OID, Value bounds is the most useful condition here — trigger an alert if the uptime resets to a small value unexpectedly, which indicates the PIM adjacency to that neighbor was recently lost and re-established. Click Finish to create the monitor; you can adjust any parameter later.