Select a Nokia 7750 SR-1s 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 tmnxChassisTotalNumber under the tmnxChassisObjs branch of TIMETRA-CHASSIS-MIB, then select it and click OK. It reports the number of chassis currently installed in this system — normally a fixed value such as 1 for a single-chassis deployment. 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 an INTEGER-type OID, Value bounds is the most useful condition here — trigger an alert if the value changes from its expected baseline (e.g. moves away from 1), since that would indicate an unplanned change to the chassis configuration. Click Finish to create the monitor; you can adjust any parameter later.