Below is an example screenshot of the Threshold control screen in Monitor one. The example shows a Threshold Shooter (Port_has_changed) that monitors all ports of a switch (sw20) for changes in port-status (compared with the status of the first sample). Just as an example I disconnected the UTP cable from port 20 and connected it to port 21.
In the example above, the Threshold Shooter was monitoring a 24-ports HP2524 workgroup switch which makes monitoring changes in port status not very useful. In backbone environments however, with a lot of redundancy, it is very important to monitor the status of individual ports of routers and/or switches.