Polling is the active watching, or monitoring, of your network with WhatsUp Gold. This is done in a variety of ways, depending on the service monitors you have configured on your devices. The default polling method is accomplished through Internet Control Message Protocol (ICMP). The default polling interval for WhatsUp Gold is 60 seconds.
A small amount of data is sent from the WhatsUp Gold computer across the network to the device it is watching. If the device is up, it echoes the data back to the WhatsUp Gold computer. WhatsUp Gold considers a device is down when it does not send the data back.
It's important to note that polling interval settings affect how WhatsUp Gold determines a specific device state. For example, if a user has specified that she only wants to poll a device every 5 minutes, WhatsUp Gold will only recognize device state changes at the 5 minute polling intervals. If a device has been down 2 minutes, it will be recognized as down when the 5 minute polling interval occurs. Corresponding Up actions will be triggered after the 5 minute poll occurs rather than when the device went down at the two minute point.
The device polling interval affects the way WhatsUp Gold determines the specific device state. When a device transitions from Up to Down, it checks to determine the last time the device was Up. For example, with the default polling interval of 60 seconds, when a device goes down it looks back and determines that the last time it was up was 63 seconds ago so it goes from "Up at least 5" to "Down." In the next polling interval when the device still returns down, WhatsUp Gold looks backward and determines that the last Up time was 125 seconds ago so it now is "Down at least 2 minutes."
If a 5 minute polling interval is set, the first time that a device returns down, WhatsUp Gold looks back and determines that the last time the device was up was 304 seconds ago so it transitions directly from "Up at least 5 minutes" to "Down at least 5 minutes" (skipping the Down and Down 2 states). Similarly, when the device comes back up, WhatsUp Gold looks back to determine the last time the device was Down and it registers that it was 301 seconds ago so it transitions directly from "Down at least 5" to "Up at least 5 minutes."
In short, if you plan to use polling intervals longer than the default of 60 seconds, we recommend that you associate actions with device states that will not be skipped because of the extended polling interval.