The WatchDog continuously monitors whether a given process or a part of a system work as they should. If not, the WatchDog restarts the process.
In the intelligent power outlets NETIO there is Watchdog function
The notion of "IP WatchDog" refers to the method of detecting if an IP device works correctly. IP devices are usually monitored using ICMP PING replies. A device is considered to be functioning if it is connected to the network and responds to PING requests. If a reply to a PING request fails to arrive (within a specified time or after a certain number of retries), the IP Watchdog restarts the device (by disconnecting the power for a short time).
In general, the IP WatchDog function replaces a human who would have to travel several miles (or hours) to the site just to flip the power switch off and on. With IP WatchDog, the device is power-cycled without human intervention. Often, end users don¡¦t even notice that something was not working.
In the context of LAN / WiFi network products, IP Watchdog detects the functioning as well as the network connection. This way, the basic functioning of the device is checked together with the network elements (microwave links, routers, switches) along the route.
This function is sometimes referred to as Autoping or Heartbeat / PING Heartbeat.
Each output has its own IP Watchdog function (one IP address for each output).
Note: A PING reply does not guarantee that the tested device is functioning as it should. For example, an IP surveillance camera with a lens or image encoding problem can still reliably respond to PING over the network.
In the context of AVIOSYS products
AVIOSYS devices include an integrated IP WatchDog function that can be used to check the availability of another device in the network using the "ping" command (ICMP protocol). If the WatchDog function does not receive a response within a specified time, it power-cycles the socket (Short Off) to reboot the connected device.
To detect the failure of a single device, it is sufficient to specify the IP address of this device.
To watch a connection to a network (e.g. to verify the functioning of a microwave link), we recommend to monitor PING responses from two different IP addresses. This will prevent WatchDog from restarting an otherwise perfectly working Internet connection over and over if one particular device is down.
The AVIOSYS IP WatchDog implementation can deactivate itself after several restarts. If the restart didn¡¦t help and the target is still unreachable (the Internet connection was not re-established), it may be pointless to restart the connected device over and over again.