User's Manual

Watchdogs

Watchdogs are features which monitor the router for anomalies and restart the router if an anomaly occurs preventing its normal

operation. When configured, the watchdogs feature transmits controlled ping packets to 1 or 2 user specified IP addresses to

confirm an active connection. If the watchdog does not receive responses to the pings after a specified number of failures, it will

reboot the device in a last resort attempt to restore connectivity.

We recommend using caution when implementing this feature in situations where the device is intentionally offline for a

particular reason, for example, when Dial-on-demand has been enabled. This is because the watchdog expects to be able to

access the internet at all times, and will always eventually reboot the router if access isn't restored by the time the various timers

expire and the fail count is reached.

It is due to the nature of the watchdog being a last resort standalone backup mechanism that it will continue to do its job and

reboot the device even when the Dial-on-demand session is idle, or the mobile broadband connection is disabled by the user.

Therefore, we recommended that you disable this feature if Dial-on-demand is configured or if the mobile broadband connection

will be intentionally disconnected on occasion.

The watchdog works as follows:

a) The router sends 3 consecutive pings to the first destination address at the interval specified in the Periodic PING

Timer field.

b) If all 3 pings to the first destination address fail, the router sends 3 consecutive pings to the second destination address

at the Periodic PING Timer interval.

c) If all 3 pings to the second destination address fail, the router sends 3 pings to the first destination address using the

Periodic PING Accelerated Timer interval.

d) If all 3 accelerated pings to the first destination address fail, the router sends 3 pings to the second destination address

at the Periodic PING Accelerated Timer interval.

e) If all 3 accelerated pings to the second destination address fail, the router registers this as a fail and returns to step C.

f) When the number of failures reaches the number configured in the Fail Count field, the router reboots. If any ping

succeeds, the router returns to step A and does not reboot.

Note: The Periodic Ping Timer should not be set to a value of less than 210 seconds to allow the router time to

reconnect to the cellular network following a reboot.

To disable the periodic ping reset monitor, set Fail Count to 0.

Figure 64 – Ping watchdog settings

NetComm Wireless CDMA M2M Router