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NetComm Wireless NTC-30WV 3G Outdoor Router with Voice
www.netcommwireless.com
Ver 1.6
Link monitor
By default, an interface is monitored by its link status. This means that the router switches to the WWAN (Profile1) interface when
the physical link to eth.0 is broken (i.e. the cable is disconnected or some other hardware fault causes the physical connection to
fail). If this is your preferred method of monitoring, select the Hardware link option and click the Save button to complete the
configuration.
Ping monitor
Alternatively, controlled ping packets can be used to determine the status of the link. These are small packets of data that the router
sends to a remote address and if the connection is healthy, a reply is received. They are sent indefinitely at regular intervals that you
specify. For each WAN interface that is ping monitored, you may specify two separate internet addresses and interval timers for the
tests.
Each WAN interface is independently monitored according to its own distinct settings, following the process outlined below.
a)
At a regular interval stipulated by the Periodic ping timer setting, the router sends 3 ping requests via the interface to both
the first and second destination addresses simultaneously. If it receives a reply to any of those pings, it deems the
connection to be healthy and continues pinging them at the Periodic ping timer interval.
b)
If the router does not receive a response to all six pings by the start of the next Periodic ping timer interval, it registers this
failure as a Fail count and continues to send pings to both destination addresses at the Retry timer interval (typically set at
a shorter interval than the Periodic ping timer since there may be a problem). If a response is received to any of those
pings, the router returns to sending pings according to the Periodic ping timer setting.
c)
However, if after another period defined by the Retry timer setting the router again does not receive a response to any of
the pings, it registers another Fail count.
d)
The router repeats the retry process until it either receives a ping response (and returns to testing the interface according
to the Periodic ping timer) or the number configured in the Fail count field is reached. In the latter case, that ping
monitored interface is marked as unavailable, at which point the router automatically reroutes packets according to the
configured priorities of the remaining WAN interfaces.
e)
The process for returning an unavailable interface to an available state is similar to the above process. When an interface is
marked unavailable by the ping monitor, the router continues to retry pings to the two destination addresses via that
interface according to the Retry timer setting until it receives a 100% successful response to the six pings before the next
retry. The router then switches to the Periodic ping timer interval, waiting for 100% successful responses for an amount of
consecutive periods that equal the configured Fail count setting, at which point the WAN interface is marked available.
