NetModule NB3700 User Manual page 30

In general, a link will be only dialed or declared as up if the following prerequisites are
met:
Condition
Modem is registered
Registered with valid service type X
Valid SIM state
Sufficient signal strength
Client is associated
Client is authenticated
Valid DHCP address retrieved
Link is up and holds address
Ping check succeeded
The menu can be used further to prioritize your WAN links. The highest priority link
which has been established successfully will become the so-called hotlink which holds
the default route for outgoing packets.
In case a link goes down, the system will automatically switch over to the next link in
the priority list. You can configure each link to be either established when the switch
occurs or permanently in order to minimize link downtime.
Parameter
1st priority
2nd priority
3rd priority
4th priority
Links are being triggered periodically and put to sleep in case it was not possible to
establish them within a certain amount of time. Hence it might happen that permanent
links will be dialed in background and replace links with lower priority again as soon as
they got established. In case of interfering links sharing the same resources (for instance
in dual-SIM operation) you may define a switch-back interval after which an active
hotlink is forced to go down in order to let the higher-prio link getting dialed again.
NB3700 User Manual 3.8
WWAN WLAN ETH
X
X
X
X
X
X
WAN Link Priorities
The primary link which will be used whenever possible.
The first fallback link, it can be enabled permanently or
being dialed as soon as Link 1 goes down.
The second fallback link, it can be enabled permanently or
being dialed as soon as Link 2 goes down.
The third fallback link, it can be enabled permanently or
being dialed as soon as Link 3 goes down.
30
PPPoE
X
X
X
X X X
X X X
X X X