About Dual Wan Configuration; Failover; Connectivity Monitoring - Digi 6350-SR User Manual

Dual WAN configurations

About dual WAN configuration

The Digi 6350-SR/6355-SR is a Dual-WAN device, meaning it has two interfaces capable of providing
Internet access by default -- its WAN Ethernet port and the plug-in cellular modem -- though additional
LAN ports may even be reconfigured for supplemental Internet access. Active WAN connections can
provide both failover and load balancing per user-defined parameters.

Failover

By default, this allows the plug-in modem to serve as a secondary (backup) WAN that becomes the
active connection once the Ethernet WAN port is detected as offline. The Digi 6350-SR/6355-SR then
monitors the offline connection to see when it comes back online, which prompts the backup interface
to once again become inactive.
Each interface has a Metric value associated with its IPv4 configuration. The example on the left of
this page is associated with the WAN interface, which will take priority over all other interfaces by
default (as seen by its Metric value of 1).

Connectivity monitoring

Note Both tests are set via the default group config in aView—it is not built into the firmware.
Devices that have not synced with aView will not have these tests enabled by default.
To properly trigger a failover (or failback) scenario, test parameters must be defined to monitor the
primary connection. Both a Ping and HTTP test come built into the Digi 6350-SR/6355-SR WAN port
configuration by default. After 4 failed attempts, the secondary connection will take over Internet
access for the Digi 6350-SR/6355-SR. Similarly, the monitoring tests trigger the restoration of the
primary WAN connection when they detect that the interface with a higher metric has come back up.
Note Best practices dictate that redundant tests (with divergent failure conditions) will be the best
way to ensure proper connectivity monitoring and active recovery. With only a single test type, false
positives could be reported. Two different tests are recommended to prevent false positives.
Digi 6350-SR/6355-SR LTE Router User Guide
About dual WAN configuration
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