Failover

Goal

To use the Digi 6350-SR/6355-SR cellular modem as a backup WAN connection for the primary WAN Ethernet port. The Digi 6350-SR/6355-SR will use the WAN Ethernet port as its main Internet connection, and will fail over to the cellular modem if the primary connection goes down.

Setup

This article assumes the LAN ports are operating under default settings, which provide DHCP connectivity to devices connected to the Digi 6350-SR/6355-SR LAN ports. For details on Digi 6350-SR/6355-SR default settings, see the Digi 6350-SR/6355-SR User Guide. For details using aView to configure the Digi 6350-SR/6355-SR, see aView User Guide.

For this setup, you will need the Digi 6350-SR/6355-SR with both a primary WAN Ethernet connection, and a cellular modem connection.

Sample

The sample configuration below shows a Digi 6350-SR/6355-SR with two internet connections. The WAN Ethernet interface will be used as the primary Internet connection. The Digi 6350-SR/6355-SR is set up to test the WAN Ethernet connection twice every minute. If three sequential tests fail, then the Digi 6350-SR/6355-SR will restart the WAN Ethernet connection and fail over to the cellular modem's Internet connection until the WAN Ethernet connection is re-established.

Summed up, if a Digi 6350-SR/6355-SR primary WAN connection fails, with the configuration below the Digi 6350-SR/6355-SR will fail over to the cellular modem in under 2 minutes.

Sample configuration

Open the configuration profile for the Digi 6350-SR/6355-SR and make the following changes.

In the Modem -> Metric entry, ensure the value is set to a number higher than the the value in Network -> Interfaces -> WAN -> IPv4 -> Metric. The interface with the lower metric takes higher precedence. By default, the cellular modem metric should be 3 and the WAN Ethernet's metric should be 1, making WAN Ethernet the primary and the cellular modem the backup Internet connection.