I have two WR11 cell modems (close to each other) with two different carriers. The WAN access to site is a Gateway/Firewall PC which only has 1 WAN port and multiple LAN ports. Due to the WAN port limitation I am thinking of addding an unmananaged switch to provide the connection point for WAN-LAN.
What configuration would be required at each modem to provide cellular-cellular failover? We also want to minimize expensive bills on both carriers. Is it possible to have both cellular networks active but have one taking all the traffic?
If the failover is to be done between two different cellular routers, you would need to implement a mechanism, such as VRRP for both devices to test their links to the outside and make a decision on which should be the “path” (master/backup)
If you want to do failover with dual SIM on each units, we also have mechanisms for testing and falling back (note however that you can only have one SIM card active at a time since there is only one cellular module inside such devices)