MX with 2 DIA Circuits + 4G

[BrandonMcGrew]

I don't think my company is unique in this design but I have a challenge around the USB 4G modems. Current WAN configuration is 2 x land based fiber DIA internet circuits (various carriers) and 1 x 4G Skyus DS modem(I have a warm spare environment as well). I think it is safe to say the usb modems are remarkably unreliable and Meraki is putting zero effort in to them now that they have the MG series. The problem in my company situation is I already have a contract with 2 DIA circuits(WAN1 and WAN2) and I see no good way to leverage the MG series as my cellular backup due to this fact. 

Has anyone else figure out a good solution for something like this with a requirement to have 2 x DIA AND a 4G/5G Backup. 

[Owen]

Put a router in front of the MX to terminate one of the DIA services + the 4G.

MX keeps one DIA service + a connection to the router in front.

[marrees]

You could have a second MX as a warm spare, with the 4G connected to that via an MG.

[BrandonMcGrew]

Thank you both. The router idea has crossed my mind but Im trying to avoid putting anything between my MX and my carrier. If I have too I will but trying to find other alts first. What about the following configuration. 

Primary WAN 1 --> Carrier #1 

Primary WAN 2 --> Carrier #2

Warm Spare WAN 1--> Carrier #1 

Warm Spare WAN 2--> MG with Cellular

In regards to this design Im concerned about the conditions to force the Warm Spare to take over. Ideally the Carrier 1 and 2 would go down which would mean the spare is only available to communicate with dashboard and would force failover. Any thoughts?

[ww · Accepted solution]

Yes that would work fine. Spare wont be active until primary wan1 and wan2 fail. 

Only thing you cant do is use a vip on wan2.