New here, came across this post via a google search for details on dual wan on the RT-AC68U. My internet failed midday Friday, called my ISP who informed me they'd only be able to get an engineer out the following Tuesday!
Unacceptable as I work from home. Off to Currys I go, picked up a 4G EE Osprey device.
It wasn't what I was after in terms of having a USB plugged into the router acting as backup, figuring I'll switch between the two as and when needed. It would have to do.
So, today I plugged it into the router USB port just to see out of interest as to what it would do. I was pretty surprised to see it recognised as a USB modem, clicked it into dual WAN mode, and wow, it just worked once settings updated. It was pretty straight forward really.
I unplugged my ISP wan connection, and everything just carried on working as normal. Very impressed!
I would leave it like this, but the only concern I have, is that it is on a 15Gb/m rolling contract and am worried that it might go over this. Its been on for 8 hours and is over 650Mb of usage, and that's during the quiet time when the kids are at school. So, I'm looking to set it into failover mode. I'm running Merlin which I installed 10 minutes after unboxing my router when I got it not long ago. (Wanted the extra functionality of DD-WRT which I'd used before on an old router) ... So, I'm hoping that failover will work once I work out the settings. The comments above are a bit worrying in that it won't work, but who knows, this is a rather old thread so maybe things have changed
Edit: FYI, my internet was back up and running when I got home at 7pm the Friday - doh!