I have been using Telus internet for over two years and I use my own router during the entire time with Telus. However, since late June or early July the bridging mode does not seem to work anymore. The third party router will disconnect from internet after 10 mins. A quick reboot or unplug the wire fix the issue for around 10 mins.
I am not the only one experiencing this issue as from online research other telus users on router forum experiencing similar problems.
For example this post:
I just want to find out if other Telus users here is experiencing this problem.
Never had that issue with mine though I did NOT bridge port 1 and left my router doing it's own thing. Has worked quite well. Now in your case, if for some reason bridge mode is not working, that should not cause your connection to drop. Is it just your router going down or is it everything connected to the T3200M? Do the lights on the T3200M change color or go off at any point you experience problems? Worst case scenario, you may want to try a reset on the gateway and set things back up from scratch. Only thing left after that could be a hardware problem with either device.
I have been using bridge mode for a few years now and never had any problem until very recently. Then it turned out to be my Asus Router firmware update that did it and a full reset of that and entering the parameters again fixed everything. Not sure which router you are using but it could be from your router's side. Did it get a new firmware? Worth looking into.