Hi, I have been playing Super Smash Bros. online on the Wii U and 3DS, and on both consoles every two or three matches I will be suddenly disconnected (ie. the screen will freeze and the loading icon will appear for 15-20 seconds,and when play resumes my opponent will have been replaced with a low-level computer; I don't get an error code of any kind). The weird thing is, when playing I have absolutely no lag at all so it's not a problem with my internet speed. I've also never had this issue when I've taken my 3DS to friends' houses,so it seems to be a problem with the way my Nintendo consoles interact with my router. Also my other devices (laptops etc) don't disconnect when this happens and I have no problem playing PC games online.
The things I have tried include:
Using a LAN adapter and ethernet cable
Putting my consoles in the DMZ
Setting a static IP and forwarding the appropriate ports
Setting my router channel to 1, 6 and 11
Setting my DNS to Google's public servers (8.8.8.8)
Disconnecting from my wireless extender, in case that was causing interference
Turning my router's firewall off completely
Enabling uPnP
All of the above at once
I would be hugely grateful if anyone can think of anything else I could try, thanks!