@Kevin_Z Yes i did. Other router works normally when the ISP fails and gets back to normal.

@Kevin_Z I don't use QoS as it's uncompatible with Nat Boost and i've tested it.

@Kevin_Z Powercyclying the router won't solve this issue unfortunately. The only way is doing as i said before. It took a long time for me to find this "solution".

I can see a strange behaviour with my C7. Everytime my ISP fails access for some reason, i got my conection speed reduced. I have now a 300/300 Mbps connection and when my ISP fails access, after...