YellowSnow :
Faike :
https://internethelp.centurylink.com/internethelp/modem-c1100z-adv-qos.html
Follow the instructions but disable QOS instead.
I did this already but it was for the main router. The extender is a completely different layout than the the main one.
According to this thread your main router has a fake QOS set up so this might be why nothing is changing.
"bill001g said:
So far I can't find the manual for this router. From the little I can see like many routers this router only pretends to have QoS. All these routers work on the false assumption that you can control overloaded download traffic by controlling upload traffic.
You can place certain of your internal ip into groups and mark then high low etc.
So if you get a overload condition in your upload it will send high value traffic first. Generally this only works for people who are uploading a lot of data to other users.
Some more advanced routers let you put ip addresses into groups and then place limits on how much traffic they can download. This also only partially works. The key problem is that ISP is deciding which traffic to send and which to discard. Does you little good if they decide to drop your important traffic and send you the other traffic which you then drop trying to make room for the good traffic. You dropping the other traffic does not magically get the data back the ISP already threw away. This only reason this method partially works is dropping traffic causes errors for the app you do not like. This means while it is trying to recover from these errors you can get your important traffic though...until the errors are corrected and you have to drop more traffic to cause more errors.
I suspect you are wasting your time with the router you have"
You can try turning off QOS on your brother's PC as well or just simply ask him not to connect to the Wifi using his phone or something to help prevent spikes like this.