The TL;DR version of this is Chromecast and some other cast devices have been shutting down people’s internet by UDP flooding routers, a fix is supposed to be rolling out today.
TP-Link, a company I thought I’d reviewed before but evidently haven’t (boss has some Archer routers,) published a writeup on an issue plaguing many with Cast enabled devices – internet being slow or knocked out.
Under normal conditions a cast device will send out discovery packets every 20 seconds as sort of a “yo, I’m still here, anyone else? Wassup? Well then…” However if a device goes into sleep mode it may just wake up in a panic thinking it’s been asleep a couple of months and now needs to send a quarter million “yo, wassups?” all at once.
This issue will roll out gradually to the millions of cast enabled devices, maybe even slower than normal due to them knocking internet routers down.
The Google support document tends to indicate it may affect Chromecast, Home, Android, and third party appliances with any cast software built in. This means your TV you turn on once a week may not be getting the update it needs and may be knocking your internet down every time you turn it on and attempt to stream something.
While the WiFi manufacturers who found this are pushing some beta firmware, if you’re not into running beta just power off all the Chromecast stuff, power it back on, and hope it updates. If your internet goes out, reboot the router.
While this is a Google issue, and a pretty annoying one, it’s interesting to note that you can knock out name brand wifi without trying hard.[xda]