If in recent times your modem-router has given signs of instability, before replacing it, try disconnecting your Chromecast first!
The issue could be due to an unspecified defect either on Chromecast or Google Home. Most likely Google Home. The App that controls it. A TP-Link engineer has posted an explanation of the problem. It first popped out in questions around the last year’s October.
It is not a very serious malfunction. Nevertheless is equally capable of putting in difficulty many famous modems-routers. TP-Link, Synology, Asus, Linksys and Netgear in particular, among others.
Depending on your modem-router brand it could cause a temporary internet disconnection. Even a permanent unavailability of the network may occuor. Until a complete reset.
TP-Link and Linksys have already confirmed the issue on their devices. For other brands we’re still awaiting for a coming-out, the list of devices is growing day by day.
If you’re interested in more details about the technical side of the issue, and want to try a solution for it, read the following lines. In them I’ll give some technical explanations.
From what TP-Link engineers have gathered so far, the issue appears to be related to some recent releases of the Android OS and Google Apps. The issue originates from these devices’ “Cast” feature. It sends “MDNS” multicast discovery packets in order to keep a live connection with Google products such as Google Home.
The interval between each of these cast packets is normally about twenty seconds, some say two of them every twenty seconds.
Some technical details, and how to fix it
This problem occours when the device awakes from “sleep mode”, and could send more than 100,000 packets in a short amount of time. The longer your device is in “sleep mode”, the larger this packets burst will be.
Due to the flood of packets the router will shut down connections, either to the internet or to the connected devices.
Generally, you will need to perform a reboot of your modem-router to release the memory and temporarily solve this issue. Plus you have to disconnect your Chromecast.
You may also try disabling the “Cast” feature on your Android device to help mitigate the issue until an update is released to permanently fix it on the device itself.
If the problem resided on the Apps compatible with Chromecast, an App update might do the trick, but if it was inherent to the operating system, Android Oreo is surely affected, you might end up waiting for an OS update: it might take longer.