A bug in the software used by Google Cast devices such as Chromecast and Home can slow down or crash WiFi networks.
The problem — initially believed to be isolated to a particular router model made by TP-Link — appears to affect models made by other manufacturers, including Asus, Linksys, Netgear and Synology.
The Cast feature on Google’s home devices is the culprit behind the WiFi problems, according to a post on the TP-Link website. Cast sends MDNS multicast discovery packets in order to discover and keep a live connection with Google products such as Home. These packets normally are sent in 20-second intervals.
However, after a device wakes up from sleep mode, it sometimes broadcasts a large amount of the packets — more than 100,000 on some occasions — at a very high speed in a short amount of time. The longer the device is asleep, the larger the packet burst will be.