Google Cast devices cause Wi-Fi dropouts on various routers

Devices that support Google Cast may cause wireless access points to freeze temporarily. This would be because when waking up from sleep, Google apps send far too many packets over the local network to discover Cast-compatible devices.

It would be recent versions of the Android OS and Google apps that can cast, such as YouTube. Normally, an mdsn multicast discovery packet would be sent up the local network every 20 seconds to maintain the connection to a Cast device. However, according to a developer of TP-Link, in some cases, depending on how long the device has been asleep, more than 100,000 of these packets are transmitted in a short amount of time. The result is that the access point temporarily gives up the ghost and local network traffic comes to a standstill.

The issue was identified by user nonameleft1, who is posting on the Google product forum. He collected four forum topics, taken from Linksys, Netgear, TP-Link, and Synology forums, describing the same problem by users. The first reports of the issue were posted in October 2017.

The problems would in any case occur with the TP-Link Archer C1200, the Linksys WRT3200ACM and the WRT32X. Those devices have all received beta updates. The Synology RT1900 AC also suffers from this, but there is no update for that yet.

Users can temporarily resolve the issue by temporarily removing Cast-enabled devices, such as a Google Home, Chromecast, or a specific model of TV from the network. Google itself has not yet responded to the issue. An update to fix the issue on their side would make modem and router updates obsolete.