Many users reported experiencing Wi-Fi connectivity problems after setting up a Google Chromecast or Home speaker.
Google’s Chromecast and Home devices are growing in popularity in many households, but it seems that they are also interfering with Wi-Fi signal in a range of cases.
The bug itself is not a router problem, rather an issue with the ‘Cast’ feature itself.
The issue was first brought up on Google Product Forums in relation to the TP-Link Archer 1200 router, according to The Register.
TP-Link engineers explained that the Cast feature sends multicast DNS (MDNS) packets to discover and keep a live connection with Google products.
MDNS seems to be the issue
MDNS resolves the hostnames or assigned network names of devices to IP addresses, and is widely used on local networks without a DNS server. According to XDA-Developers, packets are usually sent every 20 seconds or so.
The problem seems to be that the Google devices will broadcast a large amount of these packets at rapid speed in a short space of time. This happens when the Google device is awoken from its ‘sleep’ state and, the longer it is in sleep mode, the larger the quantity of MDNS packets sent will be once it ‘wakes up’.
MDNS uses User Datagram Protocol (UDG) to send information packets. UDP has no congestion control features, so a device sending multiple UDP packets in a short burst can grind things to a standstill pretty swiftly.
If this issue isn’t remedied, the router’s memory could be filled up completely by the MDNS packets, leaving users with no choice but to reboot in order to restore the internet connection.
Router manufacturers such as TP-Link, Linksys and Netgear have acknowledged the problem and issued firmware updates, and these updates will act as mitigation until a patch for Cast is issued by Google itself.
A company spokesperson told 9to5Google that its team is “working quickly to share a solution”.
Some of the routers are seeing signal dropping altogether, while others become inoperable for short periods of time.
Updated, 10.30am, 18 January 2018: Google has stated that it is aware of the problem with the Cast software and it is rolling out a fix today via a Google Play Services update.
In the meantime, users should try rebooting their Android phone, and check that their Wi-Fi router is running the most recent firmware version.