I recently experienced a total network failure of my Xfinity XB8 Modem. I have numerous wired and wireless SONOS devices connected that started dropping out and overall slow network performance.

Xfinity replaced the XB8 modem, and the issues continued with SONOS. I then turned off all SONOS equipment and the network issues were resolved. I verified the configuration of the three TP-LINK Managed Ethernet switches and confirmed that everything was correct (RST Settings).

I then turned on all of the computers, NAS and printers and the network remained stable. I then turned on each of the wired SONOS devices and the network was stable until I turned on the PORT and the PLAYBAR and the network became unstable and unusable. Each SONOS device is plugged into a TP-LINK managed switch.

I then ran Wireshark and noticed an excessive number of “LINK LOCAL ADDRESS” broadcast coming from the XB8 Modem with the Source Address starting with fe80:: - ICMP V6. I then turned off both SONOS devices and the network returned back to normal. NOTE: While this broadcast was occurring the SONOS app was very slow to respond, network printing was generating errors and the browsers were slow,

I have been working on this all day and will do some more trouble shooting tomorrow so I can isolate the specific SONOS product that is causing the issue. I suspect it may be the PORT since it took a very long time to connect to the network. 

Has anyone else run into this?