SonosNet (mesh) requires at least one wired unit. If there are no wired units you are using WiFi mode. A wired BRIDGE or BOOST puts the system in SonosNet mode. Any of the Sonos units can be a mesh node. BRIDGE and BOOST are nodes with the audio capability stripped out in order to keep costs down. Use them when the most practical Ethernet port does not need nearby audio or they can be used to improve SononNet coverage to a distant area. Any combination of wired and wireless is welcome. If you use managed network switches, make sure that the Sonos ports are set for STP, not RSTP.

Sonos support may not be as eager to condem the BRIDGE power supply as I am. My strategy has been, when a system is being weird, assume that the BRIDGE power supply is the bad guy until proven otherwise. This saves a lot of diagnostic time. There are many potential symptoms when the power supply goes south. Rebooting BRIDGE may seem to cure things for a while — at least long enough for you to pull out of the driveway. BRIDGE may not reboot after a firmware update. It’s link lights may be ON while nothing is connected. And, I’ve seen them take down the network. I have never taken the time to explore exactly how this is done because identifying and fixing the cause is so easy. This can be very frustrating because the power supply voltage may rise a little if it is rebooted and BRIDGE will work for a while. This will result in the diagnosis of “bad BRIDGE”. For the record, I have yet to encounter an actual BRIDGE failure, it has always been the power supply.

I also have seen a couple ZP100’s take down a wired or wireless network. This is easy to diagnoses — simply remove power. Note that, while this is on my “aware” list, it is not on my short list of troubleshooting things to do.