Sonos Bridge is Optional
Connecting at least one Sonos PLAY speaker directly using Ethernet cable creates the same dedicated Sonos Wireless Network.
A Sonos Wireless Network is also required to create your own home entertainment system if you wish to wirelessly connect the PLAYBAR to the SUB and rear speakers.
So, you have a choice of buying a Sonos Bridge if your speakers are no where near the home router.
Gallery: Sonos PLAY:1Sonos PLAY:1 Sonos Bridge