Advanced Sonos Wireless Network Configuration Using Sonos BOOST

Have you seen the Group Coordinator discussions here?

https://en.community.sonos.com/controllers-software-228995/sonos-group-coordinator-question-6803946

Multiple unicast, at layer 3. Unfortunately the picture at L2 is not entirely clear from the matrix, since Direct Routing will try to short-circuit the STP topology between grouped (and paired/bonded) nodes. .
Is there a way to see exactly what paths SonosNet is using at any moment? And, even better, is there a way to see how much of the music traffic is unicast vs multicast? I am trying to work out what I need to change in order be able to play FLAC files in Party Mode. It is currently failing, presumably due to bandwidth restrictions somewhere on the 2.4GHz network. I am still a beginner with Sonos but hope to get up to speed soon.

Thank you @andrewlydon

Since I first published this post, I have upgraded all of my home networking gear to Ubiquiti Unifi. . Coincidence. So did I. But I don't have a wired house and went for the dumbed-down Ubiquity AmpliFy instead. At least most devices are now off the 2.4GHz network.

For a full write-up about Ubiquiti Unifi and Sonos best practices, please read here:
http://freetime.mikeconnelly.com/archives/6373 . Excellent articles. A big thank you for making it all so clear.

For my home network, three pairs of Sonos smart speakers seems to be the breaking point before I experience one or more speakers dropping out.. Exactly the same here. My back-of-envelope calculation shows that FLAC takes about twice the bandwidth of MP3. But that fact alone doesn't quite explain why we get drop outs, does it? Or maybe it does. I am still trying to get to the precice technical reason for the problem.

Multiple unicast, at layer 3. Unfortunately the picture at L2 is not entirely clear from the matrix, since Direct Routing will try to short-circuit the STP topology between grouped (and paired/bonded) nodes. .
Is there a way to see exactly what paths SonosNet is using at any moment? And, even better, is there a way to see how much of the music traffic is unicast vs multicast? I am trying to work out what I need to change in order be able to play FLAC files in Party Mode. It is currently failing, presumably due to bandwidth restrictions somewhere on the 2.4GHz network. I am still a beginner with Sonos but hope to get up to speed soon.
The STP topology can be determined from the Network Matrix at http://IP_of_player:1400/support/review. I don't believe there's anything user-accessible which displays the active 'short-cuts' in use by Direct Routing in a group situation. It might be possible to assemble the picture from the 'direct=X' information against each wireless tunnel in the individual STP pages (/usr/sbin/brctl showstp br0). A 'direct' parameter of 1 or 3 means that tunnel is a candidate for Direct Routing.

Since Sonos have access to the full diagnostic, and presumably will have written all kinds of tools to parse this into useful views of the system, you're probably better off consulting them.

@andrewlydon

FLAC and ALAC (Apple Lossless) compress PCM/WAV to between 33% (classical) to 70% (rock) of the original CD source. With some notable exceptions, most internet streams top out at 128kbps. So, VBR lossless tends to be 4-7x the bandwidth of a 128kbps CBR stream.

The way that Sonos engineers have explained it to me, if you use SonosNet (BOOST mode, not Standard WiFi), then both the control protocol and the music will be multicast. If you use Standard WiFi, then the control will be multicast but the music will be unicast. This leads to scaling issues quickly in Standard mode, not least because Standard mode is 2.4Ghz only (a software, not hardware limitation in the Sonos One). Which is why you should prefer BOOST mode if you have multiple Sonos speakers.

They caveated that even with BOOST mode exclusively using 3 BOOST devices, Party Mode--in my case, 16 Sonos Ones--may be susceptible to drop outs due to coordination issues where there is a significant amount of other non-Sonos multicast traffic.

In my case, I have 2 dozen Google Cast enabled devices (TVs, AVRs, STBs, soundbars, Google Homes, etc.) Even after (1) Google resolved the "mobile device wake up" multicast "storm" bug, (2) I properly configured STP and (3) I enabled IGMP snooping on my UniFi network, Sonos believes that there is still too much multicast traffic for Sonos to play a single lossless audio stream to more than 3 pairs of Sonos Ones. Similarly, I cannot play an internet radio station in Party Mode, though it does scale to more Sonos One speakers than lossless audio. (No, this doesn't make sense to me if the audio is supposedly multicast in BOOST mode).

Hopefully, we will get to the bottom of this issue soon.

Have you seen the Group Coordinator discussions here?

https://en.community.sonos.com/controllers-software-228995/sonos-group-coordinator-question-6803946

Yes, thank you. However, my topology is slightly different. I am using three Ethernet-connected BOOST devices to serve my Sonos speakers. None of my Sonos speakers are Ethernet-connected. However, I don't have RF issues given the BOOST devices. STP is properly configured across the three BOOST devices as confirmed by the network matrix.

@ratty. Thanks for the great tips earlier in this thread. I will study the available diagonistic info and get up to speed with the terminology and general idea of how it is supposed to work before getting a Sonos techician involved. I don't want to be a PITA if I can figure it out myself.

@MikeConnelly. Good idea about considering the nature of the sound coordination overhead. I agree with you that I would have expected a single sound source being delivered to every speaker (Party Mode) to be implemented as multicast. But what about any inter-node coordination effort? I will think about that. Wouldn't it be ironic if there is some technical reason why you cannot broadcast music on a *wireless* computer network. ?

I'm rather surprised at Sonos Support's comments about multicast. There's obviously an initial multicast discovery from the controller (SSDP) but control traffic is unicast, to the player in focus. One can sniff traffic from a Desktop Controller to confirm this. There'd be no logic in, say, multicasting volume commands destined for a single player. Even in a group context, adjusting the master volume sends a flurry of unicast packets, to each player.

As for stream data when grouped, I have measured traffic away from the group coordinator and it's most certainly multiple unicast. Indeed, to one room where there's a stereo pair there are two streams (one per channel), which is what I would expect. This is for a household in SonosNet mode.

Distribution at layer 2 is a bit more complex, since as noted a coordinator will try and use direct peer-to-peer connections if it can. This means that L2 traffic doesn't necessarily follow a path along the STP tree.

As for the 'coordination overhead' in a group this is presumably the exchange of timing information via SNTP which, if I recall, takes place at 1 second intervals. That may be multicast, but the traffic volume is tiny compared to the music streams. That said, non-Sonos traffic loading down SonosNet could potentially cause the loss of SNTP packets which might eventually trigger a sync failure. But putting heavy non-Sonos traffic onto SonosNet is bad practice anyway, as it could cause dropouts.

As for the 'coordination overhead' in a group this is presumably the exchange of timing information via SNTP which, if I recall, takes place at 1 second intervals. That may be multicast, but the traffic volume is tiny compared to the music streams.

I have been told by Sonos Support on multiple occasions that in stereo pair and grouping scenarios that wifi is necessary even when all players are ethernet cabled. I couldn't get more details, they insisted that i needed to do something about wireless interference which is not possible in an urban apartment building, andwhy everything is wired.

I wish we could get some clarity on situations like this.

I have been told by Sonos Support on multiple occasions that in stereo pair and grouping scenarios that wifi is necessary even when all players are ethernet cabled.
That's surely just their standard line that disabling the radio is not officially supported. Disabling the radio (and in some cases, hard-wiring) will clearly affect whether and how the system makes direct wireless connections in a bond/group. But if you're all-wired I don't see how it can make any difference.