Why doesn't SonosNet appear on wi-fi detectors

  • 25 February 2012
  • 12 replies
  • 4011 views

Userlevel 2
I've used InSSIder to look at wireless signals near me and it only detects a SonosNet signal if the Sonos controller (CR100) is on.

When the controller goes to sleep the SonosNet signal disappears off InSSIDer despite music still being played.

Why doesn't InSSIDer pick up the SonosNet signal ?

Is there another wifi detector that would see it ?

Would something like Wi-Spy see it ?

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12 replies

dr.phibes,

When a wireless device, including the CR100 is sleeping, its wireless is OFF. While there are technologies that can detect passive RF receivers, this is beyond the scope of WiFi listeners or spectrum analyzers.
Userlevel 2
Thanks but if music is still playing on zoneplayers why doesn't inSSIDer show the Sonos wifi signal ?
dr.phibes,

But what if the player is wired? Only the control commands to and from a wireless controller need any significant wireless transmissions. Music would play from the wired connection. There are occasional, brief beacons, however, if the probe device quickly scans the band, it may miss the beacons.

The WiFi card based scanners hop from channel to channel very rapidly and could easily miss a not so active access point. Earlier today I was using an Android with a scanning program in a coffee shop and several access points would be missing for several minutes, show up on one scan, then go missing again for several minutes. These were public, open access points.

The scanner must walk a tight rope, balancing between quick response (short dwell time), risking a miss, or longer dwell times with less risk of a miss, but likely to bore the human with the waiting.

Even if the SONOS player is wirelessly playing music, it will attempt to fill its buffer. Once the end of a track is in the buffer, no additional music data will be fetched till near the end of the track when the player fetches data for the next track.

If you are scanning while the buffer is full, there is very little wireless activity and the scanner could easily miss the device.
Userlevel 4
Badge +7
Thanks but if music is still playing on zoneplayers why doesn't inSSIDer show the Sonos wifi signal ?

Mine shows up when it is buffering music from my NAS drive.
Userlevel 2
Thanks for the replies.

Looks like I'd better run my tests and inSSIDer again.

And what sort of wireless activity is taking place when all components are in 'sleep' mode ? Would I be right in saying that zoneplayers sit there in a listening state waiting for an instruction to play music but occasionally transmitting a pulse to other players and bridges to say "hello I'm here" to keep SonosNet intact, rather than a constant wifi signal being broadcast.
My experience is that inSSIDer on one Win box fails to see Sonos at all, whilst on another Sonos is detected only when the CR100 is awake. The 'base station' MAC displayed in inSSIDer is the Sonos unit associated with the controller ('AssociatedZP MAC') which seems logical.
Userlevel 2
Ran InSSIDer tonight and Sonos did not appear on it at all. The ZP100 was wireless with a ZoneBridge connected to the home network via ethernet.

Tried inSSIDer on a 2nd Win laptop and Sonos didn't appear on that either.

Also tried WirelessNetView and NetStumbler and they couldn't detect it.

SonosNet hides itself well.
Sonosnet shows up on my inSSider but is erratic. Just checked now and it popped up straight away even though I haven't used the Sonos at all today. I have a CR100 which is sleeping.
Badge +1
I would suspect that Sonos uses a non-standard wireless protocol so tools looking for a standard wifi signal won't find the Sonos one. So short of a spectrum analyzer is there any public domain program/app that can detect the Sonos wifi signal along with all the others that are causing interference?
It seems that enabling SonosNet connection from an Android helps expose the Sonos BSSIDs. However the SSID is not broadcast so it may still not be picked up by scanners.
Using Wifi Analyzer on my Android, I can see the SONOS units. (After enabling the SonosNet connection).