wireless network scanner or tool?

  • 27 November 2008
  • 19 replies
  • 10594 views

Userlevel 2
Hi,
apologies if this has been asked before, but I'm having all sorts of interference with my SONOS wireless zones at the moment to the point the system is unusable.

The reason looking at the details of the Sonos network on a ZP is poor signal quality.

I know this is being caused by too many other types of wireless device in my home such as:

5 DECT phones
2 wireless Cameras
Wireless broadband router (B/G)
2 Baby Listeners

+ 7 zoneplayers and 3 controllers.

My question is - Does anybody know of a tool that can analyze / monitor channel usages/information in the standard 2.4Ghz spectrum. Either hardware or Software based.

If I could find a tool, have it monitor whilst turning devices on and off I'm hoping to get a better idea of what channel each device is trying to use. Some of the devices are configurable, so I can then move them to channels with less chatter.

Thanks all.

Nick

19 replies

You can use netstumbler to monitor wireless computer networks. To see what your cameras etc are using, you need dedicated hardware that's expensive. Luckily, Sonos does a bit of diagnostic itself.

You could try the following:
Access the Sonos diagnostic here:
http://192.168.0.20:1400/support/review
Where 192.168.0.20 needs to be the IP address of one of your zoneplayers.

Go to the "Network matrix". This will list a grid of all connections your players can make amongst each other. Each player needs at least one connection above 20.
Now switch your Sonos channel. Refresh the network matrix. You are trying to get at least one connection per device above 20.

If a connection is consistently bad, go through your other electronic gear, switching one off at a time and see when it gets better. The Noise Floor also is an indication where noise is high (-100 is good, -80 is bad).

If you can't work it out, contact support, they use this data constantly.
The other component of signal quality is "OFDM Weak signal level". Five is best zero usually implies impossible. Both Signal to Noise and OFDM Weak signal level can bounce around a bit -- depending on which devices were transmitting at the instant the diagnostic was taken (the diagnostic is a static snapshot).

DECT phones are not usually a problem, cameras and baby monitors can be very bad neighbors. The camera and baby monitor documentation will hopefully give the possible operating frequencies. You'll need to write down a matrix of possible frequencies and make sure that the cameras and monitors do not overlap with each other or SONOS or WiFi. While we usually recommend that SONOS and WiFi do not share the same channel, you may need to make that assignment in this particular case. WiFi and SONOS can usually share the same channel without major issues. Note that these devices do not use a single frequency, they use a range of frequencies for each "channel". One must make sure that the ranges do not overlap.

Based on a similar situation that I solved, try setting one camera to the lowest possible channel, the other to the highest, SONOS and WiFi to channel 6, and initially keep the baby monitors off. If the system is stable, introduce the baby monitors one by one and try to find a channel that does not break anything else.

Read through the manuals, if you are lucky the cameras or monitors may be able to use the 5.8GHz band.

As you have noticed by now there is much more information in the diagnostics, than we have hinted here. Since SONOS does not document the diagnostics we don't know what everything means, but you can send a diagnostic to SONOS (from a desktop controller), note the confirmation number, then follow up with an email referencing that number. As you take the diagnostic, make sure that the handheld controllers are awake.
Userlevel 2
A call/chat to Support is usually the quickest way to go through the diagnostic as there is also:

/proc/ath_rincon/fullstatus

code:
contents of /proc/ath_rincon/fullstatus
Debug info for INFRA mode at 12717051

Operating on channel 2412
RF Chains: 3
Noise Floor: -91 dBm (chain 0 ctl)
Noise Floor: -94 dBm (chain 1 ctl)
Noise Floor: -89 dBm (chain 2 ctl)
PHY errors since last reading/reset: 21
OFDM Weak signal level: 5


This is where you can see if there are gaps in signal getting from one ZP to another.

As for sniffing hardware/software, I've used the original Wi-Spy from http://www.metageek.net/ with some luck. Netstumbler is decent at seeing what else is around you and it's free, so that may be a better start.

The best start is the call to Support as they can, at the very least, point you in the right direction.

-Jason
Userlevel 2
Thanks to all three of you some really useful stuff, I'll take a look at this in some detail over the next couple of days I'll let you know how I got on.

Thanks again,

Nick
Userlevel 2
Ditch the wireless cameras if they are in the 2.4ghz range. I'm a wireless engineer and have the Cisco (formerly Cognio) Spectrum Expert tool and have ran scans on my setup with a Linksys wireless camera. The camera will eat 100% duty cycles not allowing anything else to talk on the frequency.

Baby scanners might not be bad, they are typically like a cordless phone and don't eat all the cycles, usually closer to half.
Userlevel 2
Hi, I've also been having such bad interference over past couple of weeks that system is almost unusable. Based on feedback from one Sonos support person, I ditched my 2.4 phone and replaced it with a 5.8. Problem went away for a bit and then came back worse.

Next support person told me to ditch the 5.8 phone, because those can supposedly be a problem too! (He also said I should start ripping at a lower format, because the dropouts were worse with lossless files than with MP3s - anyone else experienced this?) So I did that, and then guess what - problem back, worse than ever. (And I now have analog phone, so can't possibly be that.)

I'm really frustrated at this point, but I'm going to try those various wireless detection tools and see if they help. I'm in an apartment bldg, maybe interference is leaking through the wall from someone else's baby monitor. Either way, I've stopped raving about Sonos and I'm starting to complain about it...
Userlevel 2
Also, sorry for the dumb question, but how do I figure out the IP addresses of my zone players?
Also, sorry for the dumb question, but how do I figure out the IP addresses of my zone players?

On the Desktop Controller, choose "About Sonos Desktop Controller" from the Help menu.
Badge +2
I have used Wireshark to capture packets from the wire for troubleshooting. It is available at www.wireshark.org

I am also experiencing some communication problems. Using NetStumbler you should be able to loacate other wireless networks in the area. I can see at least six of my neighbors wireless connections. All of us are using the AT&T Uverse system which is using a 2-Wire Gateway

Next support person told me to ditch the 5.8 phone, because those can supposedly be a problem too! (He also said I should start ripping at a lower format, because the dropouts were worse with lossless files than with MP3s - anyone else experienced this?) So I did that, and then guess what - problem back, worse than ever. (And I now have analog phone, so can't possibly be that.)


I would think the switch to a 5.8 Ghz Phone would have been a good thing. Unfortunately, you would need professional equipment to detect anything other than wireless networks that are interfering.

How is your living situation? Big city apartment blocks are notorious for wireless congestion. Really bad are wireless security cameras and A/V transmitters, but phones and baby monitors can also be a problem. If your neighbors have these, they will also cause problems with Sonos. Buzz would now say "keep a log, you might find a pattern", you could maybe establish which neighbour is causing the trouble.

Sonos support won't give you the following tip, because it is not officially supported. You might try homeplug powerline adapters to connect the Zoneplayers. They have solved problems for others.
http://www.pcworld.com/article/138091/powerline_adapters_home_networking_without_rewiring.html
http://www.google.com/products?q=homeplug+ethernet
Userlevel 2
Thanks for both these responses - will continue investigating (and also look into whether maybe the new Z90 player might solve problem).

Meanwhile, netstumbler and wireshark both seem to be windows-only. Anyone know of a mac-compatible version?
Userlevel 2
Thanks Avee, that's really helpful, I will look into the powerline option. I am in a co-op, not a big building but I guess could be part of the problem. Just imagining what the response would be if I asked all my neighbors to please ditch their baby monitors and 2.4 phones ;)

Also, wondering if anyone else has ever been told by Sonos support that, if you're having interference problems, you should try streaming smaller files? I'm a bit of a stereo geek, so I hate to give up on the lossless, but I do see them problem diminish (though not go away entirely) if I try playing smaller MP3s...
Userlevel 2

You could try the following:
Access the Sonos diagnostic here:
http://192.168.0.20:1400/support/review
Where 192.168.0.20 needs to be the IP address of one of your zoneplayers.



Thanks Avee!!!

Are there any other gems of info from port 1400?

When I had a ticket open with Sonos for my recent networking issues, I learned about the support/submit page and wished for an XML parser to make use of that info better.

But the links at support/review are great. I'm a Linux engineer and walk around the procfs and sysfs parts often in my job.

Love this info. I wish I knew about it from Sonos when I was trying to go through the steps of figuring out what could have been causing 2.4 Ghz interference...

Cheers!
--jans
Userlevel 2

The Noise Floor also is an indication where noise is high (-100 is good, -80 is bad).


Hi Avee again,

Sorry to be a pain. But the lower the -xxx value of the Noise Floor the more that that ZP is seeing noise?

I.e. I have most of mine are in the -90s so I'm assuming that that's "good".

My LR ZP sees a -88.

Also, for 2 of my ZPs only a single number is listed in the Noise Floor, but 2 ZPs have 3 numbers there. Does more numbers mean that there are more devices that that a given ZP are seeing?

E.g.:

Living Room
Noise Floor: -90, -93, -88

Master Bedroom
Noise Floor: -95

So does that mean that my LR ZP is seeing 3 sources of noise interference and my MB only 1 source???

Is my interpetation even close?

Thanks!
--jans
-80 is good enough, -90 is better.

I don't know either what the multiple values mean 😞
jsteve,

The ZP120 and ZP90 give the three noise floor numbers.

Keep in mind that the status reports are a static snapshot. If you dig around, you can find a history. You'll also find /proc/ath_rincon/phyerr interesting. This is a histogram of errors. It is unlikely you'll never observe zero errors. As you approach and cross 50k, performance will degrade significantly.

If you wish to explore the robustness of the system while listening to music, unplug the network cable from the music . Initially, you'll think that you pulled the wrong cable. Even more interesting, transfer the cable to another ZonePlayer.
Userlevel 4
Badge +1
The diagnostic was working fine when I tried it yesterday, but today I get this message

Any idea why?


Power cycle that ZonePlayer and try again, or use the IP address from a different ZonePlayer.
Badge
Power cycle that ZonePlayer and try again, or use the IP address from a different ZonePlayer.
I did try the IP addresses from different Zoneplayers with no luck, however after power cycling a single ZonePlayer, I can now see them all again.

Thanks for the advice Gordon.

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