E400 2.4 GHz clients lose wireless connection randomly


I have an E400 with one SSID transmitting on 2.4. My problem is that devices (wireless clients) lose wifi connection at random intervals. They are only three but when one of them demands traffic (like video streaming) it loses connection, stops passing traffic for some seconds and reconnects automatically while the others experience delay problems or also disconnects for some seconds. 
I am running pings continuously to the default gateway, to a public ip and to the clients, and I see that the pings are stable and with standard delay (i.e. 1ms to the default gateway or 5ms to ther clients) but when the problem appears and before the client which demands traffic disconnects, the pings become unstable with intervals of very big and random delays (from 1ms, 60ms, 200ms, 900ms) until the connection drops and affecting the connection to the other wireless clients. While none of the devices demand bursts of traffic, the pings are stable with minimum delays. This happens every 5 minutes or less and rebooting the AP makes no difference, it re-conects to 2.4 and works for a while and then repeating this issue. There is no problem with the internet connection because I replaced the AP and didn't experience any problem with the devices.
The wireless channel I am using is the one with less noise level and tried with different channels with the same behaviour.

Is a problem of configuration?
Just in case I am attaching the Tech Support file  
Thanks in advance for help!

Hey Frama, I think I've experienced what you're going through. Here's a few things to try..

1. Make sure you've updated to latest stable release which is

Try the following settings one by one until you find something that helps. If it doesn't fix the issue, set it back the way it was and go onto the next setting:

2. Under radio settings, try disabling 'airtime fairness'

3. Under radio settings, set Canidate channels to 'specific' and then using the WiFi anaylizer to find a clean channel, set a specific channel

4. Under radio settings, try to disabling 'Auto RF'

5. Under radio settings, try to disable Interference Avoidence

6. Under the WLAN settings, try setting 'band steering' to disabled

7. Under the WLAN settings, disable both fast roaming standards and 802.11w state (I think these are disabled by default)

Try this and let us know what happens!

I have the same problem. What will be the cause and solution?

I have the same problem. Is the problem solved?

Are you on firmware version or an older version?

All of my APs are using r6. But i do not config my Ap like your guilde above yet.

Hi nhuphuc,

Can you please share the techsupport file of AP. You can download the file from following location 

Operations --> System --> Download Tech Support

If you are not able to upload the techsupport fle.  Please share it to my email id     ashok.kumar@cambiumnetworks.com

Hi Ashok!

I have sent you a mail attached with my tech support file. Please check email and let me know is there any miss configtion on my system. Thank you so much.

Hi  Nhuphuc, 

We need AP's techsupport file.The file that you shared was CnMaestro's one. Can you share AP's tech support file (attached snap shot for reference)

If you don't have the access to AP , then download the techsupport of AP using NOC from following location (attached snap shot for reference)

1) Select The Device in Dash board

2) Click Tools Tab 

3) Download techsupport of an AP

Hi Ashok!

Sorry for my misunderstanding. I have resend email for you. Thank you.

Thanks Nuphuc for sharing AP's tech dump file. Can you please answer my following queries /information required 

  • How AP’s are located
  • Distance between clients to AP’s
  • How frequently you are seeing this issue

Is it possible to give us the remote access of your network ? If yes can you please provide access to CnMaestro and AP's If it is not possible provide your complete network diagram configuration details.


Any solution?

it seems I have same issue

alguma solução?

Hi nhuphuk,

                    I have also come across such situation where clients complains about random disconnection and reconnection. But in later stages, I found the issue was basically arised from anti-virus. After install new patches by anti-virus central console by client ,the issue was automatically dissapeared. If possible you can check the issue one by one as you have mentioned you are having only three machines. I may not be 100% correct in your case but it is my experience which has same scenario as you are. 

Hi nhuphuk, in very rare cases this kind of issue arises from bug in the firmware of the access point device.


How far are your clients from the AP?

If you are sitting in front of AP that is set on max Tx power, clients may disconnect because the AP is too loud. In that case decrease Tx power settings. I had many examples of such case with customers. 

That could be one option ofcourse.

Could you guys mention which kind of clients are disconnecting? Smartphones, tablets, laptops with integrated wifi cards, wifi USB sticks, anything else? 

We've found that the following settings results in a more stable E400 experience with less disconnects:

Under Configure -> Radio:
Channel: Automatic
Channel Width: 20MHz for 2.4, and 80MHz for 5GHz
Airtime Fairness: Disabled
Mode: gn for 2.4, and nac for 5GHz
Auto Channel Select: On-Startup (but I'm curious to experiment with the 'No Clients' and 'Scheduled' options)
Off Channel Scan: Disable OCS
Auto RF: Disable Auto RF
Interference Avoidance: Disable Interference Avoidence
Enhanced Roaming Tab: Enable, threshhold set to 10dB SnR (for both 2.4 and 5ghz)
All other settings are DEFAULT
Under the WLAN/SSID:
Drop Multicast Traffic: Enabled
UAPSD: Disabled
QBSS: Disabled
Band Steering: Normal
Fast Roaming: ALL DISABLED
All other settings are DEFAULT

Thanks Eric for your update. I am apply the same in one of the AP which shows similar behaviour for last couple of days after installation. Let's see the result. Hope ,it would also work in my case also.

May be due to Interference or congestion and some times not getting connected to resources

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