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bcn_timout occurs very often

For the last few months, we have been struggling with the following error occurring far more often than expected:
bcn_timout,ap_probe_send_start followed by ap_probe_send over, rest wifi status to disassoc, and then a full wifi reconnect.

Here are some of the tests we have done, all with ESP-12F modules (ESP-8266)

From these results, we don't believe the cause of these disconnects is our production firmware, but is instead some interaction between mgos and the hardware.

Additionally, we have used wireshark to capture the wifi traffic. Those results can be shared as well if desired.

At this point, we need to find a solution to this disconnect issue, as having devices disconnecting from wifi every 30 seconds, every 10 minutes, or in the rare best cases, every hour, is not acceptable for a commercial product.

Any and all help is appreciated, thanks!


  • This bcn_timout should be "beacon timeout".
    I get the same problem.
    In lua firmware "wifi" module, it says "Any function or task that takes longer than 15ms (milliseconds) may cause the WiFi subsystem to crash."

    So, if mongoose-os has some task take time for 15ms or higher, then it loses the router signal.

  • andrew_peandrew_pe United States

    Yup, although I think there might be some other issue at play in this situation. The device is sending a TON of Null frames and many probe requests that the AP isn't responding too. It seems like an excessive number to me, while on Arduino there are none and even on mgos connected to a different AP, there are far far fewer.

    I have lots of data like this if it can be of use. I wonder if it's an SDK problem, but my post on the Espressif forum hasn't been published yet.

  • Espressif FAQ, it says that reason is the bad quality of WIFI.

    Increase the value of 'beacon interval' from 100 to 200, disconnection is improved, but it still existed. Perhaps I should change it to 500.
    Some problem is in ESP8266, but ESP32 is the better choice.

  • jnugenjnugen Cincinnati, Ohio, United States

    andrew_pe, were you ever able to resolve this problem? I'm having it too.

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