SM deregistered - INA confirmation not received by AP


Could anyone help me with this issiue? Link won't connect although it has good RSSI and SNR.

Thank you.

1 Like

I’m not sure if this will help or not, but this troubleshooting guide might help. :slight_smile:

Thank you for trying.

I got this info about all errors, but I have one that is not in the table :) 

Dec 23 10:24:33 XXXX kernel: [596657.750000] SM disassociated from AP[00:04:56:XXXXX] F=5835 11naht20. Reason: 52 (INAC MISS TIMEOUT)

Hi Anze,

What FW version is the issue observed with?

Thank you.


I am curently investigating a problem with Cambium Support ticket #203514. I had 4.4.3, now running 3.5.6 and testing what is the problem.
It looks like it could be very high interefences, but not yet sure. Will do more investigating tomorrow.

If it is interferences, it is interesting because SNR is really good and that doesn't make sense right away. Reflected to PTP820, I know there would be counters and MSE would be bad - as MSE is not the same as SNR.

Will let you know more tomorrow for sure. I would also appriciate if Cambium could update the error table from this post:

Thank you

To let you know what we have done with Cambium Support.

The problem are very high interferences. We tried different channels and downgraded  to 3.5.6. Now it is working smoothly with MCS limited to 10.

This is just my personal opinion: I got a feeling that 4.4.3 is much more affected by interferences than 3.5.6 - have not yet confirmed that.

Why was there SNR 30dBm and link still not working? I think because the interfences are very high just on one site (AP's side) and SM can see AP very well, but AP can't receive SM's packets with good SNR - but we don't have that information anywhere in GUI. We have to run spectrum analyzer to assume that.

Kind regards


Hi AnzeZ,

SNR is not reflecting actual interference level. It show signal against Noise Floor. Unfortunately technology used in ePMP is not able to measure CINR(Signal-to-Interference plus Noise Ratio) in a real time so you have to use Spectrum Analyzer to see if there is any interference.


@Dmitry Moiseev wrote:

so you have to use Spectrum Analyzer to see if there is any interference.

But, we can't without driving to the customer's house.
We need to be able to tell the SM to run the SA for a certain time (let's say 5 or 10 minutes) and then to reconnect to the AP and to display the results.

- accesses the SM
- changes modes it to SA mode
- does the SA for a certain time frame
- downloads the results
- then resets the SM to SM mode
- and when it reconnects --- uploads the results to the ISP.