MESH v5.0.0 chat_model "Out of segment buffers"

RE: MESH v5.0.0 chat_model "Out of segment buffers"

Hieu — Sun, 21 May 2023 21:24:49 GMT

Hi Jejpi23,

My sincerest apology for the long waiting time.

As you have noted, the buffer is filled. However, it cannot be emptied at will by the application, as it is entirely controlled by the mesh stack. The rate data is "consumed" from this buffer is also controlled by the mesh stack. Therefore, our only approach to this is to reduce the rate the data is added to this buffer.

Just like you have observed, one factor is how often messages are being sent.

Another factor is that, how many times each segment is resent.

As recommended by the Mesh Profile Spec v1.0.1 (applicable to nRF Connect SDK v2.1.2), section 3.5.3.3, each segment is sent multiple times. The number of times is configurable by CONFIG_BT_MESH_TX_SEG_RETRANS_COUNT. In my tests, reducing this to 2 has fixed the issue.

On the other hand, I would like to recommend you reevaluate the strategy to send sensor data via human readable mesh chat messages. Like we have seen, segmented messages are quite costly to the mesh stack. It is actually quite costly to the network's throughput and the devices' power consumption as well.
All of those are often scarce resources that needed saving.

The Sensor Models are created for the purpose of communicating sensor readings. Perhaps you could give those a try instead?
You probably already know it, but here are the links to samples that use the Sensor Models:
Bluetooth: Mesh sensor — nRF Connect SDK 2.1.2 documentation (nordicsemi.com)
Bluetooth: Mesh sensor observer — nRF Connect SDK 2.1.2 documentation (nordicsemi.com)

By the way, I don't really understand the motivation behind the implementation in the my_enemy function of your code. Having said that, I think it is just some test code, so it is not very important.

Once again, I am very sorry for the very long wait.

Best regards,

Hieu

RE: MESH v5.0.0 chat_model "Out of segment buffers"

Jejpi23 — Fri, 05 May 2023 14:00:15 GMT

v3.12.0 - nrf Connect
v1.2.4 - Toolchain
v2.1.2 - nrf Connect SDK

RE: MESH v5.0.0 chat_model "Out of segment buffers"

Hieu — Fri, 05 May 2023 13:56:31 GMT

No problem. Please remember to tell me the version of NCS you are using.

RE: MESH v5.0.0 chat_model "Out of segment buffers"

Jejpi23 — Fri, 05 May 2023 13:24:06 GMT

Yes, sorry my mistake.

RE: MESH v5.0.0 chat_model "Out of segment buffers"

Hieu — Fri, 05 May 2023 13:21:46 GMT

Hi Jejpi23,

You are using the nRF Connect SDK (NCS), right? The title says Mesh v5.0.0 and threw me off.

I am out of office for the next three working days, but I will attempt to reproduce your issue and look into it when I return. What version of NCS are you using?

Hieu

RE: MESH v5.0.0 chat_model "Out of segment buffers"

Jejpi23 — Fri, 05 May 2023 09:25:13 GMT

Update

When i change the k_timer_start second time value the error appears either sonner ( if the value is lower) or way later ( value = 2000, ater 3000+ records i saw the error).