sensor_server with LPN feature enabled only responds to sensor_client's descriptor get msg when it is in a friendship

[deno]

Hi,

My development setup:

SDK/SoftDevice: nrf5_SDK_for_Mesh_v5.0.0_src + nRF5_SDK_17.0.2_d674dde + s140nrf52720

HW: nRF52840 DK

I modified the sensor_server example (SDK\nrf5_SDK_for_Mesh_v5.0.0_src\examples\sensor\server) to enable and incorporate LPN feature support  with reference to the lpn example.

BEFORE establishing friendship with the sensor_client node (which is running SDK\nrf5_SDK_for_Mesh_v5.0.0_src\examples\sensor\client), the modified sensor_server (with LPN enabled) is able to send mocked sensor value to  sensor_client sucessfully. Received mocked sensor value displayed properly on RTT Viewer connected to sensor_client. However, the sensor_server does NOT respond to the sensor_client's descriptor get messages and cadence get/set messages (which are triggered by pressing Button 1, 2, 3,4 on sensor_client DK).

ONLY AFTER getting the sensor_server node (with LPN) to establish a friendship with the sensor_client (or another sensor_server node WITHOUT LPN feature enabled), the sensor_server is able to respond to the sensor_client's descriptor get message and cadence get/set messages sucessfully.

Questions: 

1) Why the sensor_server node (with LPN feature enabled) is not able to respond to sensor_client's descriptor get message and cadence get/set messages when it is NOT in LPN mode (i.e when it is not having any friend)? 
    Is this an expected behavior for node with LPN feature enabled?

2) For node with LPN feature enabled but NOT engaged in any friendship (or not initiating friend request), shouldn't it behave just like any other node without LPN?

Thanks in advance for your support! 

  

[Mttrinh]

Hi,

For it to behave as a normal node outside a friendship there is a #define MESH_FEATURE_LPN_ACT_AS_REGULAR_NODE_OUT_OF_FRIENDSHIP which controls this behavior. I think this will solve the issue you are seeing in your first question.

[Mttrinh]

Hi,

The specification doesn't mention anything specific regarding this, but according to the documentation from our infocenter a node with the LPN feature enabled can work as a normal node until establishing a friendship with a friend node(take a look at the LPN life cycle chart).

[deno]

Agree with you, that's why I expect a node with LPN enabled but without friend should work as a normal node (i.e. #define MESH_FEATURE_LPN_ACT_AS_REGULAR_NODE_OUT_OF_FRIENDSHIP shall default to 1). If that #define is 0, the behavior of LPN node without friend is kind of not clearly defined (at least not described in nRF SDK documentation).

[Mttrinh]

I have reported this internally. In the mean time you can change the define to 1 if you like it to behave like a normal node outside friendship.

[deno]

Noted and thanks for your support and advice.