BLE mesh - Removing node from network

[Rob Johnson]

Is there a method to remove a node from the network using the current bt mesh stack? I've looked through device_state_manager.c but it appears to me that there are only functions that would be used to add information rather than removing one.

My use case needs a way to remove a node so it can be added to another network, or just reset to a default state so that it can be used in a different context.

[Hung Bui]

Hi Rob,

To remove a node from the network, there is a command from the configuration client called: CONFIG_OPCODE_NODE_RESET. Calling config_client_node_reset() will send that opcode.

Unfortunately we haven't implement that on the server side. If you have a look at handle_node_reset() in the configuration server, you can see the TODO.

What you need to do is to implement some command to erase configuration and provisioning data in the function.

Note that this is not the way to force the node to be out of the network. It's upto the server to accept that command or not. To be able to force a node out of the network, a "network key refresh" is needed. But this is not implemented in our stack yet.

[Johnny wu]

Hi Hung,

Mesh SDK: nrf5_SDK_for_Mesh_v1.0.1_src

Sample code: light switch server

Now, I try to remove node from mesh network on server side by using button event trigger, For example,  long push button over 15s, the server node will clear the configuration information and reset network state, when button is pressed, it will trigger the event handler mesh_node_configuration_reset() , but it is ASSERT when handling net_state_reset().  

void mesh_node_configuration_reset(void)
{
    /* Clear all the state. */
    access_clear();
    dsm_clear();
    net_state_reset();

    /* System reset */
    const config_server_evt_t evt = {.type = CONFIG_SERVER_EVT_NODE_RESET};
    app_evt_send(&evt);
}

while commiting the net_state_reset(), it is successful, but I don't think that this action is correct, because the network state(IV index and sequence number) don't clear, It seem that the cause of bearer layer event flag is not set, right ? How to fix it?

Best regards.

[Hung Bui]

Could you tell what was the error number when the assert occurred ? 

[Johnny wu]

There is any error number return when the assert occured. The ERROR LOG as follow:

<t:          0>, main.c,  184, ----- BLE Mesh Light Switch Server Demo -----
<t:        324>, main.c,  105, Initializing and adding models
<t:    4958557>, main.c,  115, Successfully provisioned
<t:    5299612>, main.c,  166, button_event_handler:Button 13 pressed
<t:    5463683>, nrf_mesh_node_config.c,  118, MESH ASSERT at 0x00022A0C

But, I confirm that  the error occur at seqnum_block_allocate()-> flash_manager_entry_commit()->schedule_processing()->bearer_event_flag_set() in net_state.c, may be caused by m_processing_flag, so how to set this flag to do network state reset via button event,  but not bearer layer event.