Re: Bluetooth mesh - node with 2 elements - Not enough tailroom for TransMIC


laczenJMS
 

Hi Johan,

Thanks for the response. I couldn't find CONFIG_BT_MESH_TX_SEG_COUNT
as configuration option, but I tried changing
CONFIG_BT_MESH_TX_SEG_MSG_COUNT which defaults to 1. I changed it to
10 but I am still getting the Not enough tailroom message. I am using
both 16k and 32k nrf51822, at the moment I am testing with the 32k
version.

Kind regards,

Jehudi

2017-10-17 11:41 GMT+02:00 Johan Hedberg <johan.hedberg@intel.com>:

Hi Jehudi,

On Tue, Oct 17, 2017, Laczen JMS wrote:
I am trying to make a bluetooth mesh zephyr node with 2 elements.
After provisioning (which assigns 2 node adresses) meshctl ask for the
composition data. This fails with Not enough tailroom for TransMIC:

[bt] [DBG] dev_comp_data_get: (0x20001950) net_idx 0x0000 app_idx 0xfffe src 0x0
[bt] [ERR] bt_mesh_model_send: Not enough tailroom for TransMIC

What configuration option do I need to change (I am working on nrf51822) ?
I think you need to change CONFIG_BT_MESH_TX_SEG_COUNT. IIRC it defaults
to 3, and with your two elements you've created a composition data that
doesn't fit in three segments anymore. Increasing the SEG_COUNT to 4
will probably fix the issue. Note that this will also increase the
runtime memory consumption, so hopefully that doesn't go over your
limits (IIRC you had 16k?).

Johan

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