questions about mesh message publication

[William.wei]

hi support team,

i have customer is developping mesh.

customer is trying to sniffer the message when i pressed the buttoon on demo mesh_light.

i have two questions on mesh.

 i set publication retransmission time for 0 in andriod mesh app, and here is the sniffer log:

my question is

1.why mac address is changing everytime device send the message after i pressed the button, is there  any document about this?

2.how to set the default trasmission（seems it is 3 internally） , if customer want to set this to 4 or 5

Regards,

William.

[Edvin]

Hello William,

The address is changing for privacy reasons. If you, however, for debugging purposes, want to keep using the same address, you can set CONFIG_BT_MESH_DEBUG_USE_ID_ADDR=y in prj.conf. This is not recommended for production. From NCS\zephyr\subsys\bluetooth\mesh\Kconfig:

config BT_MESH_DEBUG_USE_ID_ADDR    
    bool "Use identity address for all advertising"    
    help    
      This option forces the usage of the local identity address for    
      all advertising. This can be a help for debugging (analyzing    
      traces), however it should never be enabled for a production    
      build as it compromises the privacy of the device.

2.how to set the default trasmission（seems it is 3 internally） , if customer want to set this to 4 or 5

There are two parameters for this. One for relayed messages (messages that are picked up, and retransmitted out to the network), and one for when you are the originator of the message.

The relay count can be set using CONFIG_BT_MESH_RELAY_RETRANSMIT_COUNT

The transmit count can be set using CONFIG_BT_MESH_NETWORK_TRANSMIT_COUNT

Best regards,

Edvin

[William.wei]

Edvin said:

The relay count can be set using CONFIG_BT_MESH_RELAY_RETRANSMIT_COUNT

The transmit count can be set using CONFIG_BT_MESH_NETWORK_TRANSMIT_COUNT

no, it is not this parameter, i have set them to 0 as below:

and here is the log from terminal:

[00:03:45.292,144] [0m<dbg> bt_mesh_access: mod_publish: timestamp: 225292[0m

[00:03:45.350,677] [0m<dbg> bt_mesh_access: publish_sent: err 0, time 225350[0m

[00:03:45.350,708] [0m<dbg> bt_mesh_access: next_period: Publishing took 58ms[0m

static const struct bt_mesh_send_cb pub_sent_cb = {

    .start = publish_start,

    .end = publish_sent,

};

so everytime button pressed, the time i from publish_start to publish_sent callback  tooks 58ms and send the channel37,38,39 for three times internally.

how can we change it?

Regards,

William.

[Edvin]

William.wei said:

so everytime button pressed, the time i from publish_start to publish_sent callback  tooks 58ms and send the channel37,38,39 for three times internally.

Do you mean that it sends one time on channel 37, one time on channel 38 and one time on channel 39, or three times on each?

And what do you want to change it to?

[William.wei]

hi Edvin，

i mean in it costs 58ms to send packet in 37,38,39 then 37,38,39,then 37,38,39:

Regards,

WIlliam.

[Edvin]

Edvin said:

The relay count can be set using CONFIG_BT_MESH_RELAY_RETRANSMIT_COUNT

The transmit count can be set using CONFIG_BT_MESH_NETWORK_TRANSMIT_COUNT

Have you tried setting these?

[William.wei]

hi Edvin,

if those are set, it would be as below:

what i ask is the time cost inside  the first transmit.

Regards,

William.