RE: mesh unreliable and reliable

jowei — Fri, 13 Jul 2018 07:38:32 GMT

Hi Rick

It's helpful to me, thanks for the answer.

Joseph

RE: mesh unreliable and reliable

Jui-Chou (Rick) Chung — Fri, 13 Jul 2018 06:46:09 GMT

Hello Joseph,

Basically, the time between every repeated-sending of "simple_on_off_client_set_unreliable" should be minimum advertising interval (20ms) plus a random time (0 ~ 10ms).

And for the acknowledge timeout, we can check the "access_reliable.h", line 70:

#define ACCESS_RELIABLE_TIMEOUT_MIN  (SEC_TO_US(30))

Please note that in the Bluetooth mesh specification p.96, mentioned that:

"The acknowledge message timeout should be set to a minimum of 30 seconds. The exact value is application specific."

For the number of retry, we may not able to set a specific number, but you may have interested to check the code in "access_reliable.c", line 240, which shows how the retry interval be calculated.

static uint32_t calculate_interval(const access_reliable_t * p_message)
{
    uint8_t ttl;
    /* The model handle should already been checked by the TX attempt. */
    NRF_MESH_ERROR_CHECK(access_model_publish_ttl_get(p_message->model_handle, &ttl));

    uint16_t length = access_utils_opcode_size_get(p_message->message.opcode) + p_message->message.length;

    uint32_t interval = (ttl * ACCESS_RELIABLE_HOP_PENALTY) + ACCESS_RELIABLE_INTERVAL_DEFAULT;
    if (NRF_MESH_UNSEG_PAYLOAD_SIZE_MAX < length)
    {
        interval += ((length + (NRF_MESH_SEG_SIZE - 1))/ NRF_MESH_SEG_SIZE) * ACCESS_RELIABLE_SEGMENT_COUNT_PENALTY;
    }
    return interval;
}

Hope the upon information can do help 🙂