DLE (data length extension) and max att_mtu function to application

[CFF.K]

Hi,

I used sdk 15.2.0 version, I refer to the ATT_MTU Throughput Example to modify the Nordic UART Service (NUS) Application example.

Now I have some questions:

1. How could I check my program is turn on/off DLE or ATT_MTU function?

2. How could I proof turn on 『DLE or ATT_MTU』throughput higher than turn off?

By the way, I try to sniffer packet, but I don't know what different. could you support more document and experiment result for me?

Because I don't know how to show this function for my customer now.

3. The attachment is the sniffer log in Wireshark. You see No. 1090 packet that is to sent 247-byte data. This packet is an individual 27-byte to sent., but I turn on DLE function. I think this wrong that I think the packet is 247-byte by the once sent. (By the way, this test I use Samsung Note5 sent to nrf52)

nrf52_DLE_test_Note5.pcapng

[Kenneth]

Hi,

Many of the examples you can find in the nRF5 SDK have the following line of code:

    err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
    APP_ERROR_CHECK(err_code);

You can then get information about the supported lengths in the callback handler:

/** @brief Function for handling events from the GATT library. */
void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
    if ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
    {
        m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
        NRF_LOG_INFO("Data len is set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
    }
    NRF_LOG_DEBUG("ATT MTU exchange completed. central 0x%x peripheral 0x%x",
                  p_gatt->att_mtu_desired_central,
                  p_gatt->att_mtu_desired_periph);
}

Kenneth

[CFF.K]

Hi Kenneth:

sorry, I really don't know which do you answer. I know you support code, but I don't know what relates with my question.

Maybe I'm not smart, If my question isn't clear, please tell me. Could you mark the number of the question when you answer?

[CFF.K]

Hi Kenneth:

Could you help me something to figure out these questions?