Questions about data packet loss when using openthread and udp socket

[hyman]

Hello,

        We use nrf52840 to develop a data transmission device .We use ncs-2.2.0 ,IDE is VS Code .

        We use openthread to build a network ，We created a socket and use udp6 to send data .we need to send on one device, other devices can receive it ,so we set the socket addr as a broadcast address .

#define CONFIG_NET_CONFIG_PEER_IPV6_ADDR "ff03::1"

        The program runs correct ,We use two boards to test data transmission .

        The test method is as follows :Computer A sends data to (nrf52840 device  A) through uart，when received data , (nrf52840 device  A)  will broadcast the data through openthread .  when (nrf52840 device  B)  received the data through openthread ,it then send the data to Computer B. Each packet we send is 39 bytes ,and We send a packet every 100ms .

        We have tested that the uart works correct ,Uart did not lose packets .Thread will lose packets , About one packet will be lost for every 100 packets sent .

        I want to know whether the packet loss rate is normal ? What should I do to reduce the packet loss rate ?

        Looking forward to your reply ,Thanks a lot .

        Best Regards .

[Maria Gilje]

Hello,

I am looking into this. Thank you for your patience.

Best Regards,
Maria

[hyman]

Thanks

[Maria Gilje]

Hello again,

  I want to know whether the packet loss rate is normal ? What should I do to reduce the packet loss rate ?

I have asked our Thread experts about this. But based on OpenThread's tests, a packet loss rate of 1% seems big.

Please share a sniffer log if you have it. Upload it to your reply as a .pcap-file. If you don't have one, follow these instructions on how to do a sniffer trace with Wireshark.

If you don't want to share a sniffer log on a public ticket I can make it private.

Best Regards,
Maria

[Maria Gilje]

Hello,

Maria Gilje said:

I have asked our Thread experts about this.

Their response is that your amount of packet loss is expected when broadcasting is the transmission method. The reason for this is that broadcasting packets are not acknowledged.

What should I do to reduce the packet loss rate ?

Transmitting with acknowledgements will generally have a lower packet loss rate.

Best Regards,
Maria

[hyman]

Hi,Maria,

        Thanks for your reply .

        If we use UDP socket on openthread network to broadcasting packet ,Can this method add acknowledged ? As far as I know ,TCP has the acknowledged characteristics ,and TCP is a point-to-point communication mode, It doesn't meet our needs . Do you know how to add acknowledged in UDP socket broadcasting .

        If we want to achieve our requirements, and need a low packet loss rate ,Do you have any good implementation methods？

        Best Regards,

        Hyman

[hyman]

Hi，

        Is there any progress on this issue？

        Thanks

[Maria Gilje]

Hello,

If the computers are set up in a client/server configuration, you can include CoAP as a way to provide acknowledgements on top of UDP. You can learn about CoAP in Lesson 5 from IoT Fundamentals on DevAcademy, and you can take a look at the Thread: CoAP Server and Thread: CoAP Client samples. 

Best regards,

Maria