UDP Server->GE864 packet loss

7 thoughts on “UDP Server->GE864 packet loss”

  1. Hello,

     

    we are using a GE864 FW 7.2.4 to communicate with a server via UDP protocol.

    The provider is vodafone germany with corporate data access (CDA) option (fixed IP).

     

    With this system setup we are experiencing the following behaviour:

    Once a UDP packet has been send from the GE864 to the server, the server can send packets back for aprox. 30s. All server-to-client packets send afterwards are  lost until the client sends a packet again. Then everything is fine again for another 30s.

     

     Are there any known issues regarding this topic (i either need to be sure that this behaviour is caused by the provider or find a solution when it is a client side problem)?

     

    P.S.:  Just sending data every 30s would circumvent this problem but is not really an option in this project

     

    Thanks and best regards,

    Ralf

     

    1. Are packets completely lost or you get ICMP Destination unreachable back to the server? It might be some sort of DOS protection on a firewall on the way.

      Try to:

      – send packets back at a slower pace

      – use UDP listen on module to get packets back instead of the running client

       

      Is it Python or external host?

      1. It is an external host application and the packets are lost completely (at least as far as i know).

         

        The data flow is as following:

        – every 60s  the client sends a UDP packet with aprox. 100 bytes payload to the server (these packets reach the server without problem)

        – the  server responds immediately with an acknowledge UDP packet with aprox. 10 bytes payload (these packets reach the client without problem)

        – ocassionally a special UDP message with aprox. 100 bytes payload is send from  server to client (these packets reach the client when send within aprox. 30s after the last client-to-server-packet and are lost otherwise)

         

        What shall i slow down here?

         

        I’m using the following commands for socket operation:

        // open

        AT#SD=1,1,<dest. port>,<server>,0,<src. port>,1

        // check for data available

        AT#SI

        // get data

        AT#SRECV=1,1500

         // send data

         AT#SSEND=1

         

        Switching to UDP listening mode is not possible (as far as i know) as the UDP listening functions are not available in 7.2.4.

        Besides this it would be a major software change which i’d like to avoid  unless i expect it to significantly improve the situation.

         

    2. Hi Ralf,

      Check from what IP-address and port number Server is receiving data from device (client). Not local IP-addres of device given by GSM network.