M66 Server Mode, QIRDI-statement not sent


we are using the M66 module in server and client mode.
The procedure in client mode is as follows:

  1. Opening connection to server
  2. Sending data
  3. Getting acknowledge
  4. Closing connection

In Server mode:

  1. Getting the QIRDI-statement via UART
  2. Retrieving all date with AT+QIRD command
  3. Sending data
  4. Getting acknowledge
  5. Closing connetion

We only have a problem in server mode. If we get frequent request (every minute) everything works fine. But if we request the server only every hour, after severel request the QIRDI-statement will not be sent via UART anymore. I have checked the listening state with the AT+QISSTAT command and the server is still in listening mode.
In the document Quectel_GSM_TCPIP_Recommended_Process capter 6 it is described that due to inactivity the GPRS gateway can release a port without information. Following on there is a method given how to detect/ maintain the connection. But for my understanding this only works for the client mode. Can you recommend a method for server mode also?

For now I’m handling this in the way that if the server has not been requested for an hour I deactivate the PDP-context and reactivate it immediately again. Is this the right way, or is there a better way? And will this reactivation cause extra cost?

Best regards!

Hi, guy, I am so sorry for replying late. Your problem is complicated, I need to disscuss with my fellows, I will support you as soon as possible.