I'm experiencing the following: a piece of software that we wrote keeps a TCP connection open to our server (yes, we need it to get callbacks from the server and SMS is not an option unfortunately).
The connection works fine for 8-9 hours. After that, the connection dies and every attempt to re-establish it fails with a timeout. Even if I close our application and try with a browser or any other application, same thing happens: connection timeout.
But I've noticed that if I place a phone call (normal voice call), when the call has ended, I can use my GPRS connection again ... That's definitely weird, I'm going to experiment some more.
Does anyone have any ideas? Could the operator be limiting the duration of my GPRS sessions? Is there a limit in the phone itself that might kill the connection after 8-9 hours?