Hey guys, trying to track down a rather elusive problem here... I've been playing around with long-standing TCP connections to a server.
The client opens a TCP connection to the server, sets a timeout at a reasonably long period (30 minutes), and adds an AlarmManager task to "ping" the server every 15 (a ping is just a junk packet the server responds to with an application-level "ack"). Nothing fancy, and everything works correctly on the emulator. The client stays connected to the server for as long as I've left it alone (a few hours easily). However, as soon as it runs on device, I receive some interesting behavior when the device is sleeping (CPU completely off if I understand correctly). If I let the device connect, and go to sleep (can't be 100% certain it is asleep, but I wait a good few minutes). And have the server send an un-expected packet to the client, the client most definitely wakes up, processes the packet, and sends a response. The wakeup noticibly takes a few extra seconds, but this isn't an issue. The issue comes in if I let the device sleep for a more extended period of time (somewhere around 5 minutes). At this time, I see the server drop the connection as reset, and the client sit there sleeping. As soon as the device is woken up (by my intervention), and I try to do any network actions, it notices the connection isn't good anymore, and starts a reconnect (hard-coded to reconnect). I've been running tcpdump on both the client, and the server. The interaction is as follows: Server's point of view: - Client connects (a few packets back and forth, application level, etc) - 5ish minutes pass (device is sleeping) - Client sends a reset packet (connection is torn down, expected) >From the client's point of view: - Connection startup (a few packets back and forth, application level, etc) - Device goes to sleep The client never sees the TCP reset packet. Once woken by something external (me, the AlarmManager task, etc), the client immediately sees a RST packet from the server, tears down the connection, and starts over. Anyone care to chime in with ideas as to what is happening? My only thoughts are that someone in between is killing the connection due to not seeing any data send between the two after a certain amount of time, however the time between the last packet, and the RST isn't a consistent period... This behavior is happening when running a G1 on Tmobile's 3g US network. It happens when the server code is running both remotely (machine in Texas), as well as when its running on local machine (Florida). -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
