I have scoured the interwebz with no result. We are facing a problem where some Android devices experience severe packet loss. To give some background, the application connects to a specific Wifi and looks for UDP packets broadcast on port 17216. These packets are of size 832 bytes, excluding the wrapped headers, and are sent at a regular rate of four per second.
We have only met the problem on two devices, a low-end Turbox Rubik II tablet and an ASUS Memo Pad HD 7. The other devices we've tested (phones and tablets) all gather the packets at the stipulated regular interval.
The function that receives the packets is this:
public void run()
{
while (isUDPServerRunning)
{
try
{
socket.receive(packet);
ProcessRawPacketData();
DisplayLoggingInfo();
}
catch (IOException e)
{
Log.e("receive", e.getMessage());
e.printStackTrace();
}
}
}
And that is part of a Runnable. The socket is created thus:
byte[] buffer = new byte[1024];
DatagramSocket socket;
DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
with the socket being initialized in the onCreate() method of our Service extension:
socket = new DatagramSocket(SERVERPORT);
The packets are being received by the Wifi module. We've confirmed that by rooting one of the devices and installing a packet sniffer, so the problem must somehow be code related.
On the affected devices packets are received correctly for a couple of seconds and then there is complete dropout that lasts for several seconds, so I estimate the loss to exceed 50%.
Any help would be much appreciated. We are pulling our hair out.
Update I was mistaken about the packet sniffer. It seems that the packet sniffer is also losing several relevant packets on the rooted device. Sometimes, though, simply starting the packet sniffer fixes the issue! Turning Bluetooth on/off like suggested below does not seem to make a difference. Could this be another hardware issue?
Update 2 Here is an example of the logs I'm printing immediately after the socket.receive() line. Notice how it skips half a minute's worth of packets and then works fine for a few seconds.
05-25 15:44:38.670: D/LOG(4393): Packet Received
05-25 15:44:38.941: D/LOG(4393): Packet Received
05-25 15:45:09.482: D/LOG(4393): Packet Received
05-25 15:45:09.716: D/LOG(4393): Packet Received
05-25 15:45:09.928: D/LOG(4393): Packet Received
05-25 15:45:10.184: D/LOG(4393): Packet Received
05-25 15:45:10.451: D/LOG(4393): Packet Received
05-25 15:45:10.661: D/LOG(4393): Packet Received
