SocketException (The system call was cancelled)

I am working on a android project and I need to connect the gPhone with the PC using UDP socket. The same operation, sending a message to from gPhone to the PC, returns different results in different time: Sometimes succeeded and sometimes throws a SocketException(The system call was cancelled开发者_Go百科).

Can anyone tell me what possibly results in this SocketException?

Add this to your app's manifest:

<uses-permission android:name="android.permission.INTERNET" />