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Message:

MulticastSocket problem in Windows 2000

Posted by John Isner on February 11, 2002 at 11:02 AM

I'm seeing strange behavior with MulticastSockets on a Windows 2000 machine. I'll describe the behavior giving as little detail as possible.

I have two java programs, a game and a player. The game broadcasts DatagramPackets containing "ball" information and "status" information on broadcast addresses, 230.0.0.1 and 230.0.0.2, respectively. The player starts two threads; each monitors one of the broadcast addresses:

class Player{
class BallListener implements Runnable{
public void run(){
// create socket and joinGroup 230.0.0.1
while(true){
socket.receive(packet);
...
}
}
}
class StatusListener implements Runnable{
public void run(){
// create socket and joinGroup 230.0.0.2
while(true){
socket.receive(packet);
...
}
}
}
main(String[] args){
new Thread(new StatusListener()).start(); // line 1
new Thread(new BallListener()).start(); // line 2
...

Now for the strange behavior: When I run the player, each thread receives BOTH kinds of messages. Has anybody seen this behavior?

• send code ping203 February 12, 2002 at 4:25 PM (1)
  • here is the code John Isner February 13, 2002 at 9:53 AM (0)