Socket seems too slow...maybe java.nio?

Question

Hello
In our system I have to receive Multicast Packets repeats very quick(1-5 ms). I have to link them one after an other in the order they sent. And if I miss a packet, something will go wrong...
I have to listen to different IPs and I use different threads for different IPs. If I use only one thread (and listens to only one IP) everything seems ok.
But if I starts listening to an other ip too, I miss 2 packets in a row, or only one if I turn off parsing the message (XML).
Here is the code I use in the Threads:
try{
               socket = new MulticastSocket(port);
               socket.setSoTimeout(1000);
               inetAddress = InetAddress.getByName(ip);
               NetworkInterface nInterface=
NetworkInterface.getByName(networkInterface);
               if(nInterface!=null)socket.setNetworkInterface(nInterface);
               socket.joinGroup(inetAddress);
          catch(IOException ioe){
               logger.error(ioe.getMessage(), ioe);
return;
          try{
               while (!interrupted()) {
                    try{
                         byte[] buffer = new byte[1480];
                         packet = new DatagramPacket(buffer, buffer.length);
                         socket.receive(packet);
parse(buffer);
                    }catch(SocketTimeoutException stoe){
                         //     DO NOTHING
                    }catch(IOException ioe){
                         logger.error(ioe.getMessage(), ioe);
          }finally{
               try {
                    if(socket!=null){
                         socket.leaveGroup(inetAddress);
               } catch (IOException ioe) {}
Every Thread has its own parsing object.
Any tips, what is wrong?
Maybe java.nio could solve the problem somehow. There is a sample server in [Java Home]/sample/nio/server and it suggest that there are quicker methods to receive messages from different IPs (maybe Blocking/Pooled-Thread Server). But I can't understand the API and the Sample while I was reading it (20-30 minutes).
Could it be quicker? Does it worth toying with the idea?
Thanks:
Bence

Answer 1

In our system I have to receive Multicast Packets
repeats very quick(1-5 ms). I have to link them one
after an other in the order they sent. And if I miss
a packet, something will go wrong...There is no guarantee anywhere in the system that you won't miss a datagram. UDP doesn't make such guarantees. If you need all the packets you will have to build ACK or NACK into your protocol.
You can alleviate the problem by running a very large socket receive buffer. But you can't eliminate it. Rethink this.
NIO is not significantly quicker for applications like this, it is more scalable.