How can I test a RTP(send&receive) application on the same computer?

Question

I an writing an application that lets one computer (A) sends a media file to another computer (B) and B receives it and play it.
But how can I test this application on the same computer
Eg.Transmitter: localhost 43000
Receiver: localhost 43000
It will retuen an error since the port number is alreeady used by another program.
I know if I test it on different computers, it should be fine, but how can I test it on the same computer?

Answer 1

JMStudio sends RTP packets from the same UDP port as the specified in the destination port, so you can't try it in the same computer. The examples provided in http://java.sun.com/products/java-media/jmf/2.1.1/solutions/index.html follow this rule aswell, but it's easy to modify it:
rtpMgrs[streamid]=RTPManager.newInstance();
localAddr = new SessionAddress( InetAddress.getLocalHost(),localDataPort);
//By deafault, in the examples, they use  remote DataPort instead of localDataPort.
//You can specify localDataPort to any different free port number, or to
//SessionAddress.ANY_PORT if you don't mind the port number
remoteAddr  = new SessionAddress(destIpAddr,remoteDataPort);
rtpMgrs[streamid].initialize(localAddr);
rtpMgrs[streamid].addTarget(remoteAddr);