VoIP with JMF

[Stanley George]

hello friends,
i have tried VoIP using datasink. the datasink has the IP address of the receiver. receiver listens at its own IP address. works perfect.
the problem is, i want to reverse the IP address requirement. i.e i want the receiver to listen at the IP address of the transmitter. i tried it but i am not getting any audio.am i missing something here?
any and all suggestions are welcome
thank you very much
stanley