}
private void createChannels(boolean copy_multicasts, boolean copy_unicasts, int num_outgoing_copies, int num_incoming_copies) throws Exception {
a=createChannel(true, 3, "A");
DUPL dupl=new DUPL(copy_multicasts, copy_unicasts, num_incoming_copies, num_outgoing_copies);
ProtocolStack stack=a.getProtocolStack();
stack.insertProtocol(dupl,ProtocolStack.BELOW,NAKACK2.class);
b=createChannel(a, "B");
c=createChannel(a, "C");