ch1.setReceiver(receiver1);
ch2.setReceiver(receiver2);
ch3.setReceiver(receiver3);
// all channels will discard messages with seqno #3 two times, the let them pass
ch1.getProtocolStack().insertProtocol(new DISCARD_PAYLOAD(), ProtocolStack.BELOW, "NAKACK");
ch2.getProtocolStack().insertProtocol(new DISCARD_PAYLOAD(), ProtocolStack.BELOW, "NAKACK");
ch3.getProtocolStack().insertProtocol(new DISCARD_PAYLOAD(), ProtocolStack.BELOW, "NAKACK");
ch1.connect("x");
ch2.connect("x");
ch3.connect("x");