public Link(String local_addr, int local_port, String remote_addr, int remote_port, Receiver r) { this(local_addr, local_port, remote_addr, remote_port); setReceiver(r);
public Link(String local_addr, int local_port, String remote_addr, int remote_port) { this.local_addr=local_addr;   this.local_port=local_port; this.remote_addr=remote_addr; this.remote_port=remote_port; hb=new Heartbeat(timeout, hb_interval);
    public Link(String local_addr, int local_port, String remote_addr, int remote_port, Receiver r) {	this(local_addr, local_port, remote_addr, remote_port);	setReceiver(r);    }