nse would fail if there were only rlinks on a simnode. The problem wouldn't
occur if a normal duplex link was created first. The reason is coz the creation of an rlink would also internally create an IPTap agent and when this agent was being attached to the node, classifier entries were being added to the port demultiplexer for all the IP addresses of the simnode. Unfortunately, if an rlink was created first before anything else, the IP address would be set only in the next Tcl statement causing nse to exit prematurely.