code: private int isPredecessorOrSelfOf(final NetworkNode networkNode) {
  
  		NetworkNode tmp = networkNode;
  		int steps = 0;
  		while (tmp != null) {
  
  			if (this.equals(tmp)) {
  				return steps;
  			}
  
  			tmp = tmp.getParentNode();
  			++steps;
  		}
  
  		return -1;
  	}
docs: Checks whether this node is a predecessor or the identity (the node itself) of the given network node in the
  network topology tree.
  
  @param networkNode
  a potential child network node
  @return If this node node is a predecessor of given node in the network topology tree, the return value
  indicates the distance between both nodes. If the given node equals this node, the
  return value is <code>0</code>. Otherwise the return value is <code>-1</code>.