ltmap file so that it does the proper calculation of delay, bandwidth,
and loss, as it is done in assign_wrapper. More specifically, the
delay/bandwidth/loss between two nodes in a lan is a function of nodea
delay/bandwidth/loss, and nodeb rdelay/rbandwidth/rloss, where the "r"
values are for the "from the lan to the node" direction.  These might
very well be different then the other values for asymmetric links.