When node C receives the RREP from node F, it creates the
route entry and calculates the shortest , which indicates the
next hop is node F when the message whose destination node
is node D arrives at node C. And then, when node C receives
RREP from node D, it will calculates the gap and finds that
gap < shortes , as shown in Fig. 6(a) and (b), node C updates
the route table, and then finally optimal path is found