4.(20 points) Link-state routing protocols This question explores how to set the (configurable) link weights in link-state routing protocols like OSPF inside a single Autonomous System (AS) to achieve AS-wide goals. a) How should the network operators set the link weights if their goal is to minimize the number of hops each packet traverses to reach its destination? b) How should the operators set the link weights to minimize the end-to-end delay the traffic experiences? Assume the network is lightly loaded, so queuing delay is insignificant. c) Using the Dijkstra shortest-path algorithm, one can compute the shortest path from node u to all network nodes. Given a 6-node network illustrated in the figure below. The table underneath indicates the steps deriving the cost (denoted by D) and previous hop (denoted by p) on the shortest paths. V w 3 2 5 2 1 Travel Set u ux uxy ux uxyw uxywz D(V).p(v) D(w),p(w) D(x),p(x) D(y),p(y) D(z).p(z) 2,u 5.0 1,0 infinity infinity 2,u 4, 2.x infinity 2,u 3.7 4. 3.y 4. 4. Now, consider the 7-node network illustrated in the figure below. Generate the table indicating the steps deriving the cost and previous hop on the shortest paths from node a to all other network nodes. Note that when the path costs are equal, add nodes to the Travel Set in alphabetic order