Fig. Q4 shows the link-state database of a network with 6 nodes. (a) Use Dijkstra's algorithm to find the shortest path tree for node C (8 marks) (b) Suppose that the MOSPF is adopted for multicast routing in this network. The sources of the group are connected to node A and group members are connected to (10 marks) (c) Suppose that the multicast routing protocol of the network is changed to PIM-SM. node B, C and D. Use Dijkstra's algorithm to find the shortest path tree for node C The node D is chosen as the rendezvous point. Describe the operation of the PIM- SM protocol and devise the multicast tree. (7 marks) 0 0 Fig. Q4