Q54

Consider a network with $6$ routers $\textbf{R1}$ to $\textbf{R6}$ connected with links having weights as shown in the following diagram.

All the routers use the distance vector based routing algorithm to update their routing tables. Each router starts with its routing table initialized to contain an entry for each neighbor with the weight of the respective connecting link. After all the routing tables stabilize, how many links in the network will never be used for carrying any data?