Routing protocol specifies how routers perform the network connectivity algorithms and distribute information across the nodes. Categorized as static, default and dynamic routing protocols. Link-state and distance vector are dynamic routing protocols. Distance vector routing protocols are based on "routing by rumour" principle. ie perform its routing operations based on the communication with the directly connected neighbor and does not have an overview or full knowledge of the entire network, slower to converge and good for the small networks, This category includes RIP and EIGR. while Link State routing protcols have an overview (exact map) of the entire network. I know everything that moves. They have information about each link ( current status: up/down, speed, etc). This includes OSPF and IS-IS protocols. it converges faster, updates are triggered by events and uses hello to connects to its neighbor. NB: You can expatiate further on the behavior of each routing protocols such as the OSPF on link state hello messages, updating its routing table and calculating the shortest path using the Bellman-Ford algorithm. The RIP update time every 30-sec repetitively, learning the routes of the directly connected neighbor and storing of the information its routing table.