R1 Learning by Listening for Routing Updates

Each router knows only its respective, directly connected routes, as shown by the routing tables at the top of the figure.

R2 sends a routing update to R1.

R1's routing table now holds a route to subnet 150.1.3.0. Also, notice that R1's outgoing interface for that route is Ethernet2, which is the interface in which the routing update was received. The next-hop router is 150.1.2.2, which is R2's IP address.