The Routing Table at R2: Same Destination, Different Forwarding Instructions

The Routing Table at R2: Same Destination, Different Forwarding Instructions

Like R1 before it, R2 next looks at the destination address of the packet, and it compares the address to the routing table. Like R1, R2 should match an entry in the table, and that entry tells R2 what to do with the packet. However, R2's routing table differs from R1's because R2's routing table includes instructions about how R2 should forward IP packets. It's like taking a trip where you turn left at one intersection and right at another. The turn you make depends on where you are. Likewise, the instructions about which interface out which to forward a packet depends on where the router is in the internetwork. Figure 11-12 shows R1's and R2's routing tables to illustrate how R2 behaves differently from R1.