IGP

In a campus network, if one uplink fails, traffic should quickly switch to the other path. If a distribution switch reboots, access-layer devices should not keep sending traffic to it for a long time. If a new subnet is added, the rest of the domain should soon know where to send that prefix. The hard part in cases like these is not whether there is a static route. It is how many devices inside one autonomous system can quickly form a consistent judgment after the topology changes.