How does EIGRP maintain its topology information?

EIGRP, or Enhanced Interior Gateway Routing Protocol, maintains its topology information primarily through consistent updates from neighboring routers. This protocol employs a distance-vector routing technique combined with link-state characteristics to share routing information. When a router running EIGRP establishes a relationship with its neighbors, it exchanges routing information using EIGRP packets, which include both routing updates and topology changes.

These updates are crucial because they not only provide information about directly connected networks but also reflect changes in the network’s state, allowing routers to maintain accurate and up-to-date information about possible routes to all reachable networks. Such consistency ensures that all routers within an EIGRP domain have a synchronized view of the topology, which is essential for making informed routing decisions.

In the context of the other options, static routing entries do not adapt dynamically to changes in network topology, thus they can't maintain topology information effectively. Storing only reachable routes would not give a complete view of the network and could lead to suboptimal routing. Lastly, ignoring received update or query packets would prevent routers from learning about new or changed routes and compromise the overall efficiency and accuracy of the routing process.