EIGRP data structures — where are successor routes stored? In Enhanced IGRP (EIGRP), identify where successor routes (the best next hops) are retained during normal operation.

Introduction / Context:
EIGRP maintains three core data structures: the neighbor table (adjacent routers), the topology table (all learned routes with metrics), and the routing table (best routes chosen for forwarding). Understanding which table holds which routes is essential for troubleshooting convergence and reachability.

Given Data / Assumptions:

• Successor routes are the current best next hops to each destination.
• EIGRP may also keep feasible successors as backups in the topology table.
• We are focusing on where successor routes reside during steady state.

Concept / Approach:
By design, EIGRP installs successor routes into the routing table for forwarding, and also records them in the topology table along with other candidates. The neighbor table does not store routes; it stores adjacency information (IP, hold time, SRTT, RTO, queue counts). Feasible successors remain in the topology table and can be promoted if the successor fails and feasibility condition is met.

Step-by-Step Solution:
Identify successor routes as the currently selected best paths.Confirm their presence in the routing table for actual forwarding.Recognize that the topology table contains all learned paths including the active successor.Therefore, successor routes are in both the routing table and the topology table.

Verification / Alternative check:
Use show ip route eigrp to view installed successors and show ip eigrp topology to see successors and feasible successors with metrics such as feasible distance and reported distance.

Why Other Options Are Wrong:

• A/C: Each lists only one table; EIGRP uses both.
• B/E: The neighbor table holds adjacency statistics, not routes.

Common Pitfalls:
Confusing the neighbor table with the topology table, or assuming feasible successors are always installed in the routing table (they are not unless promoted).

Final Answer:
In the routing table and the topology table