mediumMultiple Choice
300-410 Practice Question: Runs the following command on Router R1: R1# show…
A network engineer runs the following command on Router R1:
R1# show ip eigrp topology all-links
EIGRP-IPv4 Topology Table for AS(100)/ID(192.168.1.1) Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status
P 10.10.10.0/24, 1 successors, FD is 28160, Qos: 0 via 10.1.1.2 (28160/28160), GigabitEthernet0/0 via 10.2.2.2 (28672/28160), GigabitEthernet0/1 P 10.20.20.0/24, 1 successors, FD is 28160, Qos: 0 via 10.2.2.2 (28160/28160), GigabitEthernet0/1 via 10.3.3.2 (28672/28160), GigabitEthernet0/2
Based on this output, which statement is correct?
⚠ Common exam trap
Cisco tests the EIGRP feasibility condition: a path is a feasible successor only if its reported distance (RD) is strictly less than the feasible distance (FD). A path with RD equal to FD is not a feasible successor, even though it appears as an alternate path in 'show ip eigrp topology all-links'.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The route to 10.20.20.0/24 has no feasible successor.
The EIGRP feasibility condition requires the reported distance (RD) to be strictly less than the feasible distance (FD) for a path to be a feasible successor. In the output, for route 10.20.20.0/24, the FD is 28160, and both paths have an RD of 28160, which equals the FD, not less. Therefore, no feasible successor exists for this route. Option A is incorrect because neither route has a feasible successor. Option C is incorrect because the FD for 10.10.10.0/24 is 28160, not 28672. Option D is incorrect because the route is marked 'Passive', not 'Active'.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The network has redundant paths with feasible successors for both routes.
Why it's wrong here
This statement is incorrect because neither route has a feasible successor. For 10.10.10.0/24, the two paths have RD equal to FD (both 28160), so the second path is not a feasible successor. For 10.20.20.0/24, similarly no feasible successor.
- ✓
The route to 10.20.20.0/24 has no feasible successor.
Why this is correct
This is correct. The feasibility condition requires RD < FD. For 10.20.20.0/24, both paths have RD = 28160 equal to FD, so they are not feasible successors. Thus there is no feasible successor.
- ✗
The FD for 10.10.10.0/24 is 28672.
Why it's wrong here
Incorrect. The FD for 10.10.10.0/24 is 28160, not 28672.
- ✗
The route to 10.10.10.0/24 is in Active state.
Why it's wrong here
Incorrect. The route is marked 'P' for Passive, not Active.
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.