hardMultiple 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 route 10.0.0.0 255.255.252.0 longer-prefixes
Routing entry for 10.0.0.0/22 Known via "eigrp 100", distance 90, metric 2172416, type internal Last update from 192.168.1.2 on GigabitEthernet0/0, 00:00:10 ago Routing Descriptor Blocks:
* 192.168.1.2, from 192.168.1.2, 00:00:10 ago, via GigabitEthernet0/0
Route metric is 2172416, traffic share count is 1
Routing entry for 10.0.1.0/24 Known via "eigrp 100", distance 90, metric 2812416, type internal Last update from 192.168.1.2 on GigabitEthernet0/0, 00:00:10 ago Routing Descriptor Blocks:
* 192.168.1.2, from 192.168.1.2, 00:00:10 ago, via GigabitEthernet0/0
Route metric is 2812416, traffic share count is 1
Based on this output, what is the effect of the summary route 10.0.0.0/22?
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 summary route is not suppressing the more specific route 10.0.1.0/24.
The presence of both the summary route (10.0.0.0/22) and a more specific route (10.0.1.0/24) in the routing table indicates that the summary route is not suppressing the more specific routes, possibly due to a configuration issue or because the summary is not configured as a discard route.
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 summary route is working correctly and suppressing all specifics.
Why it's wrong here
The specific 10.0.1.0/24 still appears alongside the /22, so suppression is not occurring; suppression requires the summary to be advertised with a discard or null route. It tempts because correctly configured EIGRP auto-summary or manual summarisation does hide component routes, which is the intended design in a working deployment.
- ✓
The summary route is not suppressing the more specific route 10.0.1.0/24.
Why this is correct
EIGRP advertises the 10.0.0.0/22 summary alongside the component 10.0.1.0/24, which remains in the routing table as a separate entry. The summary is not suppressing that more specific route, so both prefixes appear in the output.
- ✗
The summary route has a better metric than the specific route.
Why it's wrong here
The /22 carries metric 2172416 while the /24 carries 2812416, so the summary is numerically lower, not higher; the option inverts the displayed values. It tempts because longest-prefix match, not metric, decides forwarding, and engineers often assume the summary must win on metric to be preferred.
- ✗
The summary route is not installed in the routing table.
Why it's wrong here
The output lists 10.0.0.0/22 as a routing entry learned via EIGRP, so it is installed; the premise of this option contradicts the displayed table. It tempts because summarisation with a null interface can leave a summary absent until a component route appears, which is a real EIGRP behaviour in other configurations.
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.