hardMultiple ChoiceObjective-mapped
300-410 Practice Question: A large enterprise network uses EIGRP with route…
A large enterprise network uses EIGRP with route summarization. Router R1 has the following configuration: interface GigabitEthernet0/0, ip summary-address eigrp 100 10.0.0.0 255.255.252.0. Router R2 shows: show ip route eigrp includes 10.0.0.0/22 but not 10.0.3.0/24. What is the root cause?
⚠ Common exam trap
Cisco often tests the misconception that EIGRP summarization simply advertises a summary route in addition to the more specific routes, when in fact the default behavior is to suppress all component routes within the summary range.
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 EIGRP summary address suppresses more specific routes within its range.
The EIGRP `ip summary-address` command on R1 creates a summary route (10.0.0.0/22) that is advertised to R2, and by default EIGRP suppresses the advertisement of all more specific routes that fall within the summary range (10.0.0.0/22 includes 10.0.3.0/24). This is the intended behavior of EIGRP route summarization: the summary route replaces the component routes to reduce routing table size and update overhead.
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 address is misconfigured; it should be 10.0.0.0/24.
Why it's wrong here
The summary is correct for the range; the issue is suppression of specifics.
- ✗
R2 has a route filter blocking 10.0.3.0/24.
Why it's wrong here
No evidence of a filter; the summary suppresses the specific route.
- ✓
The EIGRP summary address suppresses more specific routes within its range.
Why this is correct
EIGRP summary addresses automatically suppress more specific routes, causing the missing /24.
- ✗
R1's interface is down, preventing route advertisement.
Why it's wrong here
The summary is present, so the interface is up.
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.
Go deeper
Related to this question
Learn chapter
Introduction to ENARSI Exam and Network Fundamentals
Key term
EIGRP Route Summarization
EIGRP route summarization is a technique that combines multiple specific network routes into one summary route to reduce routing table size and improve network stability.
Key term
BGP Route Aggregation
BGP Route Aggregation is a technique that combines multiple specific network routes into a single summary route to reduce the size of routing tables and improve network efficiency.
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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.