- A
The CoPP policy rate-limits EIGRP packets to 1 Mbps, but EIGRP hellos are small and frequent; the rate-limit may still drop them if the policer is not properly configured for burst.
Even small packets can be dropped if the policer uses a strict rate without adequate burst size.
- B
R2 is sending too many EIGRP packets, exceeding the rate-limit.
Why wrong: The issue is the policer, not excessive traffic.
- C
R1 has an ACL that blocks EIGRP packets before they reach the control plane.
Why wrong: CoPP is applied to the control plane, not an ACL.
- D
The CoPP policy is applied to the wrong interface.
Why wrong: CoPP is applied globally to the control plane, not per interface.
Question 1,459 of 2,152
300-410 EIGRP Troubleshooting Practice Question
This 300-410 practice question tests your understanding of eigrp troubleshooting. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network uses Control Plane Policing (CoPP) to protect the router. Router R1 has CoPP policy applied that rate-limits all traffic to 1 Mbps. R1 shows: 'show policy-map control-plane' indicates drops for EIGRP packets. R1's EIGRP neighbor R2 is flapping. What is the root cause?
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 CoPP policy rate-limits EIGRP packets to 1 Mbps, but EIGRP hellos are small and frequent; the rate-limit may still drop them if the policer is not properly configured for burst.
EIGRP hello packets are small and sent frequently (every 5 seconds on most LAN interfaces by default). A CoPP policer that rate-limits all traffic to 1 Mbps without an adequate burst parameter will treat the burst of small hello packets as exceeding the committed burst (Bc), causing drops. These drops prevent EIGRP neighbor keepalives from reaching the control plane, leading to neighbor flapping. The root cause is not the total bandwidth but the policer's inability to accommodate the packet-per-second (PPS) burst of small EIGRP hellos.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 CoPP policy rate-limits EIGRP packets to 1 Mbps, but EIGRP hellos are small and frequent; the rate-limit may still drop them if the policer is not properly configured for burst.
Why this is correct
Even small packets can be dropped if the policer uses a strict rate without adequate burst size.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
R2 is sending too many EIGRP packets, exceeding the rate-limit.
Why it's wrong here
The issue is the policer, not excessive traffic.
- ✗
R1 has an ACL that blocks EIGRP packets before they reach the control plane.
Why it's wrong here
CoPP is applied to the control plane, not an ACL.
- ✗
The CoPP policy is applied to the wrong interface.
Why it's wrong here
CoPP is applied globally to the control plane, not per interface.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that CoPP drops are caused by exceeding the bandwidth rate-limit, when in reality the trap is that small, frequent control-plane packets (like EIGRP hellos) are dropped due to an insufficient burst size, not the overall traffic rate.
Detailed technical explanation
How to think about this question
CoPP uses a token-bucket policer with parameters: committed information rate (CIR) and committed burst (Bc). For EIGRP hellos, the packet rate (PPS) can be high even at low bandwidth; if Bc is set too low (e.g., default 1500 bytes), a burst of multiple hellos arriving in a short interval will exceed the bucket depth and be dropped. This is a common misconfiguration when CoPP is applied with a simple 'rate-limit' without adjusting the burst size for small-packet protocols like EIGRP, OSPF, or BGP keepalives.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
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.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
EIGRP Troubleshooting — study guide chapter
Learn the concepts, then practise the questions
- →
EIGRP Troubleshooting practice questions
Targeted practice on this topic area only
- →
All 300-410 questions
2,152 questions across all exam domains
- →
Cisco CCNP ENARSI 300-410 study guide
Full concept coverage aligned to exam objectives
- →
300-410 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related 300-410 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Layer 3 Technologies practice questions
Practise 300-410 questions linked to Layer 3 Technologies.
EIGRP Troubleshooting practice questions
Practise 300-410 questions linked to EIGRP Troubleshooting.
OSPF Troubleshooting (v2/v3) practice questions
Practise 300-410 questions linked to OSPF Troubleshooting (v2/v3).
BGP Troubleshooting practice questions
Practise 300-410 questions linked to BGP Troubleshooting.
Route Redistribution practice questions
Practise 300-410 questions linked to Route Redistribution.
Policy-Based Routing (PBR) practice questions
Practise 300-410 questions linked to Policy-Based Routing (PBR).
VRF-Lite practice questions
Practise 300-410 questions linked to VRF-Lite.
Route Maps and Route Filtering practice questions
Practise 300-410 questions linked to Route Maps and Route Filtering.
Administrative Distance practice questions
Practise 300-410 questions linked to Administrative Distance.
Route Summarization practice questions
Practise 300-410 questions linked to Route Summarization.
Bidirectional Forwarding Detection (BFD) practice questions
Practise 300-410 questions linked to Bidirectional Forwarding Detection (BFD).
VPN Technologies practice questions
Practise 300-410 questions linked to VPN Technologies.
Practice this exam
Start a free 300-410 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this 300-410 question test?
EIGRP Troubleshooting — This question tests EIGRP Troubleshooting — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The CoPP policy rate-limits EIGRP packets to 1 Mbps, but EIGRP hellos are small and frequent; the rate-limit may still drop them if the policer is not properly configured for burst. — EIGRP hello packets are small and sent frequently (every 5 seconds on most LAN interfaces by default). A CoPP policer that rate-limits all traffic to 1 Mbps without an adequate burst parameter will treat the burst of small hello packets as exceeding the committed burst (Bc), causing drops. These drops prevent EIGRP neighbor keepalives from reaching the control plane, leading to neighbor flapping. The root cause is not the total bandwidth but the policer's inability to accommodate the packet-per-second (PPS) burst of small EIGRP hellos.
What should I do if I get this 300-410 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More 300-410 practice questions
- Drag and drop the steps to negotiate an IKEv2 IPsec site-to-site tunnel into the correct order, from first to last.
- Drag and drop the steps to troubleshoot an IPsec site-to-site VPN adjacency failure into the correct order, from first t…
- Drag and drop the steps to verify and validate the operational state of an IPsec site-to-site VPN into the correct order…
- Consider the following configuration snippet: ip cef ! interface GigabitEthernet0/0 ip address 10.0.0.1 255.255.255.25…
- A router is configured with 'logging host 10.1.1.100' and 'logging trap informational'. The engineer notices that syslog…
- Drag and drop the steps to configure a GRE tunnel for IPv6 over IPv4 into the correct order, from first to last.
Last reviewed: Jul 4, 2026
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.