hardMultiple ChoiceObjective-mapped
300-410 Practice Question: An engineer configures Control Plane Policing…
An engineer configures Control Plane Policing (CoPP) on a router. After configuration, OSPF neighbors are flapping. Which is the most likely explanation?
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 class-default is configured with a police action that drops OSPF packets exceeding the rate.
CoPP applies a policy-map to the control plane. If the default class-default is used without an explicit permit for OSPF packets, the implicit deny at the end of the policy-map will drop OSPF packets. The default class-default action is 'drop' if not explicitly configured, but even if a 'police' action is configured, the default behavior is to drop packets that exceed the rate.
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 class-default is configured with a police action that drops OSPF packets exceeding the rate.
Why this is correct
If OSPF packets are not explicitly classified and permitted, they fall into class-default. The police action in class-default will drop packets that exceed the configured rate, causing OSPF hello packets to be dropped and neighbors to flap.
- ✗
The CoPP policy is applied to the wrong direction (input vs output).
Why it's wrong here
Applying CoPP in the wrong direction would not affect OSPF packets because OSPF uses multicast and is processed by the control plane.
- ✗
The access-list used to classify OSPF packets is missing the 'permit' statement for OSPF protocol.
Why it's wrong here
If the access-list is missing the permit, OSPF packets would fall into class-default, which is the same issue, but the more direct explanation is the class-default behavior.
- ✗
The CoPP policy uses 'drop' action for OSPF class.
Why it's wrong here
If the engineer explicitly configured a drop action for OSPF, that would be intentional, not a misconfiguration.
Visual reference
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
About these practice questions
This 300-410 question is part of Courseiva's 1,966-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
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.