hardMultiple Choice
300-410 Practice Question: Runs the following command to troubleshoot a…
A network engineer runs the following command to troubleshoot a Control Plane Policing (CoPP) issue:
R1# show policy-map control-plane input class CoPP-Class
Class-map: CoPP-Class (match-all) 1500 packets, 120000 bytes 5 minute offered rate 10000 bps, drop rate 5000 bps Match: access-group name CoPP-ACL police: cir 8000 bps, bc 1500 bytes, be 1500 bytes conformed 1000 packets, 80000 bytes; actions: transmit exceeded 500 packets, 40000 bytes; actions: drop conformed 8000 bps, exceed 2000 bps, violated 0 bps
What does this output indicate?
⚠ Common exam trap
Cisco often tests the misinterpretation of CoPP output statistics, where candidates confuse the 'drop rate' with the 'exceed rate' or assume that a high drop rate always indicates a misconfiguration, rather than recognizing that it shows the policer is actively dropping traffic that exceeds the CIR, which may be intentional or problematic depending on the traffic class.
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 is causing packet loss for traffic that exceeds the 8 kbps rate, which may impact legitimate control plane traffic.
The output shows that the CoPP policy uses a CIR of 8000 bps with a conformed rate of 8000 bps and an exceed rate of 2000 bps. The drop rate of 5000 bps indicates that traffic exceeding the CIR is being dropped, which can include legitimate control plane traffic (e.g., routing protocol packets) if they are classified under the CoPP-Class. This confirms that the policy is causing packet loss for traffic that exceeds the 8 kbps rate, potentially impacting critical control plane operations.
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 is dropping all traffic because the CIR is too low.
Why it's wrong here
Drops are partial, not total: 1000 packets conformed and transmitted while 500 exceeded and were dropped, so the policer is working as configured. It is tempting because a low CIR does cause drops, but 8000 bps is the configured limit, not a fault.
- ✓
The CoPP policy is causing packet loss for traffic that exceeds the 8 kbps rate, which may impact legitimate control plane traffic.
Why this is correct
The police statement enforces a committed information rate of 8000 bps, and the exceeded counter shows 500 packets dropped once traffic surpassed that threshold. Because CoPP polices traffic destined to the route processor, this loss can discard legitimate routing protocol and management packets, degrading adjacency stability and remote access.
- ✗
The CoPP policy is not applied correctly because the drop rate is higher than the conform rate.
Why it's wrong here
Drop rate exceeding conform rate is expected behaviour under policing, not evidence of misapplication; exceeded packets are dropped by design. It tempts because the numbers look alarming, but the policy is correctly attached and enforcing the configured cir, so the counters alone do not prove a fault.
- ✗
The CoPP policy is working as intended with no issues.
Why it's wrong here
The exceeded counter shows 500 packets dropped against a cir of 8000 bps, so traffic is being policed and discarded, not passed cleanly. It tempts because conformed traffic is transmitted, but a non-zero drop rate against offered traffic indicates the policy is actively limiting legitimate packets.
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.
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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.