Question 406 of 2,152
Control Plane Policing (CoPP)hardMultiple ChoiceObjective-mapped

How to Read CoPP Police Statistics and Identify Packet Drops

This 300-410 practice question tests your understanding of control plane policing (copp). The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 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?

Quick Answer

The answer is that the CoPP policy is causing packet loss for traffic that exceeds the 8 kbps rate, which may impact legitimate control plane traffic. This is correct because the output from the show policy-map control-plane input class CoPP-Class command reveals a clear mismatch: the offered rate is 10 kbps, but the committed information rate (CIR) is only 8 kbps, causing the policer to drop 500 packets in the exceeded bucket. On the Cisco CCNP ENARSI 300-410 exam, this scenario tests your ability to interpret CoPP police statistics and identify packet drops, specifically recognizing that a drop rate of 5000 bps alongside a conformed rate of 8000 bps indicates legitimate traffic is being throttled. A common trap is focusing only on the conformed packets count while ignoring the exceeded actions—remember that the drop rate always subtracts from the offered rate. Memory tip: “Offered minus CIR equals drop risk”—if the offered rate exceeds the CIR, expect drops in the exceeded bucket.

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.

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 is dropping all traffic because the CIR is too low.

    Why it's wrong here

    Only exceeding packets are dropped; conforming traffic is transmitted.

  • 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 drop rate of 5 kbps indicates that half the offered traffic is being dropped, which could affect protocols like OSPF or BGP.

    Related concept

    Read the scenario before looking for a memorised answer.

  • The CoPP policy is not applied correctly because the drop rate is higher than the conform rate.

    Why it's wrong here

    This is expected behavior when the offered rate exceeds the CIR.

  • The CoPP policy is working as intended with no issues.

    Why it's wrong here

    The high drop rate suggests a potential problem if the dropped traffic includes critical control plane packets.

Common exam traps

Common exam trap: answer the scenario, not the keyword

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.

Detailed technical explanation

How to think about this question

CoPP uses a policer (typically single-rate two-color or three-color) to rate-limit control plane traffic; in this case, the 'police' command with cir 8000 bps, bc 1500 bytes, and be 1500 bytes implements a single-rate two-color policer where conformed traffic is transmitted and exceeded traffic is dropped. The 'show policy-map control-plane' output displays the conformed and exceeded rates, which are calculated over a 5-minute interval; the drop rate (5000 bps) reflects the exceeded traffic, and if the CoPP-ACL matches critical protocols like OSPF or BGP, this drop rate could cause routing instability or session flaps.

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 security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.

Visual reference

Source Router + ACL permit 10.0.0.0/8 deny any Server 10.0.0.5 ✓ 192.168.1.1 ✗ dropped ACLs evaluate top-down; first match wins — implicit deny all at end

Quick reference

Routing Protocol Comparison

ProtocolMetricMax HopsAlgorithmType
RIP v2Hop count15Bellman-FordDistance vector
OSPFCost (bandwidth)UnlimitedDijkstra (SPF)Link state
EIGRPComposite metricUnlimitedDUALHybrid
IS-ISCostUnlimitedDijkstraLink state
BGPPolicy / attributesUnlimitedPath vectorPath 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.

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.

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?

Control Plane Policing (CoPP) — This question tests Control Plane Policing (CoPP) — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: 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.

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 →

How Courseiva writes practice questions · Editorial policy

Keep practising

More 300-410 practice questions

Last reviewed: Jul 4, 2026

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.

Loading comments…

Sign in to join the discussion.

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.