hardMultiple ChoiceObjective-mapped
CoPP Show Policy-Map Control-Plane Statistics
A network engineer runs the following command on Router R1:
R1# show policy-map control-plane
Control Plane
Service-policy input: CoPP-POLICY
Class-map: BGP-CLASS (match-all) 50 packets, 2500 bytes 5 minute offered rate 500 bps Match: access-group name BGP-ACL police: cir 64000 bps, bc 8000 bytes, be 8000 bytes conformed 50 packets, 2500 bytes; actions: transmit exceeded 0 packets, 0 bytes; actions: drop violated 0 packets, 0 bytes; actions: drop
Class-map: SNMP-CLASS (match-all) 200 packets, 10000 bytes 5 minute offered rate 2000 bps Match: access-group name SNMP-ACL police: cir 16000 bps, bc 2000 bytes, be 2000 bytes conformed 150 packets, 7500 bytes; actions: transmit exceeded 40 packets, 2000 bytes; actions: drop violated 10 packets, 500 bytes; actions: drop
Class-map: class-default (match-any) 100 packets, 5000 bytes 5 minute offered rate 1000 bps Match: any police: cir 32000 bps, bc 4000 bytes, be 4000 bytes conformed 100 packets, 5000 bytes; actions: transmit exceeded 0 packets, 0 bytes; actions: drop violated 0 packets, 0 bytes; actions: drop
Based on this output, what can be concluded?
Quick Answer
The correct conclusion is that SNMP traffic to the control plane is experiencing drops due to exceeding its policer rate, while BGP traffic is within its rate. This is determined by interpreting the CoPP show policy-map control-plane statistics, where the police counters reveal how many packets conformed, exceeded, or violated the configured CIR. In the output, the BGP-CLASS shows all 50 packets as conformed, meaning they were transmitted, whereas the SNMP-CLASS shows 40 exceeded and 10 violated packets out of 200, indicating 50 packets were dropped because the offered rate of 2000 bps surpassed the 16 kbps policer. On the ENCOR 350-401 exam, this tests your ability to read CoPP output and identify which traffic classes are being policed versus dropped, a common trap being to overlook the violated counter or misinterpret the class-default as a catch-all for all unmatched traffic. Remember the memory tip: “Conformed is good, exceeded and violated are dropped”—focus on the non-zero numbers in the exceeded and violated rows to spot trouble.
⚠ Common exam trap
The trap here is that candidates may misinterpret the 'exceeded' and 'violated' counters as indicating that all traffic in a class is being dropped, when in fact only packets that exceed the policer thresholds are dropped, while conforming traffic is still transmitted.
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
✓
SNMP traffic to the control plane is experiencing drops due to exceeding its policer rate, while BGP traffic is within its rate.
The output shows that for the SNMP-CLASS, 40 packets exceeded and 10 packets violated the policer, resulting in drops, while the BGP-CLASS had 0 exceeded and 0 violated packets, meaning all BGP traffic conformed to its CIR of 64000 bps. This confirms that SNMP traffic is being dropped due to exceeding its policer rate, while BGP traffic is within its 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.
- ✓
SNMP traffic to the control plane is experiencing drops due to exceeding its policer rate, while BGP traffic is within its rate.
Why this is correct
The SNMP class shows 150 conformed and 50 dropped (exceeded+violated), while BGP shows all 50 conformed.
- ✗
BGP traffic is being dropped because it exceeds the CIR.
Why it's wrong here
BGP shows all 50 packets conformed, so no drops.
- ✗
All traffic to the control plane is being dropped.
Why it's wrong here
Only SNMP traffic is being partially dropped; BGP and class-default have no drops.
- ✗
The control-plane policy is applied in the output direction.
Why it's wrong here
The service-policy is input, so it is inbound.
Visual reference
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Same concept, more angles
2 more ways this is tested on 350-401
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A network engineer runs the following command on Router R1: R1# show policy-map control-plane Control Plane Service-policy input: CoPP-POLICY Class-map: ICMP-CLASS (match-all) 10 packets, 1000 bytes 5 minute offered rate 0 bps Match: access-group name ICMP-ACL police: cir 8000 bps, bc 1500 bytes, be 1500 bytes conformed 10 packets, 1000 bytes; actions: transmit exceeded 0 packets, 0 bytes; actions: drop violated 0 packets, 0 bytes; actions: drop Class-map: SSH-CLASS (match-all) 5 packets, 500 bytes 5 minute offered rate 0 bps Match: access-group name SSH-ACL police: cir 16000 bps, bc 3000 bytes, be 3000 bytes conformed 5 packets, 500 bytes; actions: transmit exceeded 0 packets, 0 bytes; actions: drop violated 0 packets, 0 bytes; actions: drop Class-map: class-default (match-any) 20 packets, 2000 bytes 5 minute offered rate 0 bps Match: any police: cir 64000 bps, bc 8000 bytes, be 8000 bytes conformed 20 packets, 2000 bytes; actions: transmit exceeded 0 packets, 0 bytes; actions: drop violated 0 packets, 0 bytes; actions: drop Based on this output, what can be concluded?
hard- ✓ A.ICMP traffic to the control plane is rate-limited to 8 kbps, and all packets so far have been within the conform rate.
- B.SSH traffic to the control plane is being dropped because it exceeds the CIR.
- C.The control-plane policy is applied in the output direction.
- D.All traffic to the control plane is rate-limited to 64 kbps.
Why A: The output shows that for the ICMP-CLASS, the police command sets a CIR of 8000 bps (8 kbps). The counters show 10 packets conformed and 0 packets exceeded or violated, meaning all ICMP traffic to the control plane has been within the conform rate and transmitted. This directly confirms that ICMP traffic is rate-limited to 8 kbps and has not yet exceeded that limit.
Variation 2. A network engineer runs the following command on Router R1: R1# show policy-map control-plane Control Plane Service-policy input: CoPP-POLICY Class-map: MGMT-CLASS (match-all) 100 packets, 5000 bytes 5 minute offered rate 1000 bps Match: access-group name MGMT-ACL police: cir 32000 bps, bc 4000 bytes, be 4000 bytes conformed 80 packets, 4000 bytes; actions: transmit exceeded 15 packets, 750 bytes; actions: drop violated 5 packets, 250 bytes; actions: drop Class-map: class-default (match-any) 200 packets, 10000 bytes 5 minute offered rate 2000 bps Match: any police: cir 64000 bps, bc 8000 bytes, be 8000 bytes conformed 200 packets, 10000 bytes; actions: transmit exceeded 0 packets, 0 bytes; actions: drop violated 0 packets, 0 bytes; actions: drop Based on this output, what can be concluded?
hard- ✓ A.Management traffic to the control plane is being policed, and some packets are being dropped because they exceed the configured rate.
- B.All management traffic is being transmitted without drops.
- C.The policer is configured in the output direction.
- D.The class-default is dropping packets.
Why A: The output shows that the CoPP-POLICY policy map is applied to the control plane in the input direction. For the MGMT-CLASS class, the policer has a CIR of 32000 bps, and the counters show 15 packets exceeded and 5 packets violated, both with a drop action. This confirms that some management traffic is being dropped because it exceeds the configured rate, making option A correct.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 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 350-401 exam.