Question 2 of 500
SecurityhardMultiple ChoiceObjective-mapped

Quick Answer

The correct configuration applies a Control Plane Policing (CoPP) policy that matches ICMP traffic and rate-limits it to 1000 packets per second with a 200-byte burst, as shown in Option D. This works because the class-map type control-plane match-all COPP-ICMP uses the match protocol icmp statement to isolate ICMP TTL exceeded messages that are process-switched, and the police command in the policy-map caps their rate, preventing CPU spikes that cause BGP flaps while leaving all other control plane traffic unrestricted. On the Cisco DCCOR 350-601 exam, this question tests your ability to differentiate CoPP from control plane protection features like CPPr or hardware rate-limiters; a common trap is applying the policy under an interface instead of the global control-plane configuration. Remember that NX-OS requires the service-policy type control-plane command under the control-plane submode, not the interface. Memory tip: “ICMP spikes? CoPP it with police pps and burst—keep the rest unrestricted.”

350-601 Security Practice Question

This 350-601 practice question tests your understanding of security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 data center network uses Cisco Nexus 9000 switches running NX-OS. The operations team notices that the CPU utilization on the supervisor module spikes intermittently, causing BGP session flaps. Analysis shows that the CPU spikes coincide with traceroute probes from external networks, which generate ICMP TTL exceeded messages that are process-switched. The engineer must implement a solution to protect the control plane without affecting normal ICMP functionality. The goal is to rate-limit ICMP traffic to a maximum of 1000 packets per second with a burst of 200 bytes, while allowing other control plane traffic without restriction. Which configuration should be applied?

Question 1hardmultiple choice
Open the full BGP breakdown →

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

class-map type control-plane match-all COPP-ICMP match protocol icmp policy-map type control-plane COPP class COPP-ICMP police 1000 pps 200 byte burst control-plane service-policy type control-plane COPP

Option D is correct because it uses a Control Plane Policing (CoPP) policy with a class-map that matches ICMP protocol traffic in the control plane, then applies a police rate of 1000 pps with a 200-byte burst. This configuration rate-limits ICMP TTL-exceeded messages that are process-switched, protecting the supervisor CPU from spikes while allowing other control plane traffic unrestricted. The 'service-policy type control-plane' command applies the policy to the control plane, which is the proper method for NX-OS CoPP.

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.

  • Use the 'hardware rate-limiter' feature to limit ICMP globally.

    Why it's wrong here

    Hardware rate-limiters are less granular and not recommended for specific protocol control; CoPP is preferred.

  • class-map type control-plane match-any COPP-ICMP match access-group name ICMP-ACL policy-map type control-plane COPP class COPP-ICMP police rate 1000 pps burst 200 control-plane service-policy input COPP

    Why it's wrong here

    Incorrect: match-any is not necessary; police rate is invalid; service-policy should be type control-plane, not input.

  • Apply a QoS policy on the management interface to drop excess ICMP.

    Why it's wrong here

    This would affect only management interface traffic, not control plane traffic from data ports.

  • class-map type control-plane match-all COPP-ICMP match protocol icmp policy-map type control-plane COPP class COPP-ICMP police 1000 pps 200 byte burst control-plane service-policy type control-plane COPP

    Why this is correct

    Correct syntax: using type control-plane class-map and policy-map, with police in pps and burst in bytes.

    Related concept

    Read the scenario before looking for a memorised answer.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Cisco often tests the distinction between applying a policy-map with 'service-policy input' (which is for interface QoS) versus 'service-policy type control-plane' (which is for CoPP), and the correct police syntax including the 'byte' keyword for burst size.

Detailed technical explanation

How to think about this question

Control Plane Policing (CoPP) on Cisco NX-OS uses a dedicated 'type control-plane' class-map and policy-map to filter traffic destined to the supervisor CPU. The 'match protocol icmp' class-map matches all ICMP packets, including TTL-exceeded messages (Type 11), which are process-switched and can cause CPU spikes. The police command with 'pps' and 'byte burst' enforces a rate limit; the burst size in bytes allows for short bursts of ICMP packets without dropping, smoothing the rate enforcement. In real-world scenarios, misconfigured traceroute probes or ICMP flood attacks can overwhelm the control plane, and CoPP is the standard defense without blocking legitimate ICMP functionality.

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.

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.

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FAQ

Questions learners often ask

What does this 350-601 question test?

Security — This question tests Security — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: class-map type control-plane match-all COPP-ICMP match protocol icmp policy-map type control-plane COPP class COPP-ICMP police 1000 pps 200 byte burst control-plane service-policy type control-plane COPP — Option D is correct because it uses a Control Plane Policing (CoPP) policy with a class-map that matches ICMP protocol traffic in the control plane, then applies a police rate of 1000 pps with a 200-byte burst. This configuration rate-limits ICMP TTL-exceeded messages that are process-switched, protecting the supervisor CPU from spikes while allowing other control plane traffic unrestricted. The 'service-policy type control-plane' command applies the policy to the control plane, which is the proper method for NX-OS CoPP.

What should I do if I get this 350-601 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.

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Last reviewed: Jun 24, 2026

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