350-401 Security Practice Question
A network engineer is configuring Control Plane Policing (CoPP) on a Cisco IOS XE router to protect against DoS attacks. The router has a management plane that includes SSH and SNMP, and a control plane that includes routing protocols like OSPF and BGP. The engineer wants to rate-limit traffic destined to the route processor while ensuring that management traffic is not dropped during high CPU load. Which CoPP configuration approach is most appropriate?
⚠ Common exam trap
The trap here is assuming that a single CoPP policy with a uniform rate limit is sufficient, overlooking the need to prioritize management traffic to prevent lockout during an attack.
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
✓
Configure separate classes for management traffic (SSH, SNMP) and control plane traffic (OSPF, BGP), and assign higher rate limits to management traffic.
CoPP allows granular control over traffic destined to the route processor. By separating management and control plane traffic into different classes, the engineer can assign higher rate limits to management traffic to ensure administrative access is maintained, while still protecting the route processor from excessive control plane traffic. This approach balances security and availability, preventing both DoS attacks and administrator lockout.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure separate classes for management traffic (SSH, SNMP) and control plane traffic (OSPF, BGP), and assign higher rate limits to management traffic.
Why this is correct
This is the best practice. By creating separate classes, the engineer can apply different rate limits. Management traffic should have a higher rate limit to ensure administrators can always access the device, while control plane protocols can have lower limits to protect the route processor. This granularity ensures that critical management access is not starved during an attack, and routing protocols are still protected but not at the expense of management access.
- ✗
Use a single class that matches all IP traffic and set a high rate limit to avoid dropping any packets.
Why it's wrong here
Setting a high rate limit defeats the purpose of CoPP, which is to protect the route processor from being overwhelmed. A high rate limit could allow a DoS attack to consume CPU resources. CoPP should rate-limit traffic to the control plane to a reasonable level, not allow all traffic. This approach does not provide protection and may lead to device instability under attack.
- ✗
Apply a single CoPP policy that classifies all traffic to the route processor and sets a low rate limit for all classes.
Why it's wrong here
Applying a single low rate limit to all traffic could cause management traffic to be dropped during high load, which is undesirable. Management traffic like SSH and SNMP should be prioritized to ensure administrators can access the device even under attack. A one-size-fits-all policy does not differentiate between critical management traffic and potentially malicious traffic, leading to potential lockout or monitoring gaps.
- ✗
Configure CoPP only for routing protocols and rely on QoS for management traffic.
Why it's wrong here
CoPP is specifically designed to protect the control plane, which includes management traffic. Relying on QoS for management traffic does not protect the route processor from being overwhelmed by malicious traffic. QoS is for egress or ingress scheduling, not for policing traffic destined to the CPU. Management traffic should be included in CoPP policies to ensure its delivery during attacks.
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
Learn chapter
SDN Controllers and Cisco ACI
Key term
Control Plane Protection
Control Plane Protection (CoPP) is a security feature on Cisco routers and switches that filters traffic destined to the device's control plane to prevent attacks and ensure stability.
Key term
Control Plane Policing
Control Plane Policing is a Cisco security feature that protects a router or switch by rate-limiting the traffic that the device's processor must handle, preventing it from being overwhelmed.
About these practice questions
This 350-401 question is part of Courseiva's 1,923-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 and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.