CCNP Security Practice Question
A network administrator is deploying Control Plane Policing (CoPP) on a Cisco IOS XE router that runs BGP, SSH, and NTP. The requirement is to protect the route processor from excessive BGP keepalive traffic while still allowing all legitimate BGP peering. Which CoPP module should the administrator use to classify and police this traffic before the policy is applied to the control plane?
⚠ Common exam trap
The trap here is assuming a route map or interface ACL can police traffic destined to the route processor, when CoPP specifically requires a policy map attached to the control plane.
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
✓
A class map that matches BGP traffic using an ACL or NBAR, referenced by a policy map, which is then applied with the service-policy command under control-plane configuration mode.
Control Plane Policing requires a modular QoS configuration: class maps to identify traffic, a policy map to define policer actions, and the service-policy command applied under control-plane configuration mode. This structure allows BGP keepalives to be matched and policed while other traffic is handled separately, directly protecting the route processor as the scenario requires.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
A class map that matches BGP traffic using an ACL or NBAR, referenced by a policy map, which is then applied with the service-policy command under control-plane configuration mode.
Why this is correct
CoPP on IOS XE uses a modular QoS CLI structure: class maps identify control-plane traffic, a policy map defines policing actions, and the policy is attached to the control plane with service-policy under control-plane mode. Matching BGP via ACL or NBAR lets the administrator police keepalives while permitting other BGP flows, which satisfies the stated requirement.
- ✗
A route map applied inbound on the BGP neighbor session that sets a lower precedence for keepalive packets.
Why it's wrong here
Route maps manipulate BGP path attributes and route selection; they do not police or rate-limit control-plane packets destined to the route processor. Applying a route map to a neighbor cannot protect the CPU from a flood of BGP keepalives, so it does not meet the requirement of protecting the route processor with CoPP.
- ✗
A class map referenced by a policy map that is applied outbound on the WAN interface toward the BGP peer.
Why it's wrong here
CoPP policies are applied to the control plane, not outbound on a data interface. Applying a policy map outbound on the WAN interface affects traffic leaving the router, not traffic destined to the route processor, so it cannot protect the CPU from excessive BGP keepalive packets as required.
- ✗
An access list applied directly to the physical interface facing the BGP peer using the ip access-group command.
Why it's wrong here
An interface ACL filters transit and ingress traffic but does not specifically target the control plane, and it cannot apply policing actions such as rate limiting to CPU-bound traffic. It also risks blocking legitimate BGP updates if not carefully scoped, so it is not the correct CoPP mechanism for protecting the route processor.
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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.