350-401 Question 255
Select 3A network administrator observes that excessive ARP requests and ICMP traffic directed at the control plane of a router are impacting its performance. To mitigate this issue, the administrator decides to implement Control Plane Policing (CoPP). Which of the following actions are appropriate when configuring CoPP to protect the router's control plane from such traffic?
- A
Create a class map to match ARP and ICMP traffic.
- B
Apply an access control list (ACL) directly to the control plane interface.
- C
Define a policy map to specify policing actions for the class map.
- D
Apply the policy map to the control plane using the 'control-plane' configuration mode.
- E
Use CoPP to block all traffic to the control plane.
Show answer and explanation
Correct answers: A, C, D
Explanation
Control Plane Policing (CoPP) is a feature that allows administrators to manage and protect the control plane of a network device from excessive or malicious traffic. To configure CoPP, you first create a class map to identify specific traffic, define a policy map to specify actions for that traffic, and then apply the policy map to the control plane using the 'control-plane' configuration mode. This approach ensures that only unwanted or excessive traffic is mitigated, while legitimate traffic can still reach the control plane.
- A. Correct.
Correct. Creating a class map to match ARP and ICMP traffic is a necessary first step in identifying the traffic types that need to be policed.
- B. Incorrect.
Incorrect. ACLs cannot be directly applied to the control plane interface. Instead, they should be referenced within a class map as part of the CoPP configuration.
- C. Correct.
Correct. A policy map is used to define actions (e.g., policing, dropping, or permitting traffic) for the matched traffic defined in the class map.
- D. Correct.
Correct. The policy map is applied to the control plane using the 'control-plane' configuration mode to enforce CoPP rules.
- E. Incorrect.
Incorrect. CoPP should not block all traffic to the control plane, as legitimate control traffic (e.g., routing protocol updates) must still be allowed for proper network operation.