Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2SecurityMedium

A network security team is implementing infrastructure security measures on a Cisco router. They want to protect the router's CPU from excessive traffic during a denial-of-service (DoS) attack, specifically targeting management protocols like Telnet, SSH, and SNMP. Which security mechanism should be configured to rate-limit and filter these types of packets destined for the router's control plane?

  1. AManagement Plane Policing (MPP)
  2. BUnicast Reverse Path Forwarding (uRPF)
  3. CData Plane Policing (DPP)
  4. DControl Plane Policing (CoPP)
Show answer & explanation

Correct answer: D. Control Plane Policing (CoPP)

Control Plane Policing (CoPP) is designed to protect the router's CPU (control plane) from excessive traffic, including attacks and legitimate but high-volume traffic, by classifying and rate-limiting packets destined to the router itself. This directly targets the protection of management protocols like Telnet, SSH, and SNMP.

Why the other options are wrong

  • A. Management Plane Policing (MPP) is a simpler, less granular feature focused on protecting management interfaces (e.g., VTY, console, aux) from management traffic.
  • B. Unicast Reverse Path Forwarding (uRPF) helps mitigate IP spoofing by verifying the source IP address of packets, not protecting the control plane directly.
  • C. Data Plane Policing (DPP) applies rate limiting to user data traffic transiting the router.

Control Plane Policing (CoPP)

A Cisco IOS feature that protects the router's CPU (control plane) from excessive traffic, including malicious attacks and legitimate overhead, by applying QoS policies to traffic destined for the router itself.

  • Uses a modular QoS command-line interface (MQC) to classify and police traffic.
  • Protects management protocols (SSH, Telnet, SNMP), routing protocols (OSPF, EIGRP), and infrastructure protocols (ARP, ICMP).
  • Prevents DoS attacks from overwhelming the CPU and impacting router stability.
  • Operates on traffic destined to the router, not traffic transiting it.

Memory trick: Planes Operate: Control for CPU, Data for Forwarding, Management for Access

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