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400-007 · Question #390

A thorough examination of the curant network infrastructure has revealed that several devices have an unusual high CPU load. A traffic analysis indicates that control plane protocols and management…

The correct answer is A. control plane policing. Control Plane Policing (CoPP) is the Cisco IOS feature specifically designed to protect the router CPU by rate-limiting or dropping traffic destined to the control plane.

Designing Management and Operations

Question

A thorough examination of the curant network infrastructure has revealed that several devices have an unusual high CPU load. A traffic analysis indicates that control plane protocols and management traffic are affected as the devices are busy processing inbound traffic. The networking team is working on updating their design for the entre network to handle situations like this. Which feature or technology can be added to help mitigate the problem?

Options

  • Acontrol plane policing
  • Bdeep uterface buffers
  • CTCAM carving
  • Dmodular QoS

How the community answered

(45 responses)
  • A
    78% (35)
  • B
    13% (6)
  • C
    4% (2)
  • D
    4% (2)

Why each option

Control Plane Policing (CoPP) is the Cisco IOS feature specifically designed to protect the router CPU by rate-limiting or dropping traffic destined to the control plane.

Acontrol plane policingCorrect

CoPP defines QoS-style policies that rate-limit or drop specific types of control plane and management traffic before they reach the route processor, directly preventing CPU exhaustion from traffic floods targeting control plane protocols such as OSPF, BGP, SNMP, and SSH.

Bdeep uterface buffers

Deep interface buffers absorb short bursts of data plane traffic at ingress and egress queues but do not police or limit traffic directed at the router CPU for control plane processing.

CTCAM carving

TCAM carving reallocates on-chip memory between features such as routing tables, ACLs, and QoS entries but does not rate-limit or filter traffic directed to the control plane processor.

Dmodular QoS

Modular QoS (MQC) can classify and schedule data plane traffic on interfaces but is not designed to protect the control plane CPU from being overwhelmed by inbound control and management traffic.

Concept tested: Control Plane Policing to protect router CPU

Source: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/qos_copp/configuration/xe-16/qos-copp-xe-16-book/qos-copp-feature-guide.html

Topics

#control plane policing#CoPP#CPU utilization#traffic management

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