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This chapter is from the book

Control Plane Policing (CoPP) Feature

The traffic managed by a device can be divided into three functional components or planes:

  • Data plane
  • Management plane
  • Control plane

The vast majority of traffic flows through the device via the data plane; however, the route processor handles certain traffic, such as routing protocol updates, remote-access services, and network management traffic such as SNMP. This type of traffic is referred to as the control and management plane. The route processor is critical to network operation. Therefore any service disruption or security compromise to the route processor, and hence the control and management planes, can result in network outages that impact regular operations. For example, a DoS attack targeting the route processor typically involves high bursty traffic resulting in excessive CPU utilization on the route processor. Such attacks can be devastating to network stability and availability. The bulk of traffic managed by the route processor is handled by way of the control and management planes.

The CoPP feature is used to protect the aforementioned control and management planes; to ensure stability, reachability, and availability and to block unnecessary or DoS traffic. CoPP uses a dedicated control plane configuration through the modular QoS CLI (MQC) to provide filtering and rate limiting capabilities for the control plane packets.

As mentioned earlier, the CoPP feature is available on all major Cisco router series including ISR. Table 4-2 provides a complete list of compatible hardware and software support.

Table 4-2. CoPP Support on Cisco Routers

Router Models

Cisco IOS Software Release

Cisco 12000 Series

Release 12.0(29)S and later

Cisco 7600 Series

Release 12.2(18)SXD1 and later

Cisco 6500 Series

Release 12.2(18)SXD1 and later

Cisco 7200 Series

Cisco 7500 Series

Release 12.2(18)S and later

Cisco 1751 Router

Cisco 2600/2600-XM Series

Cisco 3700 Series

Cisco 7200 Series

Release 12.3(4)T and later

Cisco 1800 Series

Cisco 2800 Series

Release 12.3(8)T and later

Cisco 3800 Series

Release 12.3(11)T and later

Perform the following steps to configure and apply the CoPP feature:

  • Step 1 Define a packet classification criterion. There are a number of ways to categorize the type of traffic—for example, by using an access list or protocol or IP precedence values.
    • Hostname(config)# class-map {traffic_class_name}
      Hostname(config-cmap)# match {access-list | protocol | ip prec | ip dscp | vlan}
  • Step 2 Define a service policy. Note that flow policing is the only valid option available (as of this writing) in the policy map for CoPP.
    • Hostname(config-pmap)# policy-map {service_policy_name}
      Hostname(config-pmap)# class {traffic_class_name}
      Hostname(config-pmap-c)# police <rate> conform-action <action> exceed-action <action>
  • Step 3 Enter control plane configuration mode using the control-plane global command. In this CP submode, the service policies are attached to the control plane.
    • Hostname(config)# control-plane
  • Step 4 Apply QoS policy configured to the control plane.
    • Hostname(config-cp)# service-policy {input | output} {service_policy_name}
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