Control Plane Protection

Control plane protection (CPPr) is another feature, similar to control plane policing, that can help to mitigate the effects on the CPU of traffic that requires processing by the CPU.

CPPr can restrict traffic with finer granularity by dividing the aggregate control plane into three separate control plane categories known as subinterfaces. The three subinterfaces are as follows:

Host subinterface

Transit subinterface

CEF-Exception subinterface

In addition to providing three more granular buckets in which to place packets destined to the device’s control plane, the CPPr feature also additionally provides the following:

Port-filtering feature: Enables the policing and dropping of packets that are sent to closed or nonlistening TCP or UDP ports

Queue-thresholding feature: Limits the number of packets for a specified protocol that are allowed in the control-plane IP input queue