Control Plane Protection
Control Plane Protection or CPPr is an extension of Control Plane Policing (CoPP). Cisco puts it this way:
The Control Plane Protection feature is an extension of the policing functionality provided by the existing Control-Plane Policing feature. The Control-Plane Policing feature allows Quality of Service (QoS) policing of aggregate control-plane traffic destined to the route processor. The Control Plane Protection feature extends this policing functionality by allowing finer policing granularity.
The functionality added with Control Plane Protection includes a traffic classifier, which intercepts traffic and classifies it into three control-plane categories. New port-filtering and queue-thresholding features have also been added. The port-filtering feature provides for policing of packets going to closed or nonlistened TCP/UDP ports, while queue-thresholding limits the number of packets for a specified protocol that will be allowed in the control-plane IP input queue.