Explanation/Reference:
Explanation:
Starting with Cisco IOS Software release 12.4(4)T, Control Plane Protection (CPPr) can be used to restrict
and/or police control plane traffic destined to the route processor of the Cisco IOS device. Although it is
similar to Control Plane Policing (CoPP), CPPr has the ability to restrict/police traffic using finer granularity
than that used by CoPP. CPPr divides the aggregate control plane into three separate control plane
categories, known as subinterfaces: (1) host, (2) transit, and (3) CEF-exception. In addition, CPPr includes
the following additional control plane protection features:
The port-filtering feature provides for policing/dropping of packets going to closed or nonlistening TCP/

UDP ports
Queue thresholding limits the number of packets for a specified protocol that will be allowed in the

control plane IP input queue
Reference: http://www.cisco.com/c/en/us/about/security-center/understanding-cppr.html