Control Plane Policing (CoPP)

Control Plane Policing or CoPP is a feature that allows the filtering and rate limiting of control plane traffic, that is, traffic that is generated by the router, as well as traffic that is destined to the router.

ACLs will only filter transient traffic. More about this can be found at ACLs Filtering Locally Generated Traffic.

Links: https://networklessons.com/cisco/ccie-routing-switching-written/copp-control-plane-policing