What are three facts control plane policing？ （）

• A、a set of rules that can be established and associated with the ingress and egress ports of the control plane
• B、improves performance of the control plane by marking control plane packets with DSCPEF
• C、protects the control plane on a router from DoS attacks
• D、treats the control plane as a separate entity with its own ingress （input） and egress （output） ports
• E、provides the control plane with a separate token bucket
• F、enhances security of the control plane by tunneling packets to and from the control plane