Traffic policing controls the rate of incoming packets to ensure that network resources are properly allocated. If the traffic rate of a connection exceeds the specifications on an interface, traffic policing allows the interface to drop excess packets or re-mark the packet priority to maximize network resource usage and protect carriers' profits. An example of this process is restricting the rate of HTTP packets to 50% of the network bandwidth.
Traffic policing implements the QoS requirements defined in the service level agreement (SLA). The SLA contains parameters, such as the committed information rate (CIR), peak information rate (PIR), committed burst size (CBS), and peak burst size (PBS) to monitor and control incoming traffic. The device performs Pass, Drop, or Markdown actions for the traffic exceeding the specified limit. Markdown means that packets are marked with a lower service class or a higher drop precedence so that these packets are preferentially dropped when traffic congestion occurs. This measure ensures that the packets conforming to the SLA can have the services specified in the SLA.