FR traffic policing
FR traffic policing monitors the traffic entering the network from each PVC and restricts the traffic within a permitted range. If the traffic on a PVC exceeds the user-defined threshold, the device takes some measures, like packet drop, to protect the network resources.
Figure 45: FR traffic policing implementation
As shown in Figure 45, Router A at the user side transmits packets at the rate of 192 kbps to Router B at the switching side. However, Router B only wants to provide the bandwidth of 64 kbps for Router A. Therefore, you must configure FR traffic policing at the DCE side of Router B.
FR traffic policing can only be applied to the DCE interface of a device. FR traffic policing can monitor the traffic transmitted from the DTE side. When the traffic is smaller than CBS, the packets can be transmitted, and the device does not process the packets. When the traffic is larger than CBS and smaller than EBS + CBS, the packets can be transmitted. However, as for those packets of the traffic exceeding CBS, the device sets the DE flag bits in the FR packet headers to 1. When the traffic is larger than CBS + EBS, the device transmits the traffic of CBS + EBS and drops the traffic exceeding CBS + EBS. As for the traffic exceeding CBS, the device sets the DE flag bits in the FR packet headers to 1.