Traffic Policing
Traffic policing controls the rate of traffic entering a network within a specified range by metering traffic and taking punitive action on excess traffic. This feature protects network resources and interests of the enterprise users.
Implementation of Traffic Policing
As shown in Figure 4-4, traffic policing involves the following components:
Meter: uses the token bucket mechanism to measure network traffic and sends the result to the marker.
Marker: colors packets green, yellow, or red based on the measurement result received from the meter.
Action: performs actions based on packet colors. The following actions are defined:
Pass: forwards the packets that conform to the limit.
Re-mark + pass: changes the local priorities of those packets that exceed the limit and forwards the packets.
Discard: drops the packets that exceed the limit.
If the rate of a packet stream exceeds the limit, the system lowers the priority of extra packets in the stream before forwarding them or discards the packets. By default, the system forwards green and yellow packets, and discards red packets.
