Peak information rate (PIR)—Rate at which tokens are put into bucket E, which specifies the average
packet transmission or forwarding rate allowed by bucket E.
Excess burst size (EBS)—Size of bucket E, which specifies the transient burst of traffic that bucket E
CBS is implemented with bucket C, and EBS with bucket E. In each evaluation, packets are measured
against the following bucket scenarios:
If bucket C has enough tokens, packets are colored green.
If bucket C does not have enough tokens but bucket E has enough tokens, packets are colored
If neither bucket C nor bucket E has sufficient tokens, packets are colored red.
Traffic policing supports policing the inbound traffic and the outbound traffic.
A typical application of traffic policing is to supervise the specification of certain traffic entering a
network and limit it within a reasonable range, or to "discipline" the extra traffic to prevent aggressive
use of network resources by a certain application. For example, you can limit bandwidth for HTTP
packets to less than 50% of the total. If the traffic of a certain session exceeds the limit, traffic policing can
drop the packets or reset the IP precedence of the packets.
outbound traffic on an interface.
Figure 9 Traffic policing
Traffic policing is widely used in policing traffic entering the networks of internet service providers (ISPs).
It can classify the policed traffic and take pre-defined policing actions on each packet depending on the
Forwarding the packet if the evaluation result is "conforming"
Dropping the packet if the evaluation result is "excess"
Forwarding the packet with its precedence, which can be 802.1p priority, DSCP, and local
precedence, re-marked if the evaluation result is "conforming"
shows an example of policing