Traffic Policing
By using the QoS policing function, bandwidth use can be controlled on
physical interfaces. Policing specifies an amount of bandwidth allowed for a
particular type of traffic, and generally drops traffic over that amount. It can
also be configured to allow the excess traffic, but it marks it with a different
(usually lower) DSCP value.
Some uses for policing include:
■ Limiting the bandwidth of a high-speed interface to a lower rate
■ Limiting the rate of an application or a traffic class
■ Remarking the DSCP of traffic exceeding a specified rate
Class-based policing is configured in a policy map. Its possible conditions
are: Conform, Exceed, and Violate. Its possible actions are: Drop, Set
(DSCP, for example), and Transmit.