Benefits Of Class-Based Policing; Restrictions For Class-Based Policing - Cisco ASR 900 Series Configuration Manual

Benefits of Class-Based Policing

Class-based policing allows you to control the maximum rate of traffic transmitted or received on an interface.
The Class-Based Policing feature is applied when you attach a traffic policy that contains the class-based
policing configuration to an interface.
The Class-Based Policing feature works with a token bucket mechanism. There are currently two types of
token bucket algorithms: a single token bucket algorithm and a two-token bucket algorithm. A single token
bucket system is used when the violate-action option is not specified, and a two-token bucket system is used
when the violate-action option is specified.
Benefits of Class-Based Policing
Bandwidth Management Through Rate Limiting
Class-based policing allows you to control the maximum rate of traffic transmitted or received on an interface.
Class-based policing is often configured on interfaces at the edge of a network to limit traffic into or out of
the network. In most class-based policing configurations, traffic that falls within the rate parameters is
transmitted, whereas traffic that exceeds the parameters is dropped or transmitted with a different priority.
Packet Marking
Packet marking allows you to partition your network into multiple priority levels or classes of service (CoS).
A packet is marked and these markings can be used to identify and classify traffic for downstream devices.
• Use class-based policing to set the IP precedence or DSCP values for packets entering the network.
• Use class-based policing to assign packets to a QoS group. The router uses the QoS group to determine
Traffic can be marked without using the Class-Based Policing feature.

Restrictions for Class-Based Policing

Restrictions for the Cisco ASR 900 Router
• Hierarchical policing (policing at both parent level and child level) is not supported.
QoS: Policing and Shaping Configuration Guide, Cisco IOS XE Release 3S (Cisco ASR 900 Series)
2
The output transmission rate of a class of traffic based on user-defined criteria is not
Note
supported on the Cisco ASR 900 RSP3 Module.
Networking devices within your network can then use the adjusted IP precedence values to determine
how the traffic should be treated.
how to prioritize packets.
Class-Based Policing