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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
78-17058-01
Chapter 30 Configuring QoS
Understanding QoS
After you create a table map, you configure a policy-map policer to use the table map.
• You can configure only one exceed-action police markdown table map of each type (CoS, DSCP, or
IP precedence) on the switch. You can reference that table map in multiple policers.
• When you use a table map in an input policy map, the protocol type for the from–action in the table
map must be the same as the protocol type of the associated classification. For example, if a class
map represents IP classification, the from–type action in the table map must be either dscp or
precedence. If the class map represents a non-IP classification, the from–type action in the table
map must be cos.
To configure multiple actions in a class, you can enter multiple conform or exceed action entries in
policy-map class police configuration mode, as in this example:
Switch(config)# policy-map map1
Switch(config-pmap)# class class1
Switch(config-pmap-c)# police 100000 500000
Switch(config-pmap-c-police)# conform-action set-cos-transmit 4
Switch(config-pmap-c-police)# conform-action set-dscp-transmit 48
Switch(config-pmap-c-police)# exceed-action drop
Switch(config-pmap-c-police)# exit
Switch(config-pmap-c)# exit
Switch(config-pmap)# exit
Aggregate Policing
Aggregate policing applies only to input policy maps. An aggregate policer differs from an individual
policer because it is shared by multiple traffic classes within a policy map.
Note Aggregate policing is not supported for the class class-default.
You can use the policer aggregate global configuration command to set a policer for all traffic received
or sent on a physical interface. When you configure an aggregate policer, you can configure specific
burst sizes and conform and exceed actions. If you do not specify burst size (bc), the system calculates
an appropriate burst size value. The calculated value is appropriate for most applications.
Note You cannot configure marking simultaneously in both conform-action and exceed-action for the same
policer instance.
Conform actions are to send the packet without modifications, to set a QoS group value for classification
at the egress, or to set a new CoS, DSCP, or IP precedence value. Exceed actions are to drop the packet
or to set a new CoS, DSCP, or IP precedence to a value defined in a table map and then send the packet.
Table maps list specific traffic attributes and map (or convert) them to other attributes.
After you create a table map, you configure a policy-map policer to use the table map.
• You can configure only one exceed-action police markdown table map of each type (CoS, DSCP, or
IP precedence) on the switch. You can reference that table map in multiple policers.
• When you use a table map in an input policy map, the protocol type for the from–action in the table
map must be the same as the protocol type of the associated classification. For example, if a class
map represents IP classification, the from–type action in the table map must be either dscp or
precedence. If the class map represents a non-IP classification, the from–type action in the table
map must be cos.