Cisco IE-3000-8TC Software Configuration Guide - Page 704

Configuring Standard QoS Chapter 36 Configuring QoS This example shows how to create a class map called class2, which matches incoming traffic with DSCP values of 10, 11, and 12. Switch(config)# class-map class2 Switch(config-cmap)# match ip dscp 10 11 12 Switch(config-cmap)# end Switch# This example shows how to create a class map called class3, which matches incoming traffic with IP-precedence values of 5, 6, and 7: Switch(config)# class-map class3 Switch(config-cmap)# match ip precedence 5 6 7 Switch(config-cmap)# end Switch# Classifying, Policing, and Marking Traffic on Physical Ports by Using Policy Maps You can configure a policy map on a physical port that specifies which traffic class to act on. Actions can include trusting the CoS, DSCP, or IP precedence values in the traffic class; setting a specific DSCP or IP precedence value in the traffic class; and specifying the traffic bandwidth limitations for each matched traffic class (policer) and the action to take when the traffic is out of profile (marking). A policy map also has these characteristics: • A policy map can contain multiple class statements, each with different match criteria and policers. • A separate policy-map class can exist for each type of traffic received through a port. • A policy-map trust state and a port trust state are mutually exclusive, and whichever is configured last takes affect. Follow these guidelines when configuring policy maps on physical ports: • You can attach only one policy map per ingress port. • If you configure the IP-precedence-to-DSCP map by using the mls qos map ip-prec-dscp dscp1...dscp8 global configuration command, the settings only affect packets on ingress interfaces that are configured to trust the IP precedence value. In a policy map, if you set the packet IP precedence value to a new value by using the set ip precedence new-precedence policy-map class configuration command, the egress DSCP value is not affected by the IP-precedence-to-DSCP map. If you want the egress DSCP value to be different than the ingress value, use the set dscp new-dscp policy-map class configuration command. • If you enter or have used the set ip dscp command, the switch changes this command to set dscp in its configuration. • You can use the set ip precedence or the set precedence policy-map class configuration command to change the packet IP precedence value. This setting appears as set ip precedence in the switch configuration. • A policy-map and a port trust state can both run on a physical interface. The policy-map is applied before the port trust state. 36-44 Cisco IE 3000 Switch Software Configuration Guide OL-13018-03