Cisco Systems 3560 Manual De Usuario
34-48
Catalyst 3560 Switch Software Configuration Guide
OL-8553-06
Chapter 34 Configuring QoS
Configuring Standard QoS
Classifying, Policing, and Marking Traffic on Physical Ports by Using Policy Maps
You can configure a nonhierarchical 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).
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.
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.
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.
•
In Cisco IOS Release 12.2(25)SE or later, if you enter or have used the set ip dscp command, the
switch changes this command to set dscp in its configuration.
switch changes this command to set dscp in its configuration.
•
In Cisco IOS Release 12.2(25)SEC or later, 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.
policy-map class configuration command to change the packet IP precedence value. This setting
appears as set ip precedence in the switch configuration.
•
In Cisco IOS Release 12.2(25)SED or later, you can configure a separate second-level policy map
for each class defined for the port. The second-level policy map specifies the police action to take
for each traffic class. For information on configuring a hierarchical policy map, see
for each class defined for the port. The second-level policy map specifies the police action to take
for each traffic class. For information on configuring a hierarchical policy map, see
•
Beginning with Cisco IOS Release 12.2(40)SE, 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.
a physical interface. The policy-map is applied before the port trust state.